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Attenzione: Si prega di indossare un camice da laboratorio, guanti e occhiali di sicurezza e leggere le schede di sicurezza (MSDS) prima dell'uso. Tutti i materiali acquistati sono stati utilizzati senza ulteriore purificazione.
1. preparazione di emulsioni costituite da miscele di SDS stirene/PFO/acquoso soluzione
<ol><li>Per preparare 5 mM di soluzione acquosa di SDS, sciogliere 14,5 mg di SDS in 10 mL di elevata purezza H2O. Nota: È stato utilizzato ad alta purezza H2O (resistività (R) = 18 cm MΩ, tensione superficiale (γ) = 72,0 mN m-1 a 25 ° C).</li>
	<li>Aggiungere 1,5 g di stirene, 0,6 g di PFO e 0,9 g di 5 mM di soluzione acquosa di SDS per un flaconcino di vetro da 10 mL con un'ancoretta. Nota: Nella scansione osservazioni di microscopia di fluorescenza confocale, aggiungere 2,6 mg di cumarina 102 e 0,062 mg di calceina alla miscela.</li>
	<li>Mescolare l'impasto per 60 min a 1.150 giri sotto temperatura ambiente e quindi aumentare la temperatura a 80 ° C.</li>
	<li>Mescolare l'impasto per 60 min a 1.150 giri e 80 ° C.</li>
</ol>2. fabbricazione di particelle di polimero usando emulsioni consistenti di stirene/PFO/acquoso SDS soluzione miscele
<ol><li>Aggiungere un flaconcino di vetro da 10 mL con un'ancoretta 3,9 mg di potassio Perossidisolfato, 2 mg di pirene, 1,5 g di stirene, 0,6 g di PFO e 0,9 g di 5 mM di soluzione acquosa di SDS e sigillare con un setto di gomma.</li>
	<li>Deoxygenate la miscela di gas di azoto bubbling attraverso un ago di siringa per 30 min. Attenzione: Lentamente il flusso del gas di azoto per non generare una grande quantità di schiuma.</li>
	<li>Per preparare l'emulsione, mescolare l'impasto per 60 min a 1.150 giri e temperatura ambiente e quindi aumentare la temperatura a 80 ° C.</li>
	<li>Mescolare il composto per 30 min a 1.150 giri e 80 ° C.</li>
	<li>Trasferire la parte nuvolosa (1,8 mL) della soluzione risultante (3ml) alla provetta e quindi aggiungere la soluzione acquosa di etanolo al 30% per terminare completamente la reazione di polimerizzazione.</li>
	<li>Sottoporre ad ultrasuoni (potenza: 130 W, frequenza: 4,2 kHz) per 10 min a lavare le particelle di polimero risultante e poi Centrifugare per 10 min a 2300 x g.</li>
	<li>Per ottenere le particelle di polimero, è necessario rimuovere il supernatante dalla provetta.</li>
	<li>Aggiungere 3 mL di acqua per i solidi risultanti nella provetta. Sottoporre ad ultrasuoni (potenza: 130 W, frequenza: 4,2 kHz) per 10 min e centrifugare per 10 min 2300 g. x rimuovere il supernatante dalla provetta.</li>
	<li>Ripetere la procedura di lavaggio (passo 2,8) fino a quando la schiuma non viene generato dalla soluzione surnatante. Evaporare l'acqua per ottenere il solido di particelle di polimero hollow.</li>
</ol>3. preparazione di microcapsule usando le particelle di polimero cava
<ol><li>Aggiungere 1 mg di particelle di polistirene hollow (punto 2.9) e 4 mL di acqua per un flaconcino di vetro da 10 mL con un'ancoretta.</li>
	<li>Sottoporre ad ultrasuoni (potenza: 130 W, frequenza: 4,2 kHz) per 10 min disperdere le particelle vuote in acqua.</li>
	<li>Aggiungere 0,1 mL di toluene all'acqua disperse le particelle e poi mescolare per 1 h a 100 giri/min a temperatura ambiente. Trasferire il liquido in una provetta. Attenzione: Se la rotazione al minuto aumenta, la morfologia delle particelle si deformerà.</li>
	<li>Centrifugare il liquido per 10 min a 2300 x g per isolare le microcapsule si formano. Rimuovere il supernatante dalla provetta.</li>
</ol>

<ol>
	<li>Okubo, M., Fujibayashi, T., Terada, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+micron-sized,+monodisperse+polymer+particles+of+disc-like+and+polyhedral+shapes+by+seeded+dispersion+polymerization.">Synthesis of micron-sized, monodisperse polymer particles of disc-like and polyhedral shapes by seeded dispersion polymerization.</a> Colloid Polym Sci. 283 (7), 793-798 (2005).</li><li>Fujibayashi, T., Okubo, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+Thermodynamic+Stability+of+Micron-Sized,+Monodisperse+Composite+Polymer+Particles+of+Disc-like+Shapes+by+Seeded+Dispersion+Polymerization.">Preparation and Thermodynamic Stability of Micron-Sized, Monodisperse Composite Polymer Particles of Disc-like Shapes by Seeded Dispersion Polymerization.</a> Langmuir. 23 (15), 7958-7962 (2007).</li><li>Okubo, M., Fujibayashi, T., Yamada, M., Minami, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micron-sized,+monodisperse,+snowman/confetti-shaped+polymer+particles+by+seeded+dispersion+polymerization.">Micron-sized, monodisperse, snowman/confetti-shaped polymer particles by seeded dispersion polymerization.</a> Colloid Polym Sci. 283 (9), 1041-1045 (2005).</li><li>Xu, S., 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=Generation+of+Monodisperse+Particles+by+Using+Microfluidics:+Control+over+Size,+Shape,+and+Composition.">Generation of Monodisperse Particles by Using Microfluidics: Control over Size, Shape, and Composition.</a> Angew Chem Int Ed. 44 (5), 724-728 (2005).</li><li>Serra, C. A., Chang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic-Assisted+Synthesis+of+Polymer+Particles.">Microfluidic-Assisted Synthesis of Polymer Particles.</a> Chem Eng Tech. 31 (8), 1099-1115 (2008).</li><li>Higuchi, T., Yabu, H., Shimomura, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simple+preparation+of+hemispherical+polystyrene+particles.">Simple preparation of hemispherical polystyrene particles.</a> Colloids Surf A. 284, 250-253 (2006).</li><li>Sun, Z. Q., 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=Nonspherical+Colloidal+Crystals+Fabricated+by+the+Thermal+Pressing+of+Colloidal+Crystal+Chips.">Nonspherical Colloidal Crystals Fabricated by the Thermal Pressing of Colloidal Crystal Chips.</a> Langmuir. 21 (20), 8987-8991 (2005).</li><li>Deng, Y., 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=A+novel+approach+to+the+construction+of+3-D+ordered+macrostructures+with+polyhedral+particles.">A novel approach to the construction of 3-D ordered macrostructures with polyhedral particles.</a> J Mater Chem. 18 (4), 408-415 (2008).</li><li>Hyuk Im, S., Jeong, U., Xia, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymer+hollow+particles+with+controllable+holes+in+their+surfaces.">Polymer hollow particles with controllable holes in their surfaces.</a> Nat Mater. 4 (9), 671-675 (2005).</li><li>Saito, N., Kagari, Y., Okubo, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+Colloidal+Stabilizer+on+the+Shape+of+Polystyrene/Poly(methyl+methacrylate)+Composite+Particles+Prepared+in+Aqueous+Medium+by+the+Solvent+Evaporation+Method.">Effect of Colloidal Stabilizer on the Shape of Polystyrene/Poly(methyl methacrylate) Composite Particles Prepared in Aqueous Medium by the Solvent Evaporation Method.</a> Langmuir. 22 (22), 9397-9402 (2006).</li><li>Cai, P. -. j., Tang, Y. -. j., Wang, Y. -. t., Cao, Y. -. j. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+polystyrene+hollow+spheres+in+W/O/W+multiple+emulsions.">Fabrication of polystyrene hollow spheres in W/O/W multiple emulsions.</a> Mater Chem Phys. 124 (1), 10-12 (2010).</li><li>Liang, S. -. S., Chen, S. -. L., Chen, S. -. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diverse+macroporous+spheres+synthesized+by+multiple+emulsion+polymerization+for+protein+analyses.">Diverse macroporous spheres synthesized by multiple emulsion polymerization for protein analyses.</a> Chem Commun. 47 (29), 8385-8387 (2011).</li><li>Kondo, Y., Yoshino, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hybrid+fluorocarbon/hydrocarbon+surfactants.">Hybrid fluorocarbon/hydrocarbon surfactants.</a> Curr Opin Colloid Interface Sci. 10 (3-4), 88-93 (2005).</li><li>Takahashi, Y., Kondo, Y., Schmidt, J., Talmon, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-Assembly+of+a+Fluorocarbon-Hydrocarbon+Hybrid+Surfactant:+Dependence+of+Morphology+on+Surfactant+Concentration+and+Time.">Self-Assembly of a Fluorocarbon-Hydrocarbon Hybrid Surfactant: Dependence of Morphology on Surfactant Concentration and Time.</a> J Phys Chem B. 114 (42), 13319-13325 (2010).</li><li>Takahashi, Y., Nasu, Y., Aramaki, K., Kondo, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unusual+viscoelastic+behavior+of+aqueous+solutions+of+fluorocarbon-hydrocarbon+hybrid+surfactant+and+its+morphological+transformations.">Unusual viscoelastic behavior of aqueous solutions of fluorocarbon-hydrocarbon hybrid surfactant and its morphological transformations.</a> J Fluor Chem. 145, 141-147 (2013).</li><li>Yoshino, N., 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=Syntheses+of+Hybrid+Anionic+Surfactants+Containing+Fluorocarbon+and+Hydrocarbon+Chains.">Syntheses of Hybrid Anionic Surfactants Containing Fluorocarbon and Hydrocarbon Chains.</a> Langmuir. 11 (2), 466-469 (1995).</li><li>Zarzar, L. D., 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=Dynamically+reconfigurable+complex+emulsions+via+tunable+interfacial+tensions.">Dynamically reconfigurable complex emulsions via tunable interfacial tensions.</a> Nature. 518 (7540), 520-524 (2015).</li></ol>

Non abbiamo nulla di divulgare.

Le emulsioni contenenti goccioline di Janus di stirene e PFO sono state ottenute sopra 10 wt % della frazione peso di concentrazione acquosa di SDS e qualsiasi frazione di peso di stirene e PFO. Quando le varie frazioni di peso delle emulsioni contenenti le goccioline di Janus sono state polimerizzate per 30 min, le particelle di polistirene Cave sono ottenibili per ogni composizione. Questi risultati indicano che il protocollo ha dimostrato qui è semplice. Inoltre, il diametro, dimensione di foro e foro volume delle particelle polistirolo vuote può essere controllati con il tempo di polimerizzazione nel metodo descritto qui.
Suggeriamo il seguente meccanismo per la realizzazione della Cave particelle di polistirene. Gocce d'olio di Janus costituito di stirene e PFO formata in emulsioni O/W contenenti miscele di soluzione acquosa SDS, stirene e PFO a 80 ° C. Goccioline PFO si trovano sulla superficie delle goccioline di stirene. Poiché KPS, un iniziatore di polimerizzazione, è solubile nella fase acquosa, la polimerizzazione progredirà all'interfaccia della soluzione SDS stirene/acquosa. Stirene nelle emulsioni ternarie era polimerizzato a polistirolo a 80 ° C, mentre la PFO, non avendo nessun gruppi polimerizzabili, è rimasta in emulsioni a quella temperatura. Dopo la polimerizzazione è stata terminata, un foro sulla particella polistirolo fu creato dalla rimozione del PFO. Di conseguenza, le particelle di polistirene cava Coppa-tipo avendo un foro sulla superficie erano fabbricati Chiunquesi frazione di peso di stirene e PFO e tutti i tempi di polimerizzazione.
Aggiungendo una piccola quantità di toluene per le particelle di polistirene Cave fabbricate tramite polimerizzazione radicale per 90 min porta i fori sulle particelle di polistirolo vuote di tenuta. Questo fenomeno è coerente con quello riportato da Hyuk et al.9. Il metodo lipooligosaccharide può contenere un materiale acquoso nelle particelle.
In questo articolo, abbiamo dimostrato un metodo di fabbricazione delle particelle di polimero hollow utilizzando le goccioline di olio di Janus costituito di stirene e PFO, che sono mutuamente immiscibili. Il metodo di preparazione di particelle di polimero non-sferico è già stato studiato a causa del loro potenziale uso in varie applicazioni. Questa strategia utilizzando goccioline di olio di idrocarburi e fluorocarbon per Janus si applica alla fabbricazione di particelle di polimero non sferica da vari tipi di monomero e drug delivery system.

Mentre le particelle sferiche polimero sono stati ampiamente utilizzate in diverse applicazioni industriali, è ben noto che le particelle fossetta, emisferi, dischi ed Elissoidi, sono state preparate da seminato polimerizzazioni1,2, 3, foto-polimerizzazione delle goccioline di monomero non sferica utilizzando microreattore con geometrie specifiche4,5, auto-organizzazione utilizzando riprecipitazione di polimeri6e deformazione dei polimeri sferici le particelle da esterno meccanico forza7,8. In particolare, particelle di polimero cava con micrometro-dimensione sono state fabbricate da evaporazione di un buon solvente da particelle di polimero sferica gonfiata dal solvente9,10 e polimerizzazione utilizzando emulsioni multiple 11 , 12.
In questo lavoro, ci concentriamo sull'uso del reciproco immiscibilità di idrocarburi e fluorocarbon oli nella fabbricazione delle particelle di polimero. Tensioattivi di ibridi hanno una catena di idrocarburi e una catena di fluorocarburo nella molecola. Precedentemente, abbiamo segnalato le proprietà uniche dei tensioattivi ibrido che non si osservano in tensioattivi convenzionali13,14,15. Inoltre abbiamo studiato emulsioni utilizzando olio di idrocarburi, olio fluorocarburo e soluzione acquosa tensioattivo, che sono mutuamente immiscibili16. Tuttavia, ci sono pochissimi studi delle emulsioni17. Questi studi hanno descritto la morfologia delle goccioline di olio composto da olio di idrocarburi e olio di fluorocarbonio in soluzioni acquose tensioattivo.
Qui, indichiamo un protocollo dettagliato della fabbricazione delle particelle di polimero cava tramite polimerizzazione radicale usando gocce d'olio nelle emulsioni consistenti di idrocarburo, olio fluorocarburo e acquosa sodio dodecilsolfato (SDS) soluzioni. Suggeriamo una nuova strategia, che è diversa dai metodi convenzionali, per la preparazione di particelle di polimero non-sferico. Questo metodo può semplicemente fabbricare le particelle di polimero cava in breve tempo. Inoltre, il protocollo della preparazione di microcapsule attraverso le particelle di polimero hollow è indicato.

<table>
	<tbody>
		<tr>
			<td>Material</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium dodecylsulfate, 95.0%</td>
			<td>Wako Pure Chemical Industries, Ltd.</td>
			<td>192-08672</td>
			<td></td>
		</tr>
		<tr>
			<td>Styrene, 99.0%</td>
			<td>Tokyo Chemical Industry Co. Ltd.</td>
			<td>S0095</td>
			<td></td>
		</tr>
		<tr>
			<td>Perfluorooctane, 99%</td>
			<td>Fluorochem Ltd.</td>
			<td>8706</td>
			<td></td>
		</tr>
		<tr>
			<td>Coumarin 102, 97.0%</td>
			<td>Tokyo Chemical Industry Co. Ltd.</td>
			<td>C2267</td>
			<td></td>
		</tr>
		<tr>
			<td>Calcein</td>
			<td>Dojindo Molecular Technologies, Inc.</td>
			<td>C001</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium peroxodisulfate, 98.0%</td>
			<td>Kanto Chemical Co., Inc.</td>
			<td>32375-30</td>
			<td></td>
		</tr>
		<tr>
			<td>Pyrene, 97.0%</td>
			<td>Wako Pure Chemical Industries, Ltd.</td>
			<td>167-05302</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol, 99.5%</td>
			<td>Kanto Chemical Co., Inc.</td>
			<td>14033-00</td>
			<td></td>
		</tr>
		<tr>
			<td>Toluene, 99.5%</td>
			<td>Kanto Chemical Co., Inc.</td>
			<td>40180-00</td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Scanning Electron Microscope</td>
			<td>Hitachi High-Technologies Corporation</td>
			<td>S-4800</td>
			<td></td>
		</tr>
		<tr>
			<td>Scanning Transmission Electron Microscope</td>
			<td>Hitachi High-Technologies Corporation</td>
			<td>S-4800</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultrasonic cleaner</td>
			<td>Branson Ultrasonics, Emerson Japan, Ltd.</td>
			<td>Model 3510</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>AS ONE Corporation</td>
			<td>CN-1050</td>
			<td></td>
		</tr>
	</tbody>
</table>

preparation of hollow polystyrene particles and microcapsules by radical polymerization of janus droplets consisting of hydrocarbon and fluorocarbon oils

In questo articolo, abbiamo dimostrato un metodo per produrre particelle vuote e microcapsule usando le goccioline di olio composto da olio di idrocarburi (stirene) e fluorocarburi (perfluoro -n-ottano, PFO) in acquoso tensioattivo (sodio dodecilsolfato, Soluzioni di SDS). Poiché fluorocarburo oli sono immiscibili con oli di idrocarburi, i due oli sono separati. Emulsioni sono preparati da agitazione stirene/PFO/acquosa miscele di soluzione SDS a 80 ° C. Il tipo delle emulsioni e la morfologia delle goccioline nelle emulsioni sono osservati da microscopio ottico e microscopio a fluorescenza confocale. È trovato che le goccioline di olio con morfologie di Janus-tipo costituito di stirene reciprocamente immiscibili e PFO si formano in soluzione acquosa di SDS. Particelle di polistirene sono fabbricate tramite polimerizzazione radicale di mischie ternarie di stirene/PFO/acquoso soluzione di SDS a 80 ° C. Le morfologie del polistirolo sono confermate da microscopia elettronica a scansione e scansione osservazioni di microscopia elettronica di trasmissione. Queste osservazioni mostrano la preparazione di particelle di polistirene Cave con un unico foro sulla superficie. A nostra conoscenza, questo metodo è una strategia novella utilizzando l'immiscibilità di oli idrocarburi e fluorocarbon. Le particelle di Cave possono essere applicate anche alla preparazione delle microcapsule.

Luce e osservazioni di microscopia di fluorescenza confocale di scansione sono stati effettuati per determinare la morfologia e la composizione delle goccioline nelle emulsioni costituito di stirene, PFO e soluzione di SDS acquosa 5 mM (Figura 1). Analisi in microscopia elettronica (SEM) e analisi osservazioni di microscopia elettronica (STEM) trasmissione ha mostrato la formazione di particelle vuote e microcapsule (Figura 2).
Il DIC e immagini di microscopia di fluorescenza confocale di emulsioni costituite da miscele ternarie di stirene/PFO/acquoso soluzione SDS indicano che la fase continua è la soluzione acquosa di SDS, perché fluorescenza verde corrispondente alla calceina è stata osservata in la fase continua, e di conseguenza, si formano emulsioni olio-in-acqua tipo (Figura 1a e 1b). Queste immagini mostrano anche che le goccioline di olio consistono di stirene e PFO, che sono mutuamente immiscibili. Il DIC e immagini di microscopia di fluorescenza confocale di emulsioni contenenti cumarina 102 rivelano che una gocciolina PFO si trova all'interfaccia tra acqua e una goccia di stirene. Le miscele ternarie di stirene, PFO e soluzione acquosa di SDS alle emulsioni di forma 5 mM contenenti Janus olio goccioline, che consistono di stirene e PFO.
Le immagini di SEM e staminali delle particelle di polimero fabbricate dalla polimerizzazione radicale delle emulsioni di soluzione acquosa di SDS stirene/PFO/5mm mostrano la preparazione di particelle di polistirene non sferica Cave con un foro sulla superficie (Figura 2a e 2b). il tasso di formazione, il diametro e la dimensione del foro della Cave particelle di polistirene vengono valutati osservando 200 particelle attraverso SEM e staminali. Il diametro medio stimato dalle osservazioni di SEM è 1.3 µm. La dimensione è coerenza con il diametro delle particelle di polimero stimato da misure di dispersione della luce dinamica. Il tasso di formazione è circa il 100%. La media di dimensione del foro e il volume del foro nelle particelle vuote sono 0,8 µm ± 0,4 e 0,9 ± 0,4 µm3, rispettivamente. Di conseguenza, le particelle di polistirene Cave munito di un foro di 0,8 µm furono fabbricate tramite polimerizzazione radicale di goccioline di Janus contenenti stirene nelle emulsioni.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56922/56922fig1.jpg"> Figura 1. Morfologie delle goccioline nelle emulsioni consistenti di soluzione acquosa di SDS stirene, PFO e 5 mM. (a) contrasto differenziale di interferenza (DIC) e (b) immagini di microscopia di fluorescenza confocale delle emulsioni contenenti calceina fluorescente acquosa. (c) DIC e (d) immagini di microscopia confocal di fluorescenza delle emulsioni contenenti olio solubile fluorescente cumarina 102. <a href="//cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56922/56922fig1large.jpg" target="_blank">Clicca qui per visualizzare una versione più grande di questa figura.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56922/56922fig2.jpg"> Figura 2. Morfologie di Cave particelle di polistirene e microcapsule fabbricati con emulsioni consistenti di soluzione acquosa di SDS stirene, PFO e 5 mM. (a) immagini di staminali SEM e (b) di particelle di polistirene hollow. (c) SEM e (d) immagini di staminali di microcapsule. <a href="//cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56922/56922fig2large.jpg" target="_blank">Clicca qui per visualizzare una versione più grande di questa figura.</a>

Watch this Scientific Journal Video about Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils at J

Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils

Preparazione di Cave particelle di polistirene e microcapsule tramite polimerizzazione radicale di goccioline di Janus composto da idrocarburi e oli Fluorocarbon

Un protocollo per la fabbricazione di particelle di polimero hollow e microcapsule di polimerizzazione radicalica utilizzando emulsioni consistenti di stirene, perfluoro -n-ottano e acquosa SDS (sodio dodecilsolfato) soluzione è presentata.

In this article, we have demonstrated a method for producing hollow particles and microcapsules using oil droplets consisting of hydrocarbon oil (styrene) ...

preparation-hollow-polystyrene-particles-microcapsules-radical

Nanyang Technological University

Research

JoVE Journal

Chemistry

9.9K Views.  Tokyo University of Science. Un protocollo per la fabbricazione di particelle di polimero hollow e microcapsule di polimerizzazione radicalica utilizzando emulsioni consistenti di stirene, perfluoro -n-ottano e acquosa SDS (sodio dodecilsolfato) soluzione è presentata.

Video: Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils

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.

Origami Ispirato auto-assemblaggio di particelle Fantasia e riconfigurabile

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

Ricerca

Chimica

Exploring the Radical Nature of a Carbon Surface by Electron Paramagnetic Resonance and a Calibrated Gas Flow

While the first Electron Paramagnetic Resonance (EPR) studies regarding the effects of oxidation on the structure and stability of carbon radicals date back to the early 1980s the focus of these early papers primarily characterized the changes to the structures under extremely harsh conditions (pH or temperature)1-3. It is also known that paramagnetic molecular oxygen undergoes a Heisenberg spin exchange interaction with stable radicals that extremely broadens the EPR signal4-6. Recently, we reported interesting results where this interaction of molecular oxygen with a certain part of the existing stable radical structure can be reversibly affected simply by flowing a diamagnetic gas through the carbon samples at STP7. As flows of He, CO2, and N2 had a similar effect these interactions occur at the surface area of the macropore system.
This manuscript highlights the experimental techniques, work-up, and analysis towards affecting the existing stable radical nature in the carbon structures. It is hoped that it will help towards further development and understanding of these interactions in the community at large.

Stable radicals that are present in carbon substrates interact with paramagnetic oxygen through a Heisenberg spin exchange. This interaction can be significantly reduced under STP conditions by flowing a diamagnetic gas over the carbon system. This manuscript describes a simple method to characterize the nature of those radicals.

Esplorare la natura radicale di una superficie Carbonio Electron risonanza paramagnetica e calibrato di flusso del gas

While the first Electron Paramagnetic Resonance (EPR) studies regarding the effects of oxidation on the structure and stability of carbon radicals date ...

Facile and Efficient Preparation of Tri-component Fluorescent Glycopolymers via RAFT-controlled Polymerization

Synthetic glycopolymers are instrumental and versatile tools used in various biochemical and biomedical research fields. An example of a facile and efficient synthesis of well-controlled fluorescent statistical glycopolymers using reversible addition-fragmentation chain-transfer (RAFT)-based polymerization is demonstrated. The synthesis starts with the preparation of &#946;-galactose-containing glycomonomer 2-lactobionamidoethyl methacrylamide obtained by reaction of lactobionolactone and N-(2-aminoethyl) methacrylamide (AEMA). 2-Gluconamidoethyl methacrylamide (GAEMA) is used as a structural analog lacking a terminal &#946;-galactoside. The following RAFT-mediated copolymerization reaction involves three different monomers: N-(2-hydroxyethyl) acrylamide as spacer, AEMA as target for further fluorescence labeling, and the glycomonomers. Tolerant of aqueous systems, the RAFT agent used in the reaction is (4-cyanopentanoic acid)-4-dithiobenzoate. Low dispersities (&#8804;1.32), predictable copolymer compositions, and high reproducibility of the polymerizations were observed among the products. Fluorescent polymers are obtained by modifying the glycopolymers with carboxyfluorescein succinimidyl ester targeting the primary amine functional groups on AEMA. Lectin-binding specificities of the resulting glycopolymers are verified by testing with corresponding agarose beads coated with specific glycoepitope recognizing lectins. Because of the ease of the synthesis, the tight control of the product compositions and the good reproducibility of the reaction, this protocol can be translated towards preparation of other RAFT-based glycopolymers with specific structures and compositions, as desired.

An efficient, three-step synthesis of RAFT-based fluorescent glycopolymers, consisting of glycomonomer preparation, copolymerization, and post-modification, is demonstrated. This protocol can be used to prepare RAFT-based statistical glycopolymers with desired structures.

Preparazione Facile ed efficiente di Glycopolymers fluorescenti Tri-componenti tramite polimerizzazione RAFT controllata

Synthetic glycopolymers are instrumental and versatile tools used in various biochemical and biomedical research fields. An example of a facile and ...

Using Polystyrene-block-poly(acrylic acid)-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are encapsulated in polystyrene-block-poly(acrylic acid) (PSPAA) shells and then used as monomers for their self-assembly. Spherical PSPAA micelles upon acid treatment are known to assemble into cylindrical micelles. Exploiting this tendency, the core-shell nanoparticles are induced to aggregate, coalesce, and then transform into long chains. When more than one type of nanoparticles are used, random and block &#8220;copolymers&#8221; of nanoparticles can be obtained. Detailed procedures are reported for the PSPAA encapsulation of nanoparticles, homo- and co-polymerization of the core-shell nanoparticles, separation and purification of the resulting nanoparticle chains. Transformations of single-line chains into double- and triple-line chains are also presented. The synergy between the polymer shell and the embedded nanoparticles leads to an unusual chain-growth polymerization mode, giving long nanoparticle chains that are distinct from the products of the traditional step-growth aggregation process.

Using Polystyrene-block-polyacrylic acid-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We report protocols for &#8220;polymerizing&#8221; various types of polymer-encapsulated metal nanoparticles into long chains of &#8220;homo-&#8220; and &#8220;co-polymers&#8221;.

Utilizzando Polystyrene-<em&gt; Blocco</em&gt; -poly (Acido acrilico) Rivestiti metallo Nanoparticelle come monomeri per loro omo- e co-polimerizzazione

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are ...

Facile Preparation of Internally Self-assembled Lipid Particles Stabilized by Carbon Nanotubes

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled (functionalized) CNTs are used as stabilizers to produce Pickering type oil-in-water (O/W) emulsions. Lipids namely, Dimodan U and Phytantriol are used as emulsifiers, which in excess water self-assemble into the bicontinuous cubic Pn3m phase. This highly viscous phase is fragmented into smaller particles using a probe ultrasonicator in presence of conventional surfactant stabilizers or CNTs as done here. Initially, the CNTs (powder form) are dispersed in water followed by further ultrasonication with the molten lipid to form the final emulsion. During this process the CNTs get coated with lipid molecules, which in turn are presumed to surround the lipid droplets to form a particulate emulsion that is stable for months. The average size of CNT-stabilized nanostructured lipid particles is in the submicron range, which compares well with the particles stabilized using conventional surfactants. Small angle X-ray scattering data confirms the retention of the original Pn3m cubic phase in the CNT-stabilized lipid dispersions as compared to the pure lipid phase (bulk state). Blue shift and lowering of the intensities in characteristic G and G&#39; bands of CNTs observed in Raman spectroscopy characterize the interaction between CNT surface and lipid molecules. These results suggest that the interactions between the CNTs and lipids are responsible for their mutual stabilization in aqueous solutions. As the concentrations of CNTs employed for stabilization are very low and lipid molecules are able to functionalize the CNTs, the toxicity of CNTs is expected to be insignificant while their biocompatibility is greatly enhanced. Hence the present approach finds a great potential in various biomedical applications, for instance, for developing hybrid nanocarrier systems for the delivery of multiple functional molecules as in combination therapy or polytherapy.

We report on a smart application of carbon nanotubes for kinetic stabilization of lipid particles that contain self-assembled nanostructures in their cores. The preparation of lipid particles requires rather low concentrations of carbon nanotubes permitting their use in biomedical applications such as drug delivery.

Preparazione facile di Internamente auto-assemblato Lipid particelle stabilizzati da nanotubi di carbonio

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled ...

Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst

A standardized technique for atom transfer radical polymerization of vinyl monomers using perylene as a visible-light photocatalyst is presented. The procedure is performed under an inert atmosphere using air- and water-exclusion techniques. The outcome of the polymerization is affected by the ratios of monomer, initiator, and catalyst used as well as the reaction concentration, solvent, and nature of the light source. Temporal control over the polymerization can be exercised by turning the visible light source off and on. Low dispersities of the resultant polymers as well as the ability to chain-extend to form block copolymers suggest control over the polymerization, while chain end-group analysis provides evidence supporting an atom-transfer radical polymerization mechanism.

A method for the atom transfer radical polymerization of functionalized vinyl monomers using perylene as a visible-light photocatalyst is described.

Atom Transfer Radical polimerizzazione di monomeri funzionalizzati vinile Utilizzo Perilene da fotocatalizzatore luce visibile

A standardized technique for atom transfer radical polymerization of vinyl monomers using perylene as a visible-light photocatalyst is presented. The ...

On-line Analysis of Nitrogen Containing Compounds in Complex Hydrocarbon Matrixes

The shift to heavy crude oils and the use of alternative fossil resources such as shale oil are a challenge for the petrochemical industry. The composition of heavy crude oils and shale oils varies substantially depending on the origin of the mixture. In particular they contain an increased amount of nitrogen containing compounds compared to the conventionally used sweet crude oils. As nitrogen compounds have an influence on the operation of thermal processes occurring in coker units and steam crackers, and as some species are considered as environmentally hazardous, a detailed analysis of the reactions involving nitrogen containing compounds under pyrolysis conditions provides valuable information. Therefore a novel method has been developed and validated with a feedstock containing a high nitrogen content, i.e., a shale oil. First, the feed was characterized offline by comprehensive two-dimensional gas chromatography (GC &#215; GC) coupled with a nitrogen chemiluminescence detector (NCD). In a second step the on-line analysis method was developed and tested on a steam cracking pilot plant by feeding pyridine dissolved in heptane. The former being a representative compound for one of the most abundant classes of compounds present in shale oil. The composition of the reactor effluent was determined via an in-house developed automated sampling system followed by immediate injection of the sample on a GC &#215; GC coupled with a time-of-flight mass spectrometer (TOF-MS), flame ionization detector (FID) and NCD. A novel method for quantitative analysis of nitrogen containing compounds using NCD and 2-chloropyridine as an internal standard has been developed and demonstrated.

A method combining comprehensive two-dimensional gas chromatography with nitrogen chemiluminescence detection has been developed and applied to on-line analysis of nitrogen containing compounds in a complex hydrocarbon matrix.

Analisi on-line dei composti contenenti azoto in matrici idrocarburi complessi

The shift to heavy crude oils and the use of alternative fossil resources such as shale oil are a challenge for the petrochemical industry. The ...

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by &#960;-&#960; Stacking Interactions

In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE). Characterization of the copolymer revealed a narrow molecular distribution (PDI &#60; 1.03) and confirmed the degree of polymerization of mPEG122-b-(PheGE)15. The critical micelle concentration of the copolymer was evaluated using an established fluorescence method with the aggregation behavior evaluated by dynamic light scattering and transmission electronic microscopy. The potential of the copolymer for use in drug delivery applications was evaluated in a preliminary manner including in vitro biocompatibility, loading and release of the hydrophobic anti-cancer drug doxorubicin (DOX). A stable micelle formulation of DOX was prepared with drug loading levels up to 14% (wt%), drug loading efficiencies &#62; 60% (w/w) and sustained release of drug over 4 days under physiologically relevant conditions (acidic and neutral pH, presence of albumin). The high drug loading level and sustained release is attributed to stabilizing &#960;-&#960; interactions between DOX and the core-forming block of the micelles.

The key steps of living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE) are described. The resulting block copolymer micelles (BCMs) were loaded with doxorubicin 14% (wt%) and sustained release of drug over 4 days under physiologically relevant conditions was obtained.

Anionico polimerizzazione di un copolimero Amphiphilic per la preparazione di copolimero a blocchi micelle stabilizzata da π-¸ Interazioni Stacking

In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl ...

A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic nature of the monomer is conserved. The resulting polymer, polynorbornene, has a very high glass transition temperature, Tg, and interesting optical and electrical properties. However, the polymerization of functional norbornenes by this mechanism is complicated by the fact that the endo substituted norbornene monomer has, in general, a very low reactivity. Furthermore, the separation of the endo substituted monomer from the exo monomer is a tedious task. Here, we present a simple protocol for the polymerization of substituted norbornenes (endo:exo ca. 80:20) bearing either a carboxylic acid or a pendant double bond. The process does not require that both isomers be separated, and proceeds with low catalyst loadings (0.01 to 0.02 mol%). The polymer bearing pendant double bonds can be further transformed in high yield, to afford a polymer bearing pendant epoxy groups. These simple procedures can be applied to prepare polynorbornenes with a variety of functional groups, such as esters, alcohols, imides, double bonds, carboxylic acids, bromo-alkyls, aldehydes and anhydrides.

We describe the catalytic insertion polymerization of 5-norbornene-2-carboxylic acid and 5-vinyl-2-norbornene to form functional polymers with a very high glass transition temperature.

Un protocollo semplice ed efficiente per l&#39;inserimento catalitica polimerizzazione di norborneni funzionali

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic ...

Determination of Carbonyl Functional Groups in Bio-oils by Potentiometric Titration: The Faix Method

Carbonyl compounds present in bio-oils are known to be responsible for bio-oil property changes upon storage and during upgrading. Specifically, carbonyls cause an increase in viscosity (often referred to as &#39;aging&#39;) during storage of bio-oils. As such, carbonyl content has previously been used as a method of tracking bio-oil aging and condensation reactions with less variability than viscosity measurements. Additionally, carbonyls are also responsible for coke formation in bio-oil upgrading processes. Given the importance of carbonyls in bio-oils, accurate analytical methods for their quantification are very important for the bio-oil community. Potentiometric titration methods based on carbonyl oximation have long been used for the determination of carbonyl content in pyrolysis bio-oils. Here, we present a modification of the traditional carbonyl oximation procedures that results in less reaction time, smaller sample size, higher precision, and more accurate carbonyl determinations. While traditional carbonyl oximation methods occur at room temperature, the Faix method presented here occurs at an elevated temperature of 80 &#176;C.

Here we present a potentiometric titration technique for accurately quantifying carbonyl compounds in pyrolysis bio-oils.

Determinazione del carbonile gruppi funzionali in Bio-oli da potenziometrica Titolazione: Il Metodo Faix

Carbonyl compounds present in bio-oils are known to be responsible for bio-oil property changes upon storage and during upgrading. Specifically, carbonyls ...