This work was supported as part of the Advanced Materials for Energy-Water Systems (AMEWS) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. We gratefully acknowledge helpful discussions with Mark Stoykovich and Paul Nealey.

1. Fabrication of the transfer tool and drain chamber system
<ol>
	<li>Attached (Supplementary Files 1, 2) is the engineering drawing for the drain chamber assembly consisting of two parts: top and bottom. Model this device according to the specifications of the desired system (e.g., the outer diameter of the receiving substrate) and export as an STL file for 3D printing.</li>
	<li>For the top part, utilize a filament printer of choice and print in the lowest resolution possible, including scaffolding wherever necessary. Adhere to the recommended parameters of the printer. It is also recommended that the top part be printed using poly(lactic acid) (PLA) to minimize material shedding.</li>
	<li>For the bottom part, use an inkjet resin printer or filament printer with a build height as fine as 20 &#181;m. 
	NOTE: PLA is a suitable material which minimizes material shedding.</li>
	<li>Scrub and clean both parts with deionized water, ensuring the removal of any potential shedding material from the printing process. Sonication in deionized water is also recommended. Test the threading on the two parts to ensure a good fit.</li>
	<li>Complete the drain chamber with a size 117 neoprene O-ring and tubing of the parameters specified in the supporting documents (Supplementary Files 1, 2). A schematic of the entire drain chamber assembly is shown in Figure 1.</li>
	<li>Print the transfer tool using any filament printer at medium to fine resolution. There are two parts: clamp and loading arm. 
	NOTE: It is highly recommended that the transfer tool be printed using poly(lactic acid) (PLA), as other plastics can be poorly wetted and cause the wafer to become wet unexpectedly.</li>
	<li>Complete the clamp with a size 10 screw and then attach the clamp onto a laboratory jack.</li>
</ol>
2. Initial mechanized deposition and membrane lift-off from donor substrate
<ol>
	<li>Place a bare 25 mm-diameter AAO disc (or any arbitrary porous receiver substrate of choice) onto the bottom part of the drain chamber. Then, place the neoprene O-ring on top of the AAO disc and screw on the top part of the drain chamber.</li>
	<li>Rinse and/or sonicate the setup various times with deionized (DI) water. This helps to remove any dust and/or any remaining particulates from 3D printing.</li>
	<li>Place the piece of Si wafer with the transferable polymer stack (donor wafer) onto the lip of the transfer tool loading arm.</li>
	<li>Fill the drain chamber with 25 mL of DI water.</li>
	<li>Lower the laboratory jack so that the tool is dipped slowly into the entrance ramp of the drain chamber and that the donor silicon substrate is slowly submerged. Ensure that the wafer is submerged sufficiently for the membrane to completely delaminate and lift-off from the underlying donor substrate. 
	NOTE: Using a piece of Si wafer with no dust contamination will ensure easy separation from the donor substrate.</li>
	<li>Slowly raise the transfer tool out of the water and move it out of the way, making sure not to disturb the floating membrane.</li>
	<li>Coax the membrane into the opening of the chamber with tweezers. Placing the tweezer in water in front of membrane will guide it due to surface tension. Touching the floating membrane itself is not necessary and should be avoided.</li>
</ol>
3. Meniscus-guided transfer to receiver substrate with the drain chamber system
<ol>
	<li>Connect tubing to the outlet of the bottom part of the drain chamber. Attach this tubing to a 20 mL Luer-lock syringe.</li>
	<li>Obtain a syringe pump with withdrawing functionality. Place the syringe onto the pump and withdraw water at a rate of 1-2.5 mL/min until all the water has been drained out.</li>
	<li>After 10 min, the water should be completely removed from the drain chamber. If there is still any residual water within the chamber, reconnect the syringe and tubing and continue to withdraw any residual water.</li>
	<li>After complete drainage of the water, the membrane will now be placed at the center of the receiver substrate. Disconnect the drain chamber from the syringe pump and disassemble the drain chamber to remove the receiver substrate containing the membrane. 
	NOTE: The total process including set-up takes ~15 min. Reducing the working volume of water and increasing the drain rate can shorten this process.</li>
	<li>Allow the sample to dry completely at room temperature before further use in any application.</li>
</ol>

<ol>
	<li>Shah, A., Torres, P., Tscharner, R., Wyrsch, N., Keppner, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photovoltaic+technology:+the+case+for+thin-film+solar+cells.">Photovoltaic technology: the case for thin-film solar cells.</a> Science. 285 (5428), 692-698 (1999).</li><li>Kim, T. 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=Full-colour+quantum+dot+displays+fabricated+by+transfer+printing.">Full-colour quantum dot displays fabricated by transfer printing.</a> Nat. Photon. 5 (3), 176 (2011).</li><li>Nomura, 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=Room-temperature+fabrication+of+transparent+flexible+thin-film+transistors+using+amorphous+oxide+semiconductors.">Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors.</a> Nature. 432 (7016), 488 (2004).</li><li>Pirkle, A., 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=The+effect+of+chemical+residues+on+the+physical+and+electrical+properties+of+chemical+vapor+deposited+graphene+transferred+to+SiO2.">The effect of chemical residues on the physical and electrical properties of chemical vapor deposited graphene transferred to SiO2.</a> Applied Physics Letters. 99 (12), 122108-122110 (2011).</li><li>Chae, S. J., 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=Synthesis+of+large-area+graphene+layers+on+poly-nickel+substrate+by+chemical+vapor+deposition:+wrinkle+formation.">Synthesis of large-area graphene layers on poly-nickel substrate by chemical vapor deposition: wrinkle formation.</a> Advanced Materials. 21 (22), 2328-2333 (2009).</li><li>Zhu, W., 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=Structure+and+electronic+transport+in+graphene+wrinkles.">Structure and electronic transport in graphene wrinkles.</a> Nano Letters. 12 (7), 3431-3436 (2012).</li><li>Paronyan, T. M., Pigos, E. M., Chen, G., Harutyunyan, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+of+ripples+in+graphene+as+a+result+of+interfacial+instabilities.">Formation of ripples in graphene as a result of interfacial instabilities.</a> ACS Nano. 5 (12), 9619-9627 (2011).</li><li>Stadermann, M., 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=Fabrication+of+large-area+free-standing+ultrathin+polymer+films.">Fabrication of large-area free-standing ultrathin polymer films.</a> Journal of Visualized Experiments : JoVE. (100), e52832 (2015).</li><li>Zhou, 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=Fabrication+of+Nanoporous+Alumina+Ultrafiltration+Membrane+with+Tunable+Pore+Size+Using+Block+Copolymer+Templates.">Fabrication of Nanoporous Alumina Ultrafiltration Membrane with Tunable Pore Size Using Block Copolymer Templates.</a> Advanced Functional Materials. 27 (34), 1701756 (2017).</li><li>Meitl, M. A., 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=Transfer+printing+by+kinetic+control+of+adhesion+to+an+elastomeric+stamp.">Transfer printing by kinetic control of adhesion to an elastomeric stamp.</a> Nature Materials. 5 (1), 33 (2006).</li><li>Suk, J. W., 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=Transfer+of+CVD-grown+monolayer+graphene+onto+arbitrary+substrates.">Transfer of CVD-grown monolayer graphene onto arbitrary substrates.</a> ACS Nano. 5 (9), 6916-6924 (2011).</li><li>Chen, Y., Gong, X. L., Gai, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progress+and+Challenges+in+Transfer+of+Large-Area+Graphene+Films.">Progress and Challenges in Transfer of Large-Area Graphene Films.</a> Advanced Science. 3 (8), 1500343 (2016).</li></ol>

The authors have nothing to disclose.

While many of the steps listed in this protocol are crucial for the success of the thin film transfer, the nature of the custom-designed 3D printed drain chamber allows for broad flexibility, according to the user's specific requirements. For example, if the receiver substrate has a larger diameter than the 25-mm-diameter AAO discs utilized in this study, the drain chamber can be appropriately modified to fit the new specifications. However, there are certain aspects of the protocol that are necessary to ensure effective transfer results. 
The choice of 3D-printed material for the transfer tool and drain chamber proves to be important for the success of this protocol. Both the transfer tool and drain chamber should be printed with materials that do not continually shed material, as pieces of debris from shedding can ruin the integrity of the thin film membrane. PLA and inkjet printable resin were both determined to be optimal materials for this purpose. When coupled with thorough cleaning with deionized water and sonication, the 3D-printed parts should not produce particulates that would otherwise contaminate the samples. Additionally, the choice of 3D-printed material for the transfer tool is critical to prevent damage from any water tension bubbles arising from initial contact between the loading arm and the water in the drain chamber. PLA was determined to be the optimal material in this respect, and other hydrophilic polymers should work as well. Therefore, we highly recommend that PLA be used for the transfer tool, whereas the drain chamber should be printed with PLA and/or inkjet printable resin.
Another critical aspect of the protocol is the guidance of the meniscus in the transfer process, as the meniscus helps place the membrane onto the center of the receiver substrate. This can be controlled by the choice of volumetric flow rate of the syringe pump. Too fast of a withdrawing rate (greater than 5 mL/min for this protocol) will likely damage the membrane and prevent the meniscus in slowly guiding the membrane to the center of the receiver substrate. 2.5 mL/min has been determined to be an optimal rate for this protocol, as it preserves structural integrity of the membrane and high accuracy of centering and placement onto the receiver substrate, without sacrificing efficiency. Likewise, these parameters can still be adjusted based on the specific considerations of the project, especially if the geometrical specifications of the 3D-printed drain chamber are changed. 
While the described meniscus-guided/drain chamber transfer methodology helps to eliminate the creation of macroscale structural defects and severe plastic deformation in the transferred thin films, there is still the possibility of microscale defect structures within the membranes, such as fracturing and line/plane defects. However, these types of small-scale inhomogeneities might result from the initial fabrication of the samples rather than the transfer protocol itself. The role of such micro-scale defect structures on membrane performance is a topic of ongoing research. 
We have demonstrated a simple methodology based on 3D-printing and meniscus guidance to accurately and reproducibly control the transfer of thin film BCP membranes from donor silicon substrates to porous substrates. Results from optical inspection and image analysis software confirm the resultant high quality of placement. This protocol could be extended to any research application that requires the accurate transfer and uniform lamination of thin films to arbitrary porous substrates.

Thin film and nanomembrane-based devices have recently garnered wide interest due to their potential use in a broad range of applications, ranging from flexible photovoltaics and photonics, foldable displays, and wearable electronics1,2,3. A requirement for the fabrication of these various types of devices is the transfer of thin films to the surfaces of arbitrary substrates, which remains challenging due to the fragility of these films and the frequent production of macroscale defect structures, such as wrinkles, cracks, and tears, within the films after transfer4,5,6,7. Manual transfer by hand, tweezers, and wire loops are common methods of thin film transfer, but inevitably result in structural incongruities and plastic deformation8,9. Various types of thin film transfer methodologies have been explored such as: 1) polydimethylsiloxane (PDMS) stamp transfer, which involves the use of an elastomeric stamp to obtain the thin film from the donor substrate and subsequently transfer to the receiving substrate10, and 2) sacrificial layer transfer11, in which an etchant is used to selectively dissolve a sacrificial layer between the support substrate and the thin film, thereby lifting off the thin film. However, these techniques alone do not necessarily allow for thin film transfer without incurring damage to or defect formation within the thin films12.
Here, we present a novel, low-cost, and generalizable facile method based on sacrificial layer lift-off and meniscus-guided transfer within a custom-designed, 3D-printed drain chamber system, to mechanically place block copolymer (BCP) thin films onto the centers of porous substrates such as anodized aluminum oxide (AAO) discs with little-to-no incurred macroscale defect structures, such as wrinkles, tears, and cracks. In the present context, these transferred thin films can then be used as devices in water filtration studies, potentially after sequential infiltration synthesis (SIS) processing9. Image analysis of transferred films obtained from optical microscopy show that the meniscus-guided, drain-chamber system provides smooth, robust, and wrinkle-free samples. In addition, the images also demonstrate the system&#39;s ability to reliably place the thin film membranes onto the centers of the receiving substrates. Our results have significant implications for any type of device application requiring the transfer of thin film structures onto the surfaces of arbitrary porous substrates.

<table><tbody><tr><td>35% sodium polyacrylic acid solution</td><td>Sigma Aldrich</td><td>9003-01-4&amp;nbsp;&amp;nbsp;</td><td></td></tr><tr><td>Amicon Stirred Cell model 8010 10mL</td><td>Millipore</td><td>5121</td><td></td></tr><tr><td>Anodized aluminum oxide, 0.2u thickness, 25mm diameter</td><td>Sigma Aldrich</td><td>WHA68096022</td><td></td></tr><tr><td>o ring neoprene 117</td><td>Grainger</td><td>1BUV7</td><td></td></tr><tr><td>Objet500 Connex3 3D Printer</td><td>Stratasys</td><td></td><td></td></tr><tr><td>Onshape 3D software</td><td>onshape</td><td></td><td></td></tr><tr><td>Polylactic acid filament</td><td>Ultimaker</td><td></td><td></td></tr><tr><td>ultimaker3 3d filament printer</td><td>Ultimaker</td><td></td><td></td></tr><tr><td>Vero Family printable materials</td><td>Stratasys</td><td></td><td></td></tr></tbody></table>

procedure for the transfer of polymer films onto porous substrates with minimized defects

The fabrication of devices containing thin film composite membranes necessitates the transfer of these films onto the surfaces of arbitrary support substrates. Accomplishing this transfer in a highly controlled, mechanized, and reproducible manner can eliminate the creation of macroscale defect structures (e.g., tears, cracks, and wrinkles) within the thin film that compromise device performance and the usable area per sample. Here, we describe a general protocol for the highly controlled and mechanized transfer of a polymeric thin film onto an arbitrary porous support substrate for eventual use as a water filtration membrane device. Specifically, we fabricate a block copolymer (BCP) thin film on top of a sacrificial, water-soluble poly(acrylic acid) (PAA) layer and silicon wafer substrate. We then utilize a custom-designed, 3D-printed transfer tool and drain chamber system to deposit, lift-off, and transfer the BCP thin film onto the center of a porous anodized aluminum oxide (AAO) support disc. The transferred BCP thin film is shown to be consistently placed onto the center of the support surface due to the guidance of the meniscus formed between the water and the 3D-printed plastic drain chamber. We also compare our mechanized transfer-processed thin films to those that have been transferred by hand with the use of tweezers. Optical inspection and image analysis of the transferred thin films from the mechanized process confirm that little-to-no macroscale inhomogeneities or plastic deformations are produced, as compared to the multitude of tears and wrinkles produced from manual transfer by hand. Our results suggest that the proposed strategy for thin film transfer can reduce defects when compared to other methods across many systems and applications.

The BCP membrane samples were fabricated according to the previously described procedure9. The samples were placed onto the lip of the loading arm of the 3D-printed transfer tool (Figure 1, left) and subsequently lowered, with a laboratory jack, onto the entrance ramp of the 3D-printed drain chamber tool (Figure 1, right). A sacrificial layer of poly(acrylic acid) (PAA) between the BCP membrane and underlying donor silicon substrate was dissolved in the water within the drain chamber, resulting in a floating BCP membrane. Then, the syringe pump (Figure 2, bottom) was operated to withdraw water at a volumetric flow rate of 2.5 mL/min, resulting in a total transfer time of 10 min (assuming an initial 25 mL of water within the drain chamber system). This method of thin film transfer was compared to manual thin film transfer by hand and tweezers, as displayed in Figure 3.
Representative images of BCP thin film samples manually transferred onto porous AAO substrates are shown in Figure 4. These images illustrate the poor quality of the manual transfer method, as evidenced by the severe plastic deformation and macroscale defect structures present in the BCP membranes. All of the BCP membranes have wrinkled and fragmented after manual transfer, in addition to the distortion of the initial rectangular geometry of the diced BCP membranes. The human error introduced by manual transfer results in incomplete transfer of the membranes, as well as lack of centering and/or accuracy of placement onto the receiver AAO substrate-this will be further examined with image analysis software.
Representative images of BCP thin film samples transferred onto porous AAO substrates, using meniscus guidance and the drain chamber system, are shown in Figure5. Upon inspection, these images show a marked difference from those in Figure 4, as each membrane&#39;s rectangular geometry has been preserved. There appears to be complete and uniform lamination of the membrane onto the receiver AAO substrates, without any large plastic deformation effects observed. Furthermore, there appears to be a high accuracy of centering of the BCP membrane onto the receiver substrates, which will be confirmed with image analysis software.
To characterize the accuracy of placement and centering of the BCP membrane on the receiver AAO substrate, centroid image analysis was conducted using ImageJ analysis software. Specifically, the distance between the centroid of the BCP membrane and the centroid of the receiver AAO substrate was calculated for each sample. These values are reported in Table 1 and Table 2, corresponding to the manual transfer method and the meniscus-guided/drain-chamber method, respectively. The center-to-center distances for manually transferred samples (Table1) varied widely, with values ranging from 0.533 mm to 8.455 mm. The average center-to-center distance and standard deviation for the samples transferred with the manual method was 3.840 mm 2.788 mm. In contrast, the center-to-center distances for meniscus-guided/drain chamber transferred samples (Table 2) showed much less variation, with values ranging from 0.282 mm to 0.985 mm. The average center-to-center distance and standard deviation for the meniscus-guided/drain chamber transferred samples was 0.521 mm 0.258 mm. These results suggest that the meniscus-guided/drain chamber transfer system provides greater accuracy and reproducibility with respect to placement and centering of the BCP membrane on the receiver substrate. When coupled with the limited plastic deformation and macroscale defect structures observed in these samples (Figure 4), as compared to those manually transferred (Figure 3), the meniscus-guided transfer with the use of the drain chamber system proves to be an effective and robust protocol for the transfer of thin film membranes to arbitrary porous substrates.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/59554/59554fig1.jpg" /> 
Figure 1: Schematic depicting the design and assembly of the transfer tool (left) and drain chamber (right). The transfer tool (left) consists of two individual parts: the clamp and the loading arm, as labeled. The clamp attaches to any standard laboratory jack at (1) with a size #10 screw. The donor substrate containing the to-be-transferred thin film membrane is placed at (2). The drain chamber (right) consists of two individual parts: the top part and the bottom part, as labeled. The donor substrate is lowered onto the entrance ramp at (3). A neoprene O-ring (4) is provided to ensure a tight seal between the receiver substrate (5) and the bottom part of the drain chamber. Water flows through the chamber and exits at the outlet (6). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59554/59554fig1large.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/59554/59554fig2.jpg" /> 
Figure 2: Complete experimental setup. (Top) Pictured shows the complete 3D-printed transfer tool (clamp and loading arm) and drain chamber system. (Bottom) Pictured is a syringe held by a syringe pump with withdrawing functionality, connected to the drain chamber system. The syringe pump withdraws water from the drain chamber system and allows for meniscus-guided transfer of the nanomembrane to the receiver substrate. Also pictured is a glass beaker covering the drain chamber system to prevent dust and other foreign particulates from entering the drain chamber system. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59554/59554fig2large.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/59554/59554fig3.jpg" /> 
Figure 3: Manual thin film transfer method by hand and tweezers. In this method, the donor silicon substrate is slowly submerged into a bath of water, dissolving the sacrificial layer between the BCP membrane and substrate and releasing the BCP membrane into the bath. Subsequently, the user holds the receiver AAO substrate with a pair of tweezers and slowly &#34;scoops&#34; upward to place the BCP membrane onto the receiver AAO substrate. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59554/59554fig3large.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/59554/59554fig4.jpg" /> 
Figure 4: Optical images of manually transferred block copolymer (BCP) thin films. Photographs depicting the BCP membranes on top of the receiver AAO substrates (25 mm diameter), after manual transfer by hand and tweezers. Severe plastic deformation and macroscale defect structures are observed in the samples. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59554/59554fig4large.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/59554/59554fig5.jpg" /> 
Figure 5: Optical images of meniscus-guided transferred block copolymer (BCP) thin films, specifically with the use of the 3D-printed transfer/drain chamber tool. Photographs depicting the BCP membranes on top of the receiver AAO substrates (25 mm diameter), after meniscus-guided/drain chamber transfer. Uniform lamination, with limited plastic deformation, is observed in the samples. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59554/59554fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Sample</td>
			<td>Center-to-Center Distance (mm)</td>
		</tr>
		<tr>
			<td>1</td>
			<td>3.055</td>
		</tr>
		<tr>
			<td>2</td>
			<td>5.334</td>
		</tr>
		<tr>
			<td>3</td>
			<td>0.533</td>
		</tr>
		<tr>
			<td>4</td>
			<td>8.455</td>
		</tr>
		<tr>
			<td>5</td>
			<td>3.765</td>
		</tr>
		<tr>
			<td>6</td>
			<td>1.895</td>
		</tr>
	</tbody>
</table>
Table 1: Center-to-center distances for manually transferred samples. These values describe the distances between the center of the BCP membrane and the center of the receiver AAO substrate, determined by the centroid function of ImageJ analysis software. The center-to-center distance was 3.840 2.788 mm (mean &#177; SD).
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Sample</td>
			<td>Center-to-Center Distance (mm)</td>
		</tr>
		<tr>
			<td>1</td>
			<td>0.527</td>
		</tr>
		<tr>
			<td>2</td>
			<td>0.985</td>
		</tr>
		<tr>
			<td>3</td>
			<td>0.597</td>
		</tr>
		<tr>
			<td>4</td>
			<td>0.282</td>
		</tr>
		<tr>
			<td>5</td>
			<td>0.438</td>
		</tr>
		<tr>
			<td>6</td>
			<td>0.300</td>
		</tr>
	</tbody>
</table>
Table 2: Center-to-center distances for meniscus-guided/drain chamber transferred samples. These values describe the distances between the center of the BCP membrane and the center of the receiver AAO substrate, determined by the centroid function of ImageJ analysis software. The center-to-center distance was 0.521 0.258 mm (mean &#177; SD).

Watch this Scientific Journal Video about Procedure for the Transfer of Polymer Films Onto Porous Substrates with Minimized Defects at JoVE.com

Procedure for the Transfer of Polymer Films Onto Porous Substrates with Minimized Defects

We present a procedure for highly controlled and wrinkle-free transfer of block copolymer thin films onto porous support substrates using a 3D-printed drain chamber. The drain chamber design is of general relevance to all procedures involving transfer of macromolecular films onto porous substrates, which is normally done by hand in an irreproducible fashion.

The fabrication of devices containing thin film composite membranes necessitates the transfer of these films onto the surfaces of arbitrary support ...

procedure-for-transfer-polymer-films-onto-porous-substrates-with

Nanyang Technological University

Research

JoVE Journal

Engineering

6.5K Views.  University of Chicago. Om polymeerdunne films in membraantoepassingen te bestuderen, moeten materialen worden overgebracht van een gepolijst, glad substraat naar poreuze substraten op een manier die de film niet vouwt, kreukt, scheurt of plastisch vervormt. Deze video beschrijft een 3D afdrukbare afvoerkamer ontworpen om dit doel te bereiken en betreft stappen vier tot en met zes in de processtroom die hier wordt getoond. De monsters die in dit werk worden gebruikt, bestaan uit siliciumwafersubstraten waarin een st...

Video: Procedure for the Transfer of Polymer Films Onto Porous Substrates with Minimized Defects

Simulation, Fabrication and Characterization of THz Metamaterial Absorbers

Metamaterials (MM), artificial materials engineered to have properties that may not be found in nature, have been widely explored since the first theoretical1 and experimental demonstration2 of their unique properties. MMs can provide a highly controllable electromagnetic response, and to date have been demonstrated in every technologically relevant spectral range including the optical3, near IR4, mid IR5 , THz6 , mm-wave7 , microwave8 and radio9 bands. Applications include perfect lenses10, sensors11, telecommunications12, invisibility cloaks13 and filters14,15. We have recently developed single band16, dual band17 and broadband18 THz metamaterial absorber devices capable of greater than 80% absorption at the resonance peak. The concept of a MM absorber is especially important at THz frequencies where it is difficult to find strong frequency selective THz absorbers19. In our MM absorber the THz radiation is absorbed in a thickness of ~ &lambda;/20, overcoming the thickness limitation of traditional quarter wavelength absorbers. MM absorbers naturally lend themselves to THz detection applications, such as thermal sensors, and if integrated with suitable THz sources (e.g. QCLs), could lead to compact, highly sensitive, low cost, real time THz imaging systems.

This protocol outlines the simulation, fabrication and characterization of THz metamaterial absorbers. Such absorbers, when coupled with an appropriate sensor, have applications in THz imaging and spectroscopy.

Metamaterials (MM),  artificial materials engineered to have properties that may not be found in  nature, have been widely explored since the first ...

Fabrication of Large-area Free-standing Ultrathin Polymer Films

This procedure describes a method for the fabrication of large-area and ultrathin free-standing polymer films. Typically, ultrathin films are prepared using either sacrificial layers, which may damage the film or affect its mechanical properties, or they are made on freshly cleaved mica, a substrate that is difficult to scale. Further, the size of ultrathin film is typically limited to a few square millimeters. In this method, we modify a surface with a polyelectrolyte that alters the strength of adhesion between polymer and deposition substrate. The polyelectrolyte can be shown to remain on the wafer using spectroscopy, and a treated wafer can be used to produce multiple films, indicating that at best minimal amounts of the polyelectrolyte are added to the film. The process has thus far been shown to be limited in scalability only by the size of the coating equipment, and is expected to be readily scalable to industrial processes. In this study, the protocol for making the solutions, preparing the deposition surface, and producing the films is described.

We describe a method for the fabrication of large-area (up to 13 cm diameter) and ultrathin (as thin as 8 nm) polymer films. Instead of using a sacrificial interlayer to delaminate the film from its substrate, we use a self-limiting surface treatment suitable for arbitrarily large areas.

This procedure describes a method for the fabrication of large-area and ultrathin free-standing polymer films.  Typically, ultrathin films are prepared ...

Chemistry

Layer-by-layer Synthesis and Transfer of Freestanding Conjugated Microporous Polymer Nanomembranes

CMP as large surface area materials have attracted growing interest recently, due to their high variability in the incorporation of functional groups in combination with their outstanding thermal and chemical stability, and low densities. However, their insoluble nature causes problems in their processing since usually applied techniques such as spin coating are not available. Especially for membrane applications, where the processing of CMP as thin films is desirable, the processing problems have hindered their commercial application.
Here we describe the interfacial synthesis of CMP thin films on functionalized substrates via molecular layer-by-layer (l-b-l) synthesis. This process allows the preparation of films with desired thickness and composition and even desired composition gradients.
The use of sacrificial supports allows the preparation of freestanding membranes by dissolution of the support after the synthesis. To handle such ultra-thin freestanding membranes the protection with sacrificial coatings showed great promise, to avoid rupture of the nanomembranes. To transfer the nanomembranes to the desired substrate, the coated membranes are upfloated at the air-liquid interface and then transferred via dip coating.

In this paper we describe the interfacial synthesis of conjugated microporous polymers (CMP) on sacrificial substrates, and the dissolution of the substrate for the preparation of freestanding CMP nanomembranes. In addition, we will describe how the fragile nanomembranes can be transferred to other substrates.

CMP as large surface area materials have attracted growing interest recently, due to their high variability in the incorporation of functional groups in ...

Integration of Light Trapping Silver Nanostructures in Hydrogenated Microcrystalline Silicon Solar Cells by Transfer Printing

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly known as plasmonic effects, play an important role. Research in this field has, however, been impeded owing to the difficulty of fabricating devices containing the desired functional metal nanostructures. In order to provide a viable strategy to this issue, we herein show a transfer printing-based approach that allows the quick and low-cost integration of designed metal nanostructures with a variety of device architectures, including solar cells. Nanopillar poly(dimethylsiloxane) (PDMS) stamps were fabricated from a commercially available nanohole plastic film as a master mold. On this nanopatterned PDMS stamps, Ag films were deposited, which were then transfer-printed onto block copolymer (binding layer)-coated hydrogenated microcrystalline Si (&#181;c-Si:H) surface to afford ordered Ag nanodisk structures. It was confirmed that the resulting Ag nanodisk-incorporated &#181;c-Si:H solar cells show higher performances compared to a cell without the transfer-printed Ag nanodisks, thanks to plasmonic light trapping effect derived from the Ag nanodisks. Because of the simplicity and versatility, further device application would also be feasible thorough this approach.

A viable transfer printing-based methodology to introduce plasmonic metal nanostructures in solar cells is described. Using nanopillar poly(dimethylsiloxane) stamps, an Ag-based ordered nanodisk array was integrated with standard hydrogenated microcrystalline Si solar cells, which led to improved device performances due to plasmonic light trapping.

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly ...

Reactive Vapor Deposition of Conjugated Polymer Films on Arbitrary Substrates

We demonstrate a method of conformally coating conjugated polymers on arbitrary substrates using a custom-designed, low-pressure reaction chamber. Conductive polymers, poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(3,4-propylenedioxythiophene) (PProDOT), and a semiconducting polymer, poly(thieno[3,2-b]thiophene) (PTT), were deposited on unconventional highly-disordered and textured substrates with high surface areas, such as paper, towels and fabrics. This reported deposition chamber is an improvement of previous vapor reactors because our system can accommodate both volatile and nonvolatile monomers, such as 3,4-propylenedioxythiophene and thieno[3,2-b]thiophene. Utilization of both solid and liquid oxidants are also demonstrated. One limitation of this method is that it lacks sophisticated in situ thickness monitors. Polymer coatings made by the commonly used solution-based coating methods, such as spin-coating and surface grafting, are often not uniform or susceptible to mechanical degradation. This reported vapor phase deposition method overcomes those drawbacks and is a strong alternative to common solution-based coating methods. Notably, polymer films coated by the reported method are uniform and conformal on rough surfaces, even at a micrometer scale. This feature allows for future application of vapor deposited polymers in electronics devices on flexible and highly textured substrates.

This paper presents a protocol for reactive vapor deposition of poly(3,4-ethylenedioxythiophene), poly(3,4-propylenedioxythiophene), and poly(thieno[3,2-b]thiophene) films on glass slides and rough substrates, such as textiles and paper.

We demonstrate a method of conformally coating conjugated polymers on arbitrary substrates using a custom-designed, low-pressure reaction chamber. ...

Preparation of Light-responsive Membranes by a Combined Surface Grafting and Postmodification Process

In order to modify the surface tension of commercial available track-edged polymer membranes, a procedure of surface-initiated polymerization is presented. The polymerization from the membrane surface is induced by plasma treatment of the membrane, followed by reacting the membrane surface with a methanolic solution of 2-hydroxyethyl methacrylate (HEMA). Special attention is given to the process parameters for the plasma treatment prior to the polymerization on the surface. For example, the influence of the plasma-treatment on different types of membranes (e.g.&#160;polyester, polycarbonate, polyvinylidene fluoride) is studied. Furthermore, the time-dependent stability of the surface-grafted membranes is shown by contact angle measurements. When grafting poly(2-hydroxyethyl methacrylate) (PHEMA) in this way, the surface can be further modified by esterification of the alcohol moiety of the polymer with a carboxylic acid function of the desired substance. These reactions can therefore be used for the functionalization of the membrane surface. For example, the surface tension of the membrane can be changed or a desired functionality as the presented light-responsiveness can be inserted. This is demonstrated by reacting PHEMA with a carboxylic acid functionalized spirobenzopyran unit which leads to a light-responsive membrane. The choice of solvent plays a major role in the postmodification step and is discussed in more detail in this paper. The permeability measurements of such functionalized membranes are performed using a Franz cell with an external light source. By changing the wavelength of the light from the visible to the UV-range, a change of permeability of aqueous caffeine solutions is observed.

A plasma-induced polymerization procedure is described for the surface-initiated polymerization on polymer membranes. Further postmodification of the grafted polymer with photochromic substances is presented with a protocol of conducting permeability measurements of light-responsive membranes.

In order to modify the surface tension of commercial available track-edged polymer membranes, a procedure of surface-initiated polymerization is ...

Bioengineering

Fabricating Reactive Surfaces with Brush-like and Crosslinked Films of Azlactone-Functionalized Block Co-Polymers

In this paper, fabrication methods that generate novel surfaces using the azlactone-based block co-polymer, poly (glycidyl methacrylate)-block-poly (vinyl dimethyl azlactone) (PGMA-b-PVDMA), are presented. Due to the high reactivity of azlactone groups towards amine, thiol, and hydroxyl groups, PGMA-b-PVDMA surfaces can be modified with secondary molecules to create chemically or biologically functionalized interfaces for a variety of applications. Previous reports of patterned PGMA-b-PVDMA interfaces have used traditional top-down patterning techniques that generate non-uniform films and poorly controlled background chemistries. Here, we describe customized patterning techniques that enable precise deposition of highly uniform PGMA-b-PVDMA films in backgrounds that are chemically inert or that have biomolecule-repellent properties. Importantly, these methods are designed to deposit PGMA-b-PVDMA films in a manner that completely preserves azlactone functionality through each processing step. Patterned films show well-controlled thicknesses that correspond to polymer brushes (~90 nm) or to highly crosslinked structures (~1-10 &#956;m). Brush patterns are generated using either the parylene lift-off or interface directed assembly methods described and are useful for precise modulation of overall chemical surface reactivity by adjusting either the PGMA-b-PVDMA pattern density or the length of the VDMA block. In contrast, the thick, crosslinked PGMA-b-PVDMA patterns are obtained using a customized micro-contact printing technique and offer the benefit of higher loading or capture of secondary material due to higher surface area to volume ratios. Detailed experimental steps, critical film characterizations, and trouble-shooting guides for each fabrication method are discussed.

Surface fabrication methods for patterned deposition of nanometer thick brushes or micron thick, crosslinked films of an azlactone block co-polymer are reported. Critical experimental steps, representative results, and limitations of each method are discussed. These methods are useful for creating functional interfaces with tailored physical features and tunable surface reactivity.

In this paper, fabrication methods that generate novel surfaces using the azlactone-based block co-polymer, poly (glycidyl methacrylate)-block-poly (vinyl ...

Thin Film Composite Silicon Elastomers for Cell Culture and Skin Applications: Manufacturing and Characterization

In this protocol, we present methods to fabricate thin elastomer composite films for advanced cell culture applications and for the development of skin adhesives. Two different poly-(dimethyl siloxanes) (PDMS and soft skin adhesive (SSA)), have been used for in depth investigation of biological effects and adhesive characteristics. The composite films consist of a flexible backing layer and an adhesive top coating. Both layers have been manufactured by doctor blade application technique. In the present investigation, the adhesive behavior of the composite films has been investigated as a function of the layer thickness or a variation of the Young&#39;s modulus of the top layer. The Young&#39;s modulus of PDMS has been changed by varying the base to crosslinker mixing ratio. In addition, the thickness of SSA films has been varied from approx. 16 &#181;m to approx. 320 &#181;m. Scanning electron microscopy (SEM) and optical microscopy have been used for thickness measurements. The adhesive properties of elastomer films depend strongly on the film thickness, the Young&#39;s modulus of the polymers and surface characteristics. Therefore, normal adhesion of these films on glass substrates exhibiting smooth and rough surfaces has been investigated. Pull-off stress and work of separation are dependent on the mixing ratio of silicone elastomers.
Additionally, the thickness of the soft skin adhesive placed on top of a supportive backing layer has been varied in order to produce patches for skin applications. Cytotoxicity, proliferation and cellular adhesion of L929 murine fibroblasts on PDMS films (mixing ratio 10:1) and SSA films (mixing ratio 50:50) have been conducted. We have shown here, for the first time, the side by side comparison of thin composite films manufactured of both polymers and present the investigation of their biological- and adhesive properties.

A protocol for the manufacturing process of polymeric thin film composite structures possessing either different Young&#39;s moduli or thicknesses is presented. Films are produced for advanced cell culture studies or as skin adhesives.

In this protocol, we present methods to fabricate thin elastomer composite films for advanced cell culture applications and for the development of skin ...

Developmental Biology

Fabricating van der Waals Heterostructures with Precise Rotational Alignment

In this work we describe a technique for creating new crystals (van der Waals heterostructures) by stacking distinct ultrathin layered 2D materials. We demonstrate not only lateral control but, importantly, also control over the angular alignment of adjacent layers. The core of the technique is represented by a home-built transfer setup which allows the user to control the position of the individual crystals involved in the transfer. This is achieved with sub-micrometer (translational) and sub-degree (angular) precision. Prior to stacking them together, the isolated crystals are individually manipulated by custom-designed moving stages that are controlled by a programmed software interface. Moreover, since the entire transfer setup is computer controlled, the user can remotely create precise heterostructures without coming into direct contact with the transfer setup, labeling this technique as &#8220;hands-free&#8221;. In addition to presenting the transfer set-up, we also describe two techniques for preparing the crystals that are subsequently stacked.

In this work we describe a technique that is used to create new crystals (van der Waals heterostructures) by stacking ultrathin layered 2D materials with precise control over position and relative orientation.

In this work we describe a technique for creating new crystals (van der Waals heterostructures) by stacking distinct ultrathin layered 2D materials. We ...

A Femtoliter Droplet Array for Massively Parallel Protein Synthesis from Single DNA Molecules

Advances in spatial resolution and detection sensitivity of scientific instrumentation make it possible to apply small reactors for biological and chemical research. To meet the demand for high-performance microreactors, we developed a femtoliter droplet array (FemDA) device and exemplified its application in massively parallel cell-free protein synthesis (CFPS) reactions. Over one million uniform droplets were readily generated within a finger-sized area using a two-step oil-sealing protocol. Every droplet was anchored in a femtoliter microchamber composed of a hydrophilic bottom and a hydrophobic sidewall. The hybrid hydrophilic-in-hydrophobic structure and the dedicated sealing oils and surfactants are crucial for stably retaining the femtoliter aqueous solution in the femtoliter space without evaporation loss. The femtoliter configuration and the simple structure of the FemDA device allowed minimal reagent consumption. The uniform dimension of the droplet reactors made large-scale quantitative and time-course measurements convincing and reliable. The FemDA technology correlated the protein yield of the CFPS reaction with the number of DNA molecules in each droplet. We streamlined the procedures about the microfabrication of the device, the formation of the femtoliter droplets, and the acquisition and analysis of the microscopic image data. The detailed protocol with the optimized low running cost makes the FemDA technology accessible to everyone who has standard cleanroom facilities and a conventional fluorescence microscope in their own place.

The overall goal of the protocol is to prepare over one million ordered, uniform, stable, and biocompatible femtoliter droplets on a 1 cm2 planar substrate that can be used for cell-free protein synthesis.

Procedure for the Transfer of Polymer Films Onto Porous Substrates with Minimized Defects

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