There are no acknowledgments.

1. Drying of toluene
NOTE: If you have access to dry solvent towers, collect the toluene and degas by five freeze-pump-thaw cycles.
<ol>
	<li>Dry 3 &#197; molecular sieves in a 250 mL Schlenk flask at 250-300 &#176;C under vacuum for 48 h and transfer into a glovebox.</li>
	<li>Dry two ampoules in the oven at 150 &#176;C overnight and transfer them into the glovebox.</li>
	<li>Transfer the activated molecular sieves into the two ampoules and remove from the glovebox.</li>
	<li>Dry a two-neck round-bottom flask (RBF) and add 100 mL of toluene, the volume of which equals to, at most, half of the ampoule volume. Add 1.0 g of CaH2 to the toluene and stir. 
	CAUTION: Be careful of H2 release at this point. Always add CaH2 under a steady flow of nitrogen to remove any H2 build up in the flask.</li>
	<li>Transfer the toluene into one of the ampoules containing the molecular sieves with a filter cannula and rest overnight.</li>
	<li>Transfer the toluene into the last ampoule containing sieves with a filter cannula. Freeze-pump-thaw (5 cycles) the toluene and transfer into a glovebox.</li>
</ol>
2. Drying of the CTA-initiator/DPP
<ol>
	<li>Add the chain transfer agent/initiator to a vial, securing with tissue paper.</li>
	<li>Add 10 g of P2O5 into a desiccator. Place the vial above the powder.</li>
	<li>Place the desiccator under dynamic vacuum for 8 h and static vacuum overnight.</li>
	<li>Open the desiccator to agitate the P2O5. Resume the vacuum cycles for 5 days. 
	NOTE: The P2O5 may discolor or become clumpy if excess solvent/water is present. Replace the P2O5 if this is observed.</li>
	<li>Backfill the desiccator with nitrogen and transfer to a glovebox.</li>
</ol>
3. Drying/Purification of &#949;-caprolactone
NOTE: For this section, all glassware and stirrer bars must have been dried in a 150 &#176;C oven overnight prior to use. This will remove all water from the surfaces of the glass.
<ol>
	<li>Add 100 mL of &#949;-caprolactone to a two-neck 250 mL RBF equipped with a stirrer bar and tap on the small neck.</li>
	<li>Add 1.0 g of calcium hydride into the RBF, under a steady flow of nitrogen. Fit with a glass stopper and stir overnight at room temperature under a nitrogen atmosphere.</li>
	<li>Dry the vacuum distillation equipment.</li>
	<li>Attach the two-neck flask to a Schlenk line and purge by evacuating and filling with nitrogen three times. After purging, open the line to a steady flow of nitrogen.</li>
	<li>Assemble the vacuum distillation equipment from the &#949;-caprolactone RBF, maintaining a steady flow of nitrogen to prevent water from entering the system. Attach the thermometer and seal in place.</li>
	<li>Attach the adaptor to the Schlenk line. Remove the nitrogen flow and place the system under vacuum under this new connection.</li>
	<li>Heat the &#949;-caprolactone at 60-80 &#176;C, collecting the first 5.0 mL in the small RBFs and the rest in the two-neck RBF. Place the flasks in liquid nitrogen to condense the caprolactone effectively. Wrap the distillation equipment in cotton wool and foil to speed up the process.</li>
	<li>Attach the Schlenk line to the collection flask and purge the line three times. Turn the line to nitrogen and open the tap. Add 1.0 g of calcium hydride to the flask, and a stopper, then leave under a nitrogen atmosphere stirring overnight.</li>
	<li>Meanwhile, dispose of the excess calcium hydride by the dropwise addition of isopropanol, followed by 5.0 mL of methanol and then an excess of water once bubbling ceases. Rinse the glassware with acetone and place in the oven overnight.</li>
	<li>Repeat the vacuum distillation again, without adding CaH2 to the monomer once finished. Instead, transfer the caprolactone via cannula into an ampoule and transfer to the glovebox.</li>
</ol>
4. Ring opening polymerization of &#949;-caprolactone
<ol>
	<li>Prepare stock solutions of initiator, catalyst and monomer. Weigh 0.10 g of diphenyl phosphate, 0.011 g of CTA-OH and 0.25 g of caprolactone into three separate vials. Add 0.5 mL of toluene to each of the initiator and catalyst vials and gently agitate until the reagents are dissolved.</li>
	<li>Mix the initiator and diphenyl phosphate stock solutions into one vial and add a stir bar.</li>
	<li>Under moderate stirring, add the monomer into the initiator/catalyst vial. Fit the vial with a lid and stir for 8 h at room temperature.</li>
	<li>After 8 h, remove the vial from the glovebox and immediately precipitate into an excess of cold diethyl ether dropwise.</li>
	<li>Filter the white solid, dry and dissolve in 1 mL of tetrahydrofuran (THF). Precipitate twice more and dry thoroughly.</li>
</ol>
5. RAFT polymerization of methyl methacrylate and N,N-dimethylacrylamide
<ol>
	<li>To remove the stabilizers from the dioxane and MMA, prepare several basic alumina plugs in Pasteur pipettes and filter the liquids into separate vials.</li>
	<li>Weigh 0.5 g of PCL synthesized previously, 0.424 g of methyl methacrylate and measure 2 mL of dioxane into a vial and allow to dissolve.</li>
	<li>Prepare a stock solution of pure azobisisobutyronitrile (AIBN, 10 mg in 1.0 mL) and pipette in 139 &#956;L into the reaction mixture. Transfer to an ampoule equipped with a stir bar and seal.</li>
	<li>Freeze-pump-thaw the solution three times. Backfill with nitrogen and place the ampoule in a preheated oil bath at 65 &#176;C for 4 h. 
	NOTE: Do not heat the container with anything more than 30 &#176;C before the freeze-pump-thaw cycles are complete, as this can cause the initiator to decompose.</li>
	<li>To monitor conversion, remove the ampoule from the oil bath. Switch the cap for a suba seal under a flow of nitrogen, remove two drops and mix with deuterated chloroform. Run a proton spectrum on an NMR instrument.</li>
	<li>Place the ampoule in liquid nitrogen until frozen and open the ampoule to air to quench the polymerization.</li>
	<li>Precipitate the mixture dropwise into a vast excess of cold diethyl ether. Isolate by Buchner filtration and dry.</li>
	<li>Take the polymer up in THF and precipitate twice more. Dry the polymer thoroughly and analyze by 1H NMR spectroscopy and gel permeation chromatography (GPC).</li>
	<li>Follow this procedure again, but with 0.5 g of PCL-PMMA, 1.406 g of DMA, 2.0 mL of dioxane and 111 &#956;L of 10 mg.mL-1 AIBN in dioxane. Heat the polymerization at 70 &#176;C for 1 h and precipitate the reaction mixture into cold diethyl ether three times.</li>
</ol>
6. Self-nucleation, seed generation and living crystallization-driven self-assembly
<ol>
	<li>Place 5.0 mg of triblock copolymer into a vial and add 1.0 mL of ethanol. Seal the vial with a lid and parafilm and heat at 70 &#176;C for 3 h.</li>
	<li>Leave the vial to cool slowly to room temperature. Leave the solution to age at room temperature for two weeks. The solution will turn cloudy and will form a distinct layer at the bottom when fully assembled.</li>
	<li>Dilute the 5.0 mg.mL-1 dispersion to 1.0 mg.mL-1.</li>
	<li>Place the dispersion in a sonication proof tube and place in an ice bath.</li>
	<li>Insert the tip of the sonication probe into the middle area of the dispersion.</li>
	<li>Sonicate the solution for fifteen cycles of 2 min at the lowest intensity, allowing to cool for 15 min before the next cycle.</li>
	<li>Take an aliquot of the 1.0 mg.mL-1 seed dispersion and dilute to 0.18 mg.mL-1.</li>
	<li>Prepare a solution of unimer in THF at 25 mg.mL-1. Add 32.8 &#956;L into the seed dispersion and gently shake to allow full dissolution.</li>
	<li>Leave the dispersion to age for three days with the lid slightly ajar so the THF can evaporate. This will produce cylinders of 500 nm in length if the starting seeds were 90 nm in length.</li>
</ol>

<ol>
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B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monodisperse+cylindrical+micelles+by+crystallization-driven+living+self-assembly.">Monodisperse cylindrical micelles by crystallization-driven living self-assembly.</a> Nature Chemistry. 2, 566 (2010).</li><li>Boott, C. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+the+Growth+Kinetics+for+the+Formation+of+Uniform+1D+Block+Copolymer+Nanoparticles+by+Living+Crystallization-Driven+Self-Assembly.">Probing the Growth Kinetics for the Formation of Uniform 1D Block Copolymer Nanoparticles by Living Crystallization-Driven Self-Assembly.</a> ACS Nano. 12 (9), 8920-8933 (2018).</li><li>G&#228;dt, T., Ieong, N. S., Cambridge, G., Winnik, M. 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C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precision+Epitaxy+for+Aqueous+1D+and+2D+Poly(&#949;-caprolactone)+Assemblies.">Precision Epitaxy for Aqueous 1D and 2D Poly(&#949;-caprolactone) Assemblies.</a> Journal of the American Chemical Society. 139 (46), 16980-16985 (2017).</li><li>Sun, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tuning+the+Size+of+Cylindrical+Micelles+from+Poly(l-lactide)-b-poly(acrylic+acid)+Diblock+Copolymers+Based+on+Crystallization-Driven+Self-Assembly.">Tuning the Size of Cylindrical Micelles from Poly(l-lactide)-b-poly(acrylic acid) Diblock Copolymers Based on Crystallization-Driven Self-Assembly.</a> Macromolecules. 46 (22), 9074-9082 (2013).</li><li>Fan, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crystallization-driven+one-dimensional+self-assembly+of+polyethylene-b-poly(tert-butylacrylate)+diblock+copolymers+in+DMF:+effects+of+crystallization+temperature+and+the+corona-forming+block.">Crystallization-driven one-dimensional self-assembly of polyethylene-b-poly(tert-butylacrylate) diblock copolymers in DMF: effects of crystallization temperature and the corona-forming block.</a> Soft Matter. 12 (1), 67-76 (2016).</li><li>He, W. -. N., Zhou, B., Xu, J. -. T., Du, B. -. Y., Fan, Z. -. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two+Growth+Modes+of+Semicrystalline+Cylindrical+Poly(&#949;-caprolactone)-b-poly(ethylene+oxide)+Micelles.">Two Growth Modes of Semicrystalline Cylindrical Poly(&#949;-caprolactone)-b-poly(ethylene oxide) Micelles.</a> Macromolecules. 45 (24), 9768-9778 (2012).</li><li>Patra, S. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cylindrical+Micelles+of+Controlled+Length+with+a+&#960;-Conjugated+Polythiophene+Core+via+Crystallization-Driven+Self-Assembly.">Cylindrical Micelles of Controlled Length with a &#960;-Conjugated Polythiophene Core via Crystallization-Driven Self-Assembly.</a> Journal of the American Chemical Society. 133 (23), 8842-8845 (2011).</li><li>Kynaston, E. L., Nazemi, A., MacFarlane, L. R., Whittell, G. R., Faul, C. F. J., Manners, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Uniform+Polyselenophene+Block+Copolymer+Fiberlike+Micelles+and+Block+Co-micelles+via+Living+Crystallization-Driven+Self-Assembly.">Uniform Polyselenophene Block Copolymer Fiberlike Micelles and Block Co-micelles via Living Crystallization-Driven Self-Assembly.</a> Macromolecules. 51 (3), 1002-1010 (2018).</li><li>Rizis, G., Mvan de Ven, T. G., Eisenberg, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crystallinity-driven+morphological+ripening+processes+for+poly(ethylene+oxide)-block-polycaprolactone+micelles+in+water.">Crystallinity-driven morphological ripening processes for poly(ethylene oxide)-block-polycaprolactone micelles in water.</a> Soft Matter. 10 (16), 2825-2835 (2014).</li><li>Jin, X. -. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-range+exciton+transport+in+conjugated+polymer+nanofibers+prepared+by+seeded+growth.">Long-range exciton transport in conjugated polymer nanofibers prepared by seeded growth.</a> Science. 360 (6391), (2018).</li><li>Rizis, G., van&#8197;de&#8197;Ven, T. G. M., Eisenberg, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=&#8220;Raft&#8221;+Formation+by+Two-Dimensional+Self-Assembly+of+Block+Copolymer+Rod+Micelles+in+Aqueous+Solution.">&#8220;Raft&#8221; Formation by Two-Dimensional Self-Assembly of Block Copolymer Rod Micelles in Aqueous Solution.</a> Angewandte Chemie International Edition. 53 (34), 9000-9003 (2014).</li><li>Qiu, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Uniform+patchy+and+hollow+rectangular+platelet+micelles+from+crystallizable+polymer+blends.">Uniform patchy and hollow rectangular platelet micelles from crystallizable polymer blends.</a> Science. 352 (6286), 701 (2016).</li><li>Zhou, H., Lu, Y., Yu, Q., Manners, I., Winnik, M. 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The authors have nothing to disclose.

The synthesis and living CDSA of the triblock copolymer PCL50-PMMA10-PDMA200 has been outlined. Although stringent conditions are required, the ring-opening polymerization of &#949;-caprolactone gave polymers with excellent properties that enabled the successful chain extensions of MMA and DMA. These polymers were successful in their self-seeding, obtaining a pure phase of cylindrical micelles, which were sonicated into seed particles of LN 98 nm. Through simple addition of unimer, cylinders with average lengths ranging up to 495 nm were produced in a controlled manner. A triblock terpolymer is used over a diblock copolymer in this instance. This overcomes fragmentation issues when the cylinders are transferred to water. It has been previously reported that the incorporation of a stabilizing short block with a high glass transition temperature can prevent the cylinders from fracturing.

However, deviation from the protocols can result in polymers that are unfit for CDSA applications. For example, it is very important that the monomer must be added to the initiator/catalyst solution, not vice versa in ROP. This ensures that all initiation events occur within the same time window and a polymer of low dispersity is obtained. The importance of effective reagent drying procedures relative to the success of ring opening polymerizations has been continually outlined throughout this manuscript.

There are also common pitfalls encountered in RAFT polymerizations. Judging the conversion by time alone will result in an incorrect degree of polymerization. A multitude of factors can cause the kinetics to differ day to day (pump vacuum, volume of headspace and purity of initiator for example). Thus, it is recommended that when aiming for specific conversions, the polymerization is monitored by 1H NMR spectroscopy throughout. Precipitations must be carried out with solutions containing 20 wt% of polymer or less, otherwise purification is not effective. Albeit simple, minor changes to the self-assembly protocol can induce significant loss of uniformity in the samples. For example, if the volume of the unimer solution is too high, THF can plasticize the crystalline core and induce a phase change to a plate like geometry. Similar artifacts can be observed if the concentrations of the unimer solution (&#62; 100 mg.mL-1) or the seed-dispersion (&#62;5 mg.mL-1) are too high.

This manuscript has highlighted the protocols and nuances of a variety of polymerization techniques in the context of CDSA, in the hope that others will be able to reproduce the results and continue research into this exciting field. The translation of these methods to other, more application-driven ideas is of paramount importance to both the authors and the scientific community at large.&#160;

One-dimensional (1D) nanostructures, such as cylinders, fibers and tubes, have garnered increasing attention in a variety of fields. Amongst these, their popularity in polymer science is owed to their rich variety of properties. For example, Geng et al. demonstrated that filomicelles exhibit a tenfold increase in residence time in the bloodstream of a rodent model compared to their spherical counterparts, and Won et al. revealed that polybutadiene-b-poly(ethylene oxide) fiber dispersions display an increase in storage modulus by two orders of magnitude upon crosslinking of the core during rheological measurements1,2. Interestingly, many of these systems are synthesized via the self-assembly of block copolymers, whether this be through more traditional methods of solvent switching and thin-film rehydration3, or more advanced methods such as polymerization-induced self-assembly and crystallization-driven self-assembly (CDSA)4,5. Each technique holds their own advantages, however, only CDSA can produce rigid particles with a uniform and controllable length distribution.
Pioneering work by Gilroy et al. formed long polyferrocenylsilane-b-polydimethylsiloxane (PFS-PDMS) cylinders in hexanes and, when using mild sonication, very short cylinders with a low contour length dispersity (Ln). Upon the addition of a predetermined mass of diblock copolymer chains in a common solvent, cylinders of varying lengths with an Ln as low as 1.03 were synthesised5,6. Further work by the Manners group highlighted the high degree of control possible with the PFS system, which may be used to form remarkably complex and hierarchal structures: block-co-micelles, scarf shaped and dumbbell micelles to name a few7,8. Following these demonstrations, researchers investigated other, more functional systems for CDSA including: semi-crystalline commodity polymers (polyethylene, poly(&#949;-caprolactone), polylactide)9,10,11,12,13 and conducting polymers (poly(3-hexylthiophene), polyselenophene)14,15. Armed with this toolbox of diblock copolymer systems that can be assembled quickly and efficiently, researchers have carried out more application-driven research in recent years16.&#160; Jin et al. have demonstrated exciton diffusion lengths in the hundreds of nanometers in polythiophene block copolymers and our group demonstrated the formation of gels from poly(&#949;-caprolactone) (PCL) containing cylindrical constructs10,17.
Although it is a powerful technique, CDSA does have its limitations. The block copolymers must have a semi-crystalline component, as well as low dispersity values and high end group fidelities; lower order block contaminants may cause particle aggregation or induce morphology changes18,19. Due to these restrictions, living polymerizations are used. However, significant reagent purification, drying procedures and water/oxygen free environments are required in order to achieve polymers with the aforementioned properties. Attempts have been made to design systems that overcome this. For example, PFS block copolymers have been formed using click chemistry to couple polymer chains together20. Although the resulting cylindrical nanoparticles have demonstrated exemplary properties, the block copolymers are typically purified by preparative size exclusion chromatography and the synthesis of PFS still requires the use of living anionic polymerizations. Our group recently realized the living CDSA of PCL, the success of which revolved around using both living organobase-catalyzed ring-opening polymerizations (ROP) and reversible addition-fragmentation chain transfer (RAFT) polymerizations10. Although this method is simpler, living polymerizations are still required.
As the field is moving towards more application-driven research, and due to the problems associated with living polymerizations, it is believed that an outline of the polymer synthesis and self-assembly protocols will be advantageous to future scientific work. Thus, in this manuscript, the complete synthesis and self-assembly of a PCL-b-PMMA-b-PDMA copolymer is outlined. Drying techniques will be highlighted in the context of an organocatalyzed ROP of &#949;-caprolactone and the subsequent RAFT polymerizations of MMA and DMA will be outlined. Finally, a living CDSA protocol for this polymer in ethanol will be presented and common errors in characterization data due to poor experimental technique will be critiqued.

<table>
	<tbody>
		<tr>
			<td>2,2&#39;-azobisisobutyrnitrile</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>250 mL ampoule</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>250 mL two neck RBF</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ampoule (25 mL)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>B19 tap</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>B24 stopper</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Basic Alumina</td>
			<td>Fluka</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Buchner Flask</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Buchner Funnel</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Caclium Hydride</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cannulae</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>caprolactone</td>
			<td>Arcos Organics</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Chain Transfer Agent</td>
			<td>Made in House</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Conical Flask (multiple sizes)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dessicator</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Diethyl Ether</td>
			<td>Merck</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dioxane</td>
			<td>Fisher</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>diphenylphosphate</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Distillation Condenser</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Fisher</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Filter Paper (multiple sizes)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gel Permeation Chrmoatography Instrument</td>
			<td>Agilent Technologies Infinity 1260 II</td>
			<td></td>
			<td>Running DMF at 50 &#176;C</td>
		</tr>
		<tr>
			<td>Glovebox</td>
			<td>Mbraun, Unilab</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hotplate</td>
			<td>IKA, RCT basic</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Mercury Thermometer</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Methyl Methacrylate</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Molecular seives</td>
			<td>Fisher</td>
			<td>MS/1030/53</td>
			<td></td>
		</tr>
		<tr>
			<td>N,N-dimethyl acrylamide</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NMR spectrometer</td>
			<td>Bruker 400 MHz</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphorus pentoxide</td>
			<td>Sigma Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>RBF (multiple sizes)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Schlenk Cap (B24)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Schlenk Flask (250 mL)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Schlenk Line</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sonication Probe</td>
			<td>Bandelin Sonoplus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Suba Seal (multiple sizes)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>TEM grids</td>
			<td>EmResolutions, Formvar/carbon film 300 mesh copper</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>THF</td>
			<td>Merck</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>three neck adaptor</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Toluene</td>
			<td>Fisher</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Transmission Electron Microscope</td>
			<td>Jeol 2100</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

synthesis of monodisperse cylindrical nanoparticles via crystallization-driven self-assembly of biodegradable block copolymers

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock copolymers are produced by one of three techniques: thin film rehydration, solvent switching or polymerization-induced self-assembly, and produce only flexible, polydisperse cylinders. Crystallization-driven self-assembly (CDSA) is a method which can produce cylinders with these properties, by stabilizing structures of a lower curvature due to the formation of a crystalline core. However, the living polymerization techniques by which most core-forming blocks are formed are not trivial processes and the CDSA process may yield unsatisfactory results if carried out incorrectly. Here, the synthesis of cylindrical nanoparticles from simple reagents is shown. The drying and purification of reagents prior to a ring-opening polymerization of &#949;-caprolactone catalyzed by diphenyl phosphate is described. This polymer is then chain extended by methyl methacrylate (MMA) followed by N,N-dimethyl acrylamide (DMA) using reversible addition&#8722;fragmentation chain-transfer (RAFT) polymerization, affording a triblock copolymer that can undergo CDSA in ethanol. The living CDSA process is outlined, the results of which yield cylindrical nanoparticles up to 500 nm in length and a length dispersity as low as 1.05. It is anticipated that these protocols will allow others to produce cylindrical nanostructures and elevate the field of CDSA in the future.

PCL was analyzed by 1H NMR spectroscopy and gel permeation chromatography (GPC). The 1H NMR spectrum yielded a degree of polymerization (DP) of 50, by comparison of resonances at 3.36 ppm and 4.08 ppm, which correspond to the end group ethyl protons and the in-chain ester &#945;-protons respectively (Figure 1b). This provided validation of the molecular weight values obtained by GPC where a single peak, with a dispersity value of 1.07, was observed with an Mn of 10,800 g.mol-1 (Figure 1c). A polymerization using reagents that had not been correctly dried yielded a product mixture which included oligomeric or low molecular weight PCL, as demonstrated by the trace which includes a low molecular weight tail (Figure 1d). This behavior is due to spurious initiation by water. By comparison, a properly dried polymerization that was left to react for 12h (that is, 4 h at conversions above 95%) gave a high molecular weight shoulder at 15,500 g.mol-1, due to transesterification between polymer chains (Figure 1e).
The successive RAFT polymerizations were characterized by the same techniques. The 1H NMR spectrum of the PCL-PMMA indicated a DP of 10 (of the PMMA block) by comparison of the PCL in-chain ester &#945;-protons (4.08 ppm) and the methyl &#945;-protons of PMMA (3.62 ppm, Figure 2b). The GPC trace displayed a unimodal peak (Figure 2c), however, when deliberately taken to too high conversions (&#62;70%) a broadening of molecular weight and a high molecular weight shoulder was observed, most likely due to disproportionation side reactions (Figure 2d). The DP of the final block of PDMA was 200 upon comparison of the PCL in chain ether protons (4.08 ppm) and the DMA side chain methyl protons (2.93 ppm, Figure 3b). Again, the GPC trace was narrow and unimodal (Figure 3c). Upon repetition of the chain extension using impure PCL-PMMA, a low molecular weight shoulder appears (Figure 3d). This is a manifestation of a larger concentration of initiator in the polymerization, which results in a larger proportion of initiator derived chains being produced.
The self-nucleation process (the first step in a living CDSA) generated structures that were observed by transmission electron microscopy (TEM). Images collected after three days of aging displayed high-aspect ratio cylindrical particles accompanied by a sub-population of spheres (Figure 4a). The latter are unimer chains which have not yet grown onto the cylinders. Upon aging for a further ten days, a pure phase of cylinders was observed (Figure 4b). Sonication of the long cylinders caused them to fragment, yielding small cylindrical particles (seeds) with, upon examination of at least 300 particles by TEM, an average contour length of 90 nm with a dispersity of 1.15 (Figure 4c). These seeds were used to generate populations of cylinders with increasingly longer contour length by the simple addition of polymer chains (unimer) in a common solvent (Figure 5b-g). Interestingly, when LN of the particles is plotted against the mass ratio of unimer to seeds, a linear trend is observed (Figure 5i). Further analysis of these particles by TEM indicates incredible uniformity over all the samples (Figure 5h).
Multiple issues can arise during living CDSA. Repetition of the self-nucleation process with a triblock copolymer that has a low molecular weight tail results in the observation of a population of plate-like structures (Figure 6a). If total sonication times exceed 30 min or cycle times are in excess of 2 min, the uniformity of the cylinders suffers greatly (Figure 6b). This is due to a small proportion of polymer dissolving from the particles (either due to the formation of extremely small, unstable particles, or through heating of the particle dispersion) and recrystallizing onto the remaining cylinders. Finally, the volume of common solvent added during the cylinder extension step can cause plate-like structures to be observed by TEM (Figure 6c).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/59772/59772fig1.jpg" /> 
Figure 1: Typical results from a ring-opening polymerization of &#949;-caprolactone. (a) The reaction scheme of the synthesis of PCL50, (b) the 1H NMR spectrum displaying the resonances that are used to calculate DP and (c) a typical molecular weight distribution, (d) a molecular weight distribution of an ROP that contains trace water and (e) a molecular weight distribution of an ROP that has reacted for too long. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59772/59772fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/59772/59772fig2.jpg" /> 
Figure 2: Typical results from a RAFT polymerization of methyl methacrylate. (a) The reaction scheme of the synthesis of PCL50-PMMA10, (b) the 1H NMR spectrum displaying the resonances that are used to calculate DP and (c) a typical molecular weight distribution of a good RAFT polymerization of MMA, (d) a typical molecular weight distribution of a RAFT polymerization of MMA that has been taken to too high conversion. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59772/59772fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/59772/59772fig3.jpg" /> 
Figure 3: Typical results from a RAFT polymerization of N,N-dimethylacrylamide. (a) The reaction scheme of the synthesis of PCL50-PMMA10-PDMA200 , (b) the 1H NMR spectrum displaying the resonances that are used to calculate DP and (c) a typical molecular weight distribution of a good RAFT polymerization of DMA, (d) a typical molecular weight distribution of a RAFT polymerization of DMA that was incorrectly purified in the previous step. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59772/59772fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/59772/59772fig4.jpg" /> 
Figure 4: Preparation of triblock copolymer seed nanoparticles. TEM images of a 5 mg.mL-1 dispersion of PCL50-PMMA10-PDMA200 having aged for (a) three days, (b) two weeks and (c) after 15 x 2 min of sonication cycles. Scale bars are 500 nm, 100 nm and 1000 nm, respectively.&#160; <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59772/59772fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/59772/59772fig5.jpg" /> 
Figure 5: Living crystallization-driven self-assembly from seeds. (a) Scheme depicting the sonication and living CDSA of the triblock copolymer, (b-g) TEM images of the living CDSA up to 500 nm, (h) the properties of the particles and (i) the relationship between the average length of the micelles and seed/unimer mass ratio. Figure reproduced from Arno, M. C., Inam, M., et al. Precision Epitaxy for Aqueous 1D and 2D Poly(&#949;-caprolactone) Assemblies. Journal of the American Chemical Society 139, (46)16980&#8211;16985 (2017). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59772/59772fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/59772/59772fig6.jpg" /> 
Figure 6: Troubleshooting CDSA of the Triblock Copolymer. TEM images of structures (a) formed by CDSA of a triblock copolymer with a low molecular weight shoulder, (b) formed by the incorrect sonication of long cylinders and (c) formed by the addition of a high volume of common solvent to the seed dispersion. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59772/59772fig6large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers at JoVE.com

Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers

Crystallization-driven self-assembly (CDSA) displays the unique ability to fabricate cylindrical nanostructures of narrow length distributions. The organocatalyzed ring-opening polymerization of &#949;-caprolactone and subsequent chain extensions of methyl methacrylate and N,N-dimethyl acrylamide are demonstrated. A living CDSA protocol that produces monodisperse cylinders up to 500 nm in length is outlined.

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock ...

synthesis-monodisperse-cylindrical-nanoparticles-via-crystallization

Nanyang Technological University

Research

JoVE Journal

Chemistry

7.7K Views.  University of Birmingham. Crystallization-driven self-assembly (CDSA) displays the unique ability to fabricate cylindrical nanostructures of narrow length distributions. The organocatalyzed ring-opening polymerization of ε-caprolactone and subsequent chain extensions of methyl methacrylate and N,N-dimethyl acrylamide are demonstrated. A living CDSA protocol that produces monodisperse cylinders up to 500 nm in length is outlined.

Video: Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers

Origami Inspired Self-assembly of Patterned and Reconfigurable Particles

There are numerous techniques such as photolithography, electron-beam lithography and soft-lithography that can be used to precisely pattern two dimensional (2D) structures. These technologies are mature, offer high precision and many of them can be implemented in a high-throughput manner. We leverage the advantages of planar lithography and combine them with self-folding methods1-20 wherein physical forces derived from surface tension or residual stress, are used to curve or fold planar structures into three dimensional (3D) structures. In doing so, we make it possible to mass produce precisely patterned static and reconfigurable particles that are challenging to synthesize.
In this paper, we detail visualized experimental protocols to create patterned particles, notably, (a) permanently bonded, hollow, polyhedra that self-assemble and self-seal due to the minimization of surface energy of liquefied hinges21-23 and (b) grippers that self-fold due to residual stress powered hinges24,25. The specific protocol described can be used to create particles with overall sizes ranging from the micrometer to the centimeter length scales. Further, arbitrary patterns can be defined on the surfaces of the particles of importance in colloidal science, electronics, optics and medicine. More generally, the concept of self-assembling mechanically rigid particles with self-sealing hinges is applicable, with some process modifications, to the creation of particles at even smaller, 100 nm length scales22, 26 and with a range of materials including metals21, semiconductors9 and polymers27. With respect to residual stress powered actuation of reconfigurable grasping devices, our specific protocol utilizes chromium hinges of relevance to devices with sizes ranging from 100 &mu;m to 2.5 mm. However, more generally, the concept of such tether-free residual stress powered actuation can be used with alternate high-stress materials such as heteroepitaxially deposited semiconductor films5,7 to possibly create even smaller nanoscale grasping devices.

We describe experimental details of the synthesis of patterned and reconfigurable particles from two dimensional (2D) precursors. This methodology can be used to create particles in a variety of shapes including polyhedra and grasping devices at length scales ranging from the micro to centimeter scale.

There are numerous techniques such as photolithography, electron-beam lithography and soft-lithography that can be used to precisely pattern two ...

Formation of Ordered Biomolecular Structures by the Self-assembly of Short Peptides

In nature, complex functional structures are formed by the self-assembly of biomolecules under mild conditions. Understanding the forces that control self-assembly and mimicking this process in vitro will bring about major advances in the areas of materials science and nanotechnology. Among the available biological building blocks, peptides have several advantages as they present substantial diversity, their synthesis in large scale is straightforward, and they can easily be modified with biological and chemical entities1,2. Several classes of designed peptides such as cyclic peptides, amphiphile peptides and peptide-conjugates self-assemble into ordered structures in solution. Homoaromatic dipeptides, are a class of short self-assembled peptides that contain all the molecular information needed to form ordered structures such as nanotubes, spheres and fibrils3-8. A large variety of these peptides is commercially available.
This paper presents a procedure that leads to the formation of ordered structures by the self-assembly of homoaromatic peptides. The protocol requires only commercial reagents and basic laboratory equipment. In addition, the paper describes some of the methods available for the characterization of peptide-based assemblies. These methods include electron and atomic force microscopy and Fourier-Transform Infrared Spectroscopy (FT-IR). Moreover, the manuscript demonstrates the blending of peptides (coassembly) and the formation of a &#34;beads on a string&#34;-like structure by this process.9 The protocols presented here can be adapted to other classes of peptides or biological building blocks and can potentially lead to the discovery of new peptide-based structures and to better control of their assembly.

This paper describes the formation of highly ordered peptide-based structures by the spontaneous process of self-assembly. The method utilizes commercially available peptides and common lab equipment. This technique can be applied to a large variety of peptides and may lead to the discovery of new peptide-based assemblies.

In nature, complex functional structures are formed by the self-assembly of biomolecules under mild conditions. Understanding the forces that control ...

Functionalization of Single-walled Carbon Nanotubes with Thermo-reversible Block Copolymers and Characterization by Small-angle Neutron Scattering

We demonstrate a protocol for single-walled carbon nanotube functionalization using thermo-sensitive PEO-PPO-PEO triblock copolymers in an aqueous solution. In a carbon nanotube/PEO105-PPO70-PEO105 (poloxamer 407) aqueous solution, the amphiphilic poloxamer 407 adsorbs onto the carbon nanotube surfaces and self-assembles into continuous layers, driven by intermolecular interactions between constituent molecules. The addition of 5-methylsalicylic acid changes the self-assembled structure from spherical-micellar to a cylindrical morphology. The fabricated poloxamer 407/carbon nanotube hybrid particles exhibit thermo-responsive structural features so that the density and thickness of poloxamer 407 layers are also reversibly controllable by varying temperature. The detailed structural properties of the poloxamer 407/carbon nanotube particles in suspension can be characterized by small-angle neutron scattering experiments and model fit analyses. The distinct curve shapes of the scattering intensities depending on temperature control or addition of aromatic additives are well described by a modified core-shell cylinder model consisting of a carbon nanotube core cylinder, a hydrophobic shell, and a hydrated polymer layer. This method can provide a simple but efficient way for the fabrication and in-situ characterization of carbon nanotube-based nano particles with a structure-tunable encapsulation.

A method for the functionalization of carbon nanotubes with structure-tunable polymeric encapsulation layers and structural characterization using small-angle neutron scattering is presented.

We demonstrate a protocol for single-walled carbon nanotube functionalization using thermo-sensitive PEO-PPO-PEO triblock copolymers in an aqueous ...

Synthesis of Ligand-free CdS Nanoparticles within a Sulfur Copolymer Matrix

Aliphatic ligands are typically used during the synthesis of nanoparticles to help mediate their growth in addition to operating as high-temperature solvents. These coordinating ligands help solubilize and stabilize the nanoparticles while in solution, and can influence the resulting size and reactivity of the nanoparticles during their formation. Despite the ubiquity of using ligands during synthesis, the presence of aliphatic ligands on the nanoparticle surface can result in a number of problems during the end use of the nanoparticles, necessitating further ligand stripping or ligand exchange procedures. We have developed a way to synthesize cadmium sulfide (CdS) nanoparticles using a unique sulfur copolymer. This sulfur copolymer is primarily composed of elemental sulfur, which is a cheap and abundant material. The sulfur copolymer has the advantages of operating both as a high temperature solvent and as a sulfur source, which can react with a cadmium precursor during nanoparticle synthesis, resulting in the generation of ligand free CdS. During the reaction, only some of the copolymer is consumed to produce CdS, while the rest remains in the polymeric state, thereby producing a nanocomposite material. Once the reaction is finished, the copolymer stabilizes the nanoparticles within a solid polymeric matrix. The copolymer can then be removed before the nanoparticles are used, which produces nanoparticles that do not have organic coordinating ligands. This nascent synthesis technique presents a method to produce metal-sulfide nanoparticles for a wide variety of applications where the presence of organic ligands is not desired.

Herein we present a method to synthesize ligand-free cadmium sulfide (CdS) nanoparticles based on a unique sulfur copolymer. The sulfur copolymer operates as a high temperature solvent and a sulfur source during the nanoparticle synthesis and stabilizes the nanoparticles after the reaction.

Aliphatic ligands are typically used during the synthesis of nanoparticles to help mediate their growth in addition to operating as high-temperature ...

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the development of antibody drug conjugates (ADCs) and nanomedicine, fluorescent microscopy and systems chemistry. For many of these applications, specificity of the bioconjugation method used is of prime concern. The Michael addition of maleimides with cysteine(s) on the target proteins is highly selective and proceeds rapidly under mild conditions, making it one of the most popular methods for protein bioconjugation.
We demonstrate here the modification of the only surface-accessible cysteine residue on yeast cytochrome c with a ruthenium(II) bisterpyridine maleimide. The protein bioconjugation is verified by gel electrophoresis and purified by aqueous-based fast protein liquid chromatography in 27% yield of isolated protein material. Structural characterization with MALDI-TOF MS and UV-Vis is then used to verify that the bioconjugation is successful. The protocol shown here is easily applicable to other cysteine - maleimide coupling of proteins to other proteins, dyes, drugs or polymers.

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

This protocol details the important steps required for the bioconjugation of a cysteine containing protein to a maleimide, including reagent purification, reaction conditions, bioconjugate purification and bioconjugate characterization.

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the ...

Liquid-cell Transmission Electron Microscopy for Tracking Self-assembly of Nanoparticles

Drying a nanoparticle dispersion is a versatile way to create self-assembled structures of nanoparticles, but the mechanism of this process is not fully understood. We have traced the trajectories of individual nanoparticles using liquid-cell transmission electron microscopy (TEM) to investigate the mechanism of the assembly process. Herein, we present the protocols used for liquid-cell TEM studies of the self-assembly mechanism. First, we introduce the detailed synthetic protocols used to produce uniformly sized platinum and lead selenide nanoparticles. Next, we present the microfabrication processes used to produce liquid cells with silicon nitride or silicon windows and then describe the loading and imaging procedures of the liquid-cell TEM technique. Several notes are included to provide helpful tips for the entire process, including how to manage the fragile cell windows. The individual motions of nanoparticles tracked by liquid-cell TEM revealed that changes in the solvent boundaries caused by evaporation affected the self-assembly process of nanoparticles. The solvent boundaries drove nanoparticles to primarily form amorphous aggregates, followed by flattening of the aggregates to produce a 2-dimensional (2D) self-assembled structure. These behaviors are also observed for different nanoparticle types and different liquid-cell compositions.

Here we introduce experimental protocols for the real-time observation of a self-assembly process using liquid-cell transmission electron microscopy.

Drying a nanoparticle dispersion is a versatile way to create self-assembled structures of nanoparticles, but the mechanism of this process is not fully ...

Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and porous metal-dithiolene network in the highly ordered single crystalline state. Unlike the highly reactive free-standing thiols, which tend to decompose and complicate the crystallization of metal-thiolate open frameworks, the thioester reacts in situ to provide the thiol species, serving to mitigate the reaction between the mercaptan units and the metal centers, and to improve crystallization consequently. Specifically, the thioester was synthesized in a one-pot procedure: an aromatic bromide (hexabromotriphenylene) reacted with excess sodium thiomethoxide under vigorous conditions to first form the thioether intermediate product. The thioether was then demethylated by the excess thiomethoxide to provide the thiolate anion that was acylated to form the thioester product. The thioester was conveniently purified by standard column chromatography, and then used directly in the framework synthesis, wherein NaOH and ethylenediamine serve to revert in situ the thioester to the thiol linker for assembling the single-crystalline Pb(II)-dithiolene network. Compared with other methods for thiol synthesis (e.g., by cleaving alkyl thioether using sodium metal and liquid ammonia), the thioester synthesis here uses simple conditions and economical reagents. Moreover, the thioester product is stable and can be conveniently handled and stored. More importantly, in contrast to the generic difficulty in accessing crystalline metal-thiolate open frameworks, we demonstrate that using the thioester for in situ formation of the thiol linker greatly improves the crystallinity of the solid-state product. We intend to encourage broader research efforts on the technologically important metal-sulfur frameworks by disclosing the synthetic protocol for the thioester as well as the crystalline framework solid.

Here, we present a one-pot, transition-metal-free synthesis of thiols and thioesters from aromatic halides and sodium thiomethoxide, followed by the preparation of single crystals of a metal-dithiolene network using thiol species generated in situ from the more stable and tractable thioester.

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and ...

Synthesis of Substrate-Bound Au Nanowires Via an Active Surface Growth Mechanism

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a challenge, as it requires asymmetric growth of symmetric crystals. Here, we report a distinctive synthesis of substrate-bound Au nanowires. This template-free synthesis employs thiolated ligands and substrate adsorption to achieve the continuous asymmetric deposition of Au in solution at ambient conditions. The thiolated ligand prevented the Au deposition on the exposed surface of the seeds, so the Au deposition only occurs at the interface between the Au seeds and the substrate. The side of the newly deposited Au nanowires is immediately covered with the thiolated ligand, while the bottom facing the substrate remains ligand-free and active for the next round of Au deposition. We further demonstrate that this Au nanowire growth can be induced on various substrates, and different thiolated ligands can be used to regulate the surface chemistry of the nanowires. The diameter of the nanowires can also be controlled with mixed ligands, in which another &#34;bad&#34; ligand could turn on the lateral growth. With the understanding of the mechanism, Au nanowire-based nanostructures can be designed and synthesized.

We report a solution-based method to synthesize substrate-bound Au nanowires. By tuning the molecular ligands used during the synthesis, the Au nanowires can be grown from various substrates with different surface properties. Au nanowire-based nanostructures can also be synthesized by adjusting the reaction parameters.

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a ...

Synthesis of Bimetallic Pt/Sn-based Nanoparticles in Ionic Liquids

We demonstrate a method for the synthesis of bimetallic nanoparticles consisting of Pt and Sn. A synthesis strategy is used in which the particular physico-chemical properties of ionic liquids (ILs) are exploited to control both nucleation and growth processes. The nanoparticles form colloidal sols of very high colloidal stability in the IL, which is particularly interesting in view of their use as quasi-homogeneous catalysts. Procedures for both nanoparticle extraction in conventional solvents and for nanoparticle precipitation are presented. The size, structure and composition of the synthesized nanocrystals are confirmed using inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDX). By this, we show that the nanocrystals are random-type alloy and of small (2-3 nm) size. The catalytic activity and selectivity in the hydrogenation of &#945;,&#946;-unsaturated aldehydes is tested in a semi-continuous batch-type reactor. In this context, the bimetallic Pt/Sn-based nanoparticles reveal a high selectivity towards the unsaturated alcohol.

A protocol for the synthesis of bimetallic nanoparticles in ionic liquids and the procedure of their catalytic testing in the selective hydrogenation of unsaturated aldehydes are described.

We demonstrate a method for the synthesis of bimetallic nanoparticles consisting of Pt and Sn. A synthesis strategy is used in which the particular ...

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles

The development of feasible synthesis methods is critical for the successful exploration of novel properties and potential applications of nanomaterials. Here, we introduce the molten-salt synthesis (MSS) method for making metal oxide nanomaterials. Advantages over other methods include its simplicity, greenness, reliability, scalability, and generalizability. Using pyrochlore lanthanum hafnium oxide (La2Hf2O7) as a representative, we describe the MSS protocol for the successful synthesis of complex metal oxide nanoparticles (NPs). Furthermore, this method has the unique ability to produce NPs with different material features by changing various synthesis parameters such as pH, temperature, duration, and post-annealing. By fine-tuning these parameters, we are able to synthesize highly uniform, non-agglomerated, and highly crystalline NPs. As a specific example, we vary the particle size of the La2Hf2O7&#160;NPs by changing the concentration of the ammonium hydroxide solution used in the MSS process, which allows us to further explore the effect of particle size on various properties. It is expected that the MSS method will become a more popular synthesis method for nanomaterials and more widely employed in the nanoscience and nanotechnology community in the upcoming years.

Here, we demonstrate a unique, relatively low-temperature, molten-salt synthesis method for preparing uniform complex metal oxide lanthanum hafnate nanoparticles.

The development of feasible synthesis methods is critical for the successful exploration of novel properties and potential applications of nanomaterials. ...