Name: Layer-by-layer Synthesis and Transfer of Freestanding Conjugated Microporous Polymer Nanomembranes (Video) | JoVE Journal
Uploaded: 2015-12-15T13:00:00.000+00:00
Duration: 9 min 9 s
Description: Learn layer-by-layer synthesis of freestanding conjugated microporous polymer nanomembranes using sacrificial substrates. This method enables uniform membrane production and transfer for membrane separation and organic electronics applications.

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The authors have no acknowledgements.

1. Synthesis of CMP Thin Films through Sequential Addition
<ol>
	<li>Self-assembled monolayer (SAM) functionalization of gold on mica.
	<ol>
		<li>Prepare 1 mM solution of 11-thioacetyl-undecane acid-propargyl amide14 in ethanol (SAM-solution). Mix using ultrasonic bath till solution is clear. Protect the bottle from light using aluminum foil.</li>
		<li>Obtain gold coated mica wafer under argon. After withdrawal from the storage container immerse the mica wafer directly to the SAM-solution for 18 hr.</li>
		<li>Take the prepared Au-mica wafer out of the SAM-solution, rinse with ethanol and dry under nitrogen stream. Afterwards store the substrate protected from light and under inert gas.</li>
	</ol>
	</li>
	<li>Precursor solutions.
	<ol>
		<li>Weigh 18.64 mg Cu-catalyst (Tetrakis(acetonitrile)copper(I)hexafluoro-phosphate), 20.83 mg tetraphenylmethane (TPM)-alkyne and 24.22 mg TPM-azide and fill each component into a separate Schlenk flask. See Figure 1 for TPM-alkyne and TPM-azide, the synthesis is described in Reference15. Evacuate and refill with inert gas (N2 or argon) 3 times.</li>
		<li>Add 25 ml water-free tetrahydrofuran (THF) to each Schlenk flask. Protect the flasks with TPM-azide and TPM-alkyne from light using aluminum foil.</li>
	</ol>
	</li>
	<li>Prepare apparatus for CMP fabrication. 
	Note: The synthesis apparatus is shown in Figure 2.
	<ol>
		<li>Use a 250 ml one neck round bottom flask. Fill in 130 ml THF. Put the prepared substrate coated with alkyne terminated SAM in the sample compartment. Use a sample holder, so that the substrate is standing upright.</li>
		<li>Connect the apparatus to the Schlenk line via the junction on top of the reflux cooler.</li>
		<li>Evacuate and ventilate with inert gas 3 times.</li>
	</ol>
	</li>
	<li>Sequential addition under inert conditions.
	<ol>
		<li>Set the heater to 90 &#176;C and wait till the THF is refluxing.</li>
		<li>Let out THF from the sample compartment over the outlet at the bottom of the sample compartment. Close the outlet.</li>
		<li>Give 1 ml of the prepared TPM-azide solution and 0.5 ml of the Cu(I) catalyst solution to the sample compartment via the screw cap with septum. Use a syringe with a hollow needle to transfer the solutions sequentially from the Schlenk flask to the reaction apparatus. Note: The sequence has no influence to the reaction.</li>
		<li>Wait approximately 30 min.</li>
		<li>Let out the reaction solution over the outlet at the bottom of the sample compartment. Close the outlet and collect the condensed THF for rinsing the sample. Wait approximately 30 min.</li>
		<li>Let out the rinsing solution over the outlet at the bottom of the sample compartment. Close the outlet.</li>
		<li>Give 1 ml of the prepared TPM-alkyne solution and 0.5 ml of the Cu(I) catalyst solution to the sample compartment via the screw cap with septum. Use a syringe with a hollow needle to transfer the solutions sequentially from the Schlenk flask to the reaction apparatus. Note: The sequence has no influence to the reaction.</li>
		<li>Wait approximately 30 min.</li>
		<li>Let out the reaction solution over the outlet at the bottom of the sample compartment. Close the outlet and collect the condensed THF for rinsing the sample. Wait approximately 30 min.</li>
		<li>Repeat steps 1.4.3 to 1.4.9 until the desired amount of layers is reached. Note: One layer is approximately 1 nm thick.</li>
		<li>Take out the CMP-coated mica substrate, rinse it with THF, ethanol and dry it under nitrogen stream.</li>
	</ol>
	</li>
</ol>
2. Transfer of CMP Nanomembranes
<ol>
	<li>Poly(methyl methacrylate) (PMMA) solution.
	<ol>
		<li>Prepare a solution of 4% (wt) PMMA (M 996 kDa) in ethyl acetate. Dissolve the PMMA using ultrasonic bath till the solution is clear.</li>
	</ol>
	</li>
	<li>Spin coating of PMMA solution.
	<ol>
		<li>Set the spin coater to ramp time 10 sec from 0 to 4,000 rpm, holding time 40 sec and ramp time 10 sec from 4,000 to 0 rpm.</li>
		<li>Place the CMP coated mica substrate on the spin coater and put the PMMA solution on the wafer till it is completely covered. Start the spin coater.</li>
		<li>After spin coating is completed, put the sample for 5 min on a heating plate at 90 &#176;C.</li>
		<li>Cut off 1 mm from each edge of the coated mica substrate. Use a scissor to cut the edges.</li>
	</ol>
	</li>
	<li>Transfer of PMMA coated CMP nanomembrane.
	<ol>
		<li>Prepare solution of I2/KI/H2O (1:4:40 m/m/m) and of KI/H2O (1:10 m/m).</li>
		<li>Fill the I2/KI H2O solution in a 150 ml crystallizing dish and fill the KI/H2O solution in a 100 ml crystallizing dish. Put the PMMA coated CMP gold on mica substrate, with mica in contact to solution, on top of the I2/KI/H2O solution. Be careful that it does not sink. Wait at least 5 min.</li>
		<li>Put the PMMA coated CMP gold mica substrate from the I2/KI/H2O solution on top of the KI/H2O solution, with mica in contact to solution. Be careful that it does not sink. Wait at least 5 min.</li>
		<li>Fill distilled water in a 250 ml crystallizing dish. Strip off the PMMA/CMP/gold film from the mica. Do this by slightly immersing the substrate, beginning from one edge, in distilled water. Hold the substrate so that the mica is pointing to the water. Note: The procedure is shown in Figure 3.</li>
		<li>Dip-coat the PMMA/CMP/gold on the silicon wafer. Do this by approaching the PMMA/CMP/gold slowly with the wafer until it touches edge of the swimming PMMA/CMP/gold membrane. Pull out the silicon wafer slowly, once the Si-wafer is in contact with the PMMA/CMP/gold membrane.</li>
		<li>Strip the PMMA/CMP/gold film off from the silicon wafer. Do this by slightly immersing the substrate, beginning from one edge, in the I2/KI/H2O solution. Wait 15 min.</li>
		<li>After the gold is completely etched, transfer the PMMA/CMP membrane to water via the silicon wafer. Wait 15 min.</li>
		<li>Repeat step 2.3.7 three times to wash the membrane with water.</li>
		<li>Transfer the washed PMMA/CMP membrane to the desired substrate, e.g., a microscope slide or a gold coated silicon wafer, via the method mentioned in step 2.3.5. Let the PMMA/CMP substrate dry in air for at least 2 hr.</li>
	</ol>
	</li>
	<li>Dissolution of PMMA.
	<ol>
		<li>Put the PMMA/CMP substrate in acetone. Wait 30 min. Take out the substrate and rinse it with acetone.</li>
		<li>Repeat step 2.4.1 three times.</li>
		<li>Let the CMP substrate dry for at least 2 hr.</li>
	</ol>
	</li>
</ol>

<ol><li>Lindemann, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Preparation+of+Freestanding+Conjugated+Microporous+Polymer+Nanomembranes+for+Gas+Separation%5BTitle%5D)+AND+%22Chemistry+of+Materials%22%5BJournal%5D)">Preparation of Freestanding Conjugated Microporous Polymer Nanomembranes for Gas Separation.</a> Chemistry of Materials. 26 (24), 7193-71 (2014).</li>
<li>Kim, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Preparation+of+Ultrathin+Films+of+Molecular+Networks+through+Layer-by-Layer+Cross-Linking+Polymerization+of+Tetrafunctional+Monomers%5BTitle%5D)+AND+%22Macromolecules%22%5BJournal%5D)">Preparation of Ultrathin Films of Molecular Networks through Layer-by-Layer Cross-Linking Polymerization of Tetrafunctional Monomers.</a> Macromolecules. 44 (18), 7092-7095 (2011).</li>
<li>Vonhören, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Ultrafast+Layer-by-Layer+Assembly+of+Thin+Organic+Films+Based+on+Triazolinedione+Click+Chemistry%5BTitle%5D)+AND+%22ACS+Macro+Letters%22%5BJournal%5D)">Ultrafast Layer-by-Layer Assembly of Thin Organic Films Based on Triazolinedione Click Chemistry.</a> ACS Macro Letters. 4 (3), 331-334 (2015).</li>
<li>Shekhah, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Step-by-Step+Route+for+the+Synthesis+of+Metal%E2%88%92Organic+Frameworks%5BTitle%5D)+AND+%22Journal+of+the+American+Chemical+Society%22%5BJournal%5D)">Step-by-Step Route for the Synthesis of Metal−Organic Frameworks.</a> Journal of the American Chemical Society. 129 (49), 15118-15119 (2007).</li>
<li>Shekhah, O., Wang, H., Zacher, D., Fischer, R. A., Wöll, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Growth+Mechanism+of+Metal%E2%80%93Organic+Frameworks%3A+Insights+into+the+Nucleation+by+Employing+a+Step-by-Step+Route%5BTitle%5D)+AND+%22Angewandte+Chemie+International+Edition%22%5BJournal%5D)">Growth Mechanism of Metal–Organic Frameworks: Insights into the Nucleation by Employing a Step-by-Step Route.</a> Angewandte Chemie International Edition. 48 (27), 5038-5041 (2009).</li>
<li>Shekhah, O., Liu, J., Fischer, R. A., Wöll, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((MOF+thin+films%3A+existing+and+future+applications%5BTitle%5D)+AND+%22Chemical+Society+Reviews%22%5BJournal%5D)">MOF thin films: existing and future applications.</a> Chemical Society Reviews. 40 (2), 1081-1106 (2011).</li>
<li>Liu, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Deposition+of+Metal-Organic+Frameworks+by+Liquid-Phase+Epitaxy%3A+The+Influence+of+Substrate+Functional+Group+Density+on+Film+Orientation%5BTitle%5D)+AND+%22Materials%22%5BJournal%5D)">Deposition of Metal-Organic Frameworks by Liquid-Phase Epitaxy: The Influence of Substrate Functional Group Density on Film Orientation.</a> Materials. 5 (9), 1581-1592 (2012).</li>
<li>Such, G. K., Quinn, J. F., Quinn, A., Tjipto, E., Caruso, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Assembly+of+Ultrathin+Polymer+Multilayer+Films+by+Click+Chemistry%5BTitle%5D)+AND+%22Journal+of+the+American+Chemical+Society%22%5BJournal%5D)">Assembly of Ultrathin Polymer Multilayer Films by Click Chemistry.</a> Journal of the American Chemical Society. 128 (29), 9318-9319 (2006).</li>
<li>Ai, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Carbon+Nanomembranes+%28CNMs%29+Supported+by+Polymer%3A+Mechanics+and+Gas+Permeation%5BTitle%5D)+AND+%22Advanced+Materials%22%5BJournal%5D)">Carbon Nanomembranes (CNMs) Supported by Polymer: Mechanics and Gas Permeation.</a> Advanced Materials. 26 (21), 3421-3426 (2014).</li>
<li>Jiang, J. -X., Cooper, A. I. in Functional Metal-Organic Frameworks: Gas Storage, Separation and Catalysis. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aJiang%2C+J-X+%22Topics+in+Current+Chemistry.+%28ed+Martin+Schr%C3%B6der%29+Ch%22">Topics in Current Chemistry. (ed Martin Schröder) Ch</a>. 293, Springer. Berlin Heidelberg. 1-33 (2010).</li>
<li>Dawson, R., Cooper, A. I., Adams, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Nanoporous+organic+polymer+networks%5BTitle%5D)+AND+%22Progress+in+Polymer+Science%22%5BJournal%5D)">Nanoporous organic polymer networks.</a> Progress in Polymer Science. 37 (4), 530-563 (2012).</li>
<li>Muller, T., Bräse, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Click+Chemistry+Finds+Its+Way+into+Covalent+Porous+Organic+Materials%5BTitle%5D)+AND+%22Angewandte+Chemie+International+Edition%22%5BJournal%5D)">Click Chemistry Finds Its Way into Covalent Porous Organic Materials.</a> Angewandte Chemie International Edition. 50 (50), 11844-11845 (2011).</li>
<li>Tsotsalas, M., Addicoat, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Covalently+linked+organic+networks%5BTitle%5D)+AND+%22Frontiers+in+Materials%22%5BJournal%5D)">Covalently linked organic networks.</a> Frontiers in Materials. 2, (2015).</li>
<li>Kleinert, M., Winkler, T., Terfort, A., Lindhorst, T. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+modular+approach+for+the+construction+and+modification+of+glyco-SAMs+utilizing+1%2C3-dipolar+cycloaddition%5BTitle%5D)+AND+%22Organic+%26+Biomolecular+Chemistry%22%5BJournal%5D)">A modular approach for the construction and modification of glyco-SAMs utilizing 1,3-dipolar cycloaddition.</a> Organic & Biomolecular Chemistry. 6 (12), 2118-2132 (2008).</li>
<li>Plietzsch, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Four-fold+click+reactions%3A+Generation+of+tetrahedral+methane-+and+adamantane-based+building+blocks+for+higher-order+molecular+assemblies%5BTitle%5D)+AND+%22Organic+%26+Biomolecular+Chemistry%22%5BJournal%5D)">Four-fold click reactions: Generation of tetrahedral methane- and adamantane-based building blocks for higher-order molecular assemblies.</a> Organic & Biomolecular Chemistry. 7, (2009).</li>
<li>Greenler, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Infrared+Study+of+Adsorbed+Molecules+on+Metal+Surfaces+by+Reflection+Techniques%5BTitle%5D)+AND+%22The+Journal+of+Chemical+Physics%22%5BJournal%5D)">Infrared Study of Adsorbed Molecules on Metal Surfaces by Reflection Techniques.</a> The Journal of Chemical Physics. 44 (1), (1966).</li>
</ol>

The authors have nothing to disclose.

For the synthesis of the CMP-film the solution of the catalyst has to be fresh. A broken catalyst (i.e., oxidized) is indicated by a blue coloration of the solution. The fresh solution is colorless.
A crucial point is to cut the edges of the mica substrate after spin coating PMMA. Also defects in the substrate should be cut, i.e., each spot were the PMMA can come in contact with the mica substrate, because of a missing gold layer. Otherwise the gold layer cannot be stripped o...

The preparation of ultra-thin polymer membranes is of high interest for applications in gas separation and nanofiltration. Challenges in the synthesis are represented by (a) the control of the membrane thickness and the homogeneity and (b) transfer of such fragile membranes. To overcome challenge (a), molecular layer-by-layer synthesis1 has shown great promise in controlling the thickness and homogeneity of thin films grown at the solid-liquid interface.2,3 Controlling the number of layers linearly controls the film thickness. The l-b-l method has been successfully used to fabricate surface mounted metal organic frameworks (SURMOFs),4-7 also the synthesis of thin polymer films via l-b-l reaction of polymer chains was demonstrated.8 The challenge (b) concerns the handling of these ultra-thin membranes. To avoid rupture or wrinkling of the nanomembranes sacrificial supports of coatings have shown great promise. 9
Here we will present a detailed protocol for synthesis of conjugated microporous polymer (CMP)10-13 thin films through sequential addition of the molecular building blocks, with desired thickness and composition. The preparation of free-standing CMP nanomembranes is achieved by using a sacrificial support. To handle and transfer the CMP nanomembranes to other supports we will describe a simple protocol to protect the membranes with sacrificial coatings and their upfloating to the liquid air interface and subsequent transfer using dip-coating.

<table><tbody><tr><td>Acetone</td><td>VWR BDH Prolabo</td><td>20066.330</td><td>AnalR NORMAPUR</td></tr><tr><td>Potassium iodide</td><td>VWR BDH Prolabo</td><td>26846.292</td><td>AnalR NORMAPUR</td></tr><tr><td>Ethyl acetate</td><td>VWR BDH Prolabo</td><td>23882.321</td><td>AnalR NORMAPUR</td></tr><tr><td>Tetrahydrofuran (THF)</td><td>VWR BDH Prolabo</td><td>28559.320</td><td>HiPerSolv CHROMANORM</td></tr><tr><td>THF waterfree</td><td>Merck Millipore</td><td>1.08107.1001</td><td>SeccoSolv</td></tr><tr><td>Iodine</td><td>Sigma-Aldrich</td><td>20,777-2</td><td></td></tr><tr><td>Tetrakis(acetonitrile) copper(I) hexafluoro-phosphate</td><td>Sigma-Aldrich</td><td>346276-5G</td><td></td></tr><tr><td>Poly(methyl methacrylate) 996 kDa (PMMA)</td><td>Sigma-Aldrich</td><td>182265-25G</td><td></td></tr><tr><td>1.1.1.1 Methanetetrayltetrakis(4-azidobenzene) (TPM-azide)</td><td></td><td></td><td>Provided by AK Prof. Br&amp;auml;se. Institute of organic chemistry, Karlsruhe Institute of Technology. Synthesized according to &lt;sup&gt;9&lt;/sup&gt;.</td></tr><tr><td>1.1.1.1 Methanetetrayltetrakis(4-ethinylenebenzene) (TPM-alkyne)</td><td></td><td></td><td>Provided by AK Prof. Br&amp;auml;se. Institute of organic chemistry, Karlsruhe Institute of Technology. Synthesized according to &lt;sup&gt;9&lt;/sup&gt;.</td></tr><tr><td>11-thioacetyl-undecaneacid propargylamide</td><td></td><td></td><td>Provided by AK Prof. Br&amp;auml;se. Institute of organic chemistry, Karlsruhe Institute of Technology. Synthesized according to &lt;sup&gt;8&lt;/sup&gt;.</td></tr><tr><td>gold/titan coated silicium-wafer</td><td>Georg Albert PVD, 76857 Silz, Germany</td><td></td><td></td></tr><tr><td>gold coated mica</td><td>Georg Albert PVD, 76857 Silz, Germany</td><td></td><td></td></tr></tbody></table>

layer-by-layer synthesis and transfer of freestanding conjugated microporous polymer nanomembranes

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.

The membranes are characterized by infrared reflection absorption spectroscopy (IRRAS).16 Figure 4 shows IRRA-spectra from a CMP-membrane transferred to a gold wafer. Typical bands from the vibrations of the aromatic backbone are at 1,605 cm-1, 1,515 cm-1 and 1,412 cm-1. Unreacted alkyne and azide groups can be observed by characteristic bands at 2,125 cm-1 and 1,227 cm-1. Figure 5 shows a scanning electron microscopy (SEM...

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 ...

The overall goal of this procedure is to obtain freestanding nano membranes of conjugated microporous polymers. This method can help to answer key questions in the field of conjugated microporous polymers, such as how to prepare thin films and freestanding membranes of usually insoluble materials. The main advantage of this technique is that it allows the production and the transfer of uniform membranes with ultra low and homogeneous thickness by performing a step by synthesis on al substrate.Though this method can be applied for membrane separation, it can also be useful for other applications such as organic electronics or heterogeneous catalysis. Demonstrating the procedure will be yonic to line a technician from our lab. Prepare the apparatus for CMP fabrication.Use a 500 milliliter one neck round bottom flask and add 300 milliliters of tetra nitrofuran or THF. Put a prepared substrate coated with alpine terminated, self-assembled monolayer or SAM in the sample compartment, use a sample holder so that the substrate is standing upright. Connect the apparatus to the schleck line via the junction on top of the reflux cooler.Evacuate and ventilate the apparatus with inert gas three times. Then let THF out from the sample compartment over the outlet at the bottom of the sample compartment and close the outlet. Next, add one milliliter of a prepared TPM azi solution and 0.5 milliliters of a copper catalyst solution to the sample compartment via the screw cap with septum.Use a syringe with a hollow needle to transfer the solutions sequentially from the flank flask to the reaction apparatus. After waiting approximately 30 minutes, let out the reaction solution over the outlet at the bottom of the sample compartment. Close the outlet and collect the condensed THF for rinsing the sample.Wait approximately 30 minutes more, then let out the rinsing solution over the outlet at the bottom of the sample compartment and close the outlet. Give one milliliter of the prepared TPM Aine solution and 0.5 milliliters of the copper catalyst solution to the sample compartment via the screw cap with septum. Transfer the solution sequentially from thenk to the reaction apparatus using a syringe with a hollow needle.After waiting approximately 30 minutes, let out the reaction solution over the outlet at the bottom of the sample compartment. Close the outlet and collect the condensed THF for rinsing the sample. After waiting for an additional 30 minutes, repeat the sequential addition until the desired amount of layers is reached, one layer is approximately one nanometer thick.As a final step, take out the CMP coated mica substrate. Rinse it with THF and ethanol, and then dry it under a nitrogen stream. Set a spin coder to a ramp time of 10 seconds from zero to 4, 000 RPMA holding time of 40 seconds, and a ramp time of 10 seconds from 4, 000 to zero RPM.Place the CMP coated MICA substrate on the spin coder and put A-P-M-M-A solution on the wafer until it is completely covered. Start the spin coder, cut off one millimeter from each edge of the coated mica substrate using a scissor to cut the edges. Then fill a 150 milliliter crystallizing dish with an iodine potassium iodide solution and fill a 100 milliliter crystallizing dish with a potassium iodide solution.Put the PMMA coated CMP gold on the mica substrate with mica in contact with the solution on top of the iodine potassium iodide solution. Be careful that it does not sink. Wait at least five minutes, then transfer the PMMA coated CMP gold MICA substrate from the iodine potassium iodide solution to the top of the potassium iodide solution with MICA in contact with the solution.Once again, be careful that it does not sink and wait at least five minutes. Next, fill a 250 milliliter crystallizing dish with distilled water. Strip off the P-M-M-A-C-M-P gold film from the MICA by slightly immersing the substrate beginning from one edge in distilled water.Hold the substrate so that the MICA is pointing to the water dip coat the P-M-M-A-C-M-P gold on the silicon wafer by approaching the swimming P-M-M-A-C-M-P gold membrane. Slowly with the wafer until it touches the edge of the membrane, pull out the silicon wafer slowly. Once the silicon wafer is in contact with the P-M-M-A-C-M-P gold membrane, then strip the P-M-M-A-C-M-P gold film off of the silicon wafer by slightly immersing the substrate, beginning from one edge in the iodine potassium iodide solution, and waiting 15 minutes after the gold is completely etched.Transfer the P-M-M-A-C-M-P membrane to water via the silicon wafer and wait an additional 15 minutes. Repeat this step three times to wash the membrane with water. Then transfer the washed P-M-M-A-C-M-P membrane to a gold coated silicon wafer.As before, let the P-M-M-A-C-M-P substrate dry and air for at least two hours. To dissolve the PMMA. Put the P-M-M-A-C-M-P substrate in acetone and wait 30 minutes.Take out the substrate and rinse it with acetone. After repeating this step three times, let the CMP substrate dry for at least two hours. The membranes are characterized by infrared reflection, absorption spectroscopy or ir.RAS shown here is an IRRA spectrum from a CMP membrane transferred to a gold wafer. Typical bands from the vibrations of the aromatic backbone are at 1, 605 1, 515 and 1, 412 inverse centimeters. In case of residual unreactive, azide, or alkin groups characteristic bands at 2, 125 and 1, 227 inverse centimeters can be observed.Shown here is a scanning electron microscopy image. The freestanding membrane is clearly visible Once mastered, this transfer technique can be done in less than one hour if it is performed properly. While attempting this procedure, it's important to remember to cut the edges of the micro substrate after spin coating Following this procedure.Other methods like synthetic modification or photo patterning can be formed to optimize the purpose chemistry of the nan membrane for the desired applications After its development. This technique can help researchers in the field of congregated micro pros polymers to transfer the promising bulk properties into real devices.

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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.

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

A simple, reproducible, and versatile approach for the synthesis of intergrown, polycrystalline metal-organic framework membranes on a wide range of unmodified porous and non-porous supports is presented.

Electrophoretic Crystallization of Ultrathin High-performance Metal-organic Framework Membranes

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.

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

A protocol for the synthesis and characterization of self-assembled metal-organic framework monolayers is provided using polymer-grafted, metal-organic framework (MOF) crystals. The procedure shows that polymer-grafted MOF particles can be self-assembled at an air-water interface resulting in well-formed, free-standing, monolayer structures as evidenced by scanning electron microscopy imaging.

Synthesis and Characterization of Self-Assembled Metal-Organic Framework Monolayers Using Polymer-Coated Particles

Confocal microscopy is used to image quiescent and flowing colloid-polymer mixtures, which are studied as model systems for attractive suspensions. Image analysis algorithms are used to calculate structural and dynamic metrics for the colloidal particles that measure changes due to geometric confinement.

Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures

Learn layer-by-layer synthesis of freestanding conjugated microporous polymer nanomembranes using sacrificial substrates. This method enables uniform membrane production and transfer for membrane separation and organic electronics applications.

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

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