The authors have no acknowledgements.

1. Síntese do CMP Filmes Finos através de adição sequencial <ol><li> Auto-montado monocamada (SAM) funcionalização de ouro em mica. <ol><li> Preparar a solução de 11 mM de 1-tioacetil-undecano amida do ácido 14-propargil em etanol (SAM-solução). Misture com banho ultra-sônico até solução é clara. Proteger a garrafa de luz usando papel alumínio. </li><li> Obter revestido de ouro mica wafer sob árgon. Após a retirada do recipiente de armazenamento de mergulhar a bolacha mica directamente à SAM-solução durante 18 h. </li><li> Leve o preparado wafer Au-mica fora da solução-SAM, lavar com álcool etílico e seco sob corrente de azoto. Depois armazenar o substrato protegido da luz e sob um gás inerte. </li></ol></li><li> Soluções de precursor. <ol><li> Pesar 18,64 mg de Cu-catalisador (tetraquis (acetonitrilo) cobre (I), hexafluoro-fosfato), 20,83 mg tetraphenylmethane (TPM) e 24,22 mg -alkyne TPM-azida e encher cada componente para um balão de Schlenk separado.Ver Figura 1 para TPM-alcino e TPM-azida, a síntese é descrita na referência 15. Evacuar e encher com gás inerte (N2 ou árgon) 3 vezes. </li><li> Adicionar 25 ml de tetra-livre de água (THF) a cada balão Schlenk. Proteger os frascos com TPM-azida e TPM-alcino de luz usando papel alumínio. </li></ol></li><li> Preparar um aparelho para a fabricação de CMP. Nota: O aparelho de síntese é mostrado na Figura 2. <ol><li> Usar um balão de fundo redondo de 250 ml de uma tubuladura. Preencha 130 ml THF. Coloque o substrato preparado revestido com alcino encerrado SAM no compartimento de amostra. Usar um suporte de amostras, de modo que o substrato é colocado na posição vertical. </li><li> Ligar o aparelho para a linha de Schlenk por meio da junção no topo do refrigerador de refluxo. </li><li> Evacuar e ventilar com gás inerte 3 vezes. </li></ol></li><li> Adição sequencial sob condições inertes. <ol><li> Definir o aquecedor para 90 ° C e esperar até o THF é refluxing. </li><li> Deixe para fora do compartimento de THF a amostra através da saída no fundo do compartimento da amostra. Fechar a saída. </li><li> Dar origem a 1 ml da solução de TPM-azida preparada e 0,5 ml da solução de Cu (I) catalisador para o compartimento da amostra através da tampa roscada com septo. Utilize uma seringa com uma agulha oca para transferir a soluções sequencialmente a partir do balão de Schlenk com o aparelho de reacção. Nota: A sequência não tem qualquer influência para a reacção. </li><li> Espere cerca de 30 min. </li><li> Deixe a solução de reacção através da saída no fundo do compartimento da amostra. Fechar a saída e recolhe-se o THF condensado para enxaguar a amostra. Espere cerca de 30 min. </li><li> Deixe a solução de lavagem através da saída no fundo do compartimento da amostra. Fechar a saída. </li><li> Dar origem a 1 ml da solução de TPM-alcino preparada e 0,5 ml de solução de Cu (I) catalisador para o compartimento da amostra através da tampa roscada com septo. Use uma seringa com uma cavidadeagulha, para transferir a solução sequencialmente a partir do balão de Schlenk com o aparelho de reacção. Nota: A sequência não tem qualquer influência para a reacção. </li><li> Espere cerca de 30 min. </li><li> Deixe a solução de reacção através da saída no fundo do compartimento da amostra. Fechar a saída e recolhe-se o THF condensado para enxaguar a amostra. Espere cerca de 30 min. </li><li> Repita os passos 1.4.3 a 1.4.9 até que a quantidade desejada de camadas é atingido. Nota: Uma camada é de aproximadamente 1 nm de espessura. </li><li> Retire o substrato mica CMP-revestido, lave-o com THF, etanol e secá-la sob uma corrente de azoto. </li></ol></li></ol> 2. Transferência de CMP Nanomembranes <ol><li> Solução de poli (metacrilato de metilo) (PMMA). <ol><li> Prepara-se uma solução de 4% (em peso) de PMMA (M 996 kDa) em acetato de etilo. Dissolve-se o PMMA com banho de ultrassons, até a solução se torne clara. </li></ol></li><li> Revestimento por centrifugação de uma solução de PMMA. <ol><li> Defina o coater rotação à ARmp tempo de 10 segundos de 0 a 4.000 rpm, segurando tempo de 40 seg e 10 seg tempo de rampa de 4.000 a 0 rpm. </li><li> Coloque o substrato mica revestida CMP no coater rotação e colocar a solução PMMA na bolacha até que esteja completamente coberto. Comece o revestidor de rotação. </li><li> Depois de revestimento por rotação é completado, colocar a amostra durante 5 minutos numa placa de aquecimento a 90 ° C. </li><li> Cortar 1 mm a partir de cada orla do substrato revestido de mica. Utilize uma tesoura para cortar as bordas. </li></ol></li><li> Transferência de PMMA revestido CMP nanomembrane. <ol><li> Preparar a solução de I2 / KI / H2O (1: 4: 40 m / m / m) e de Kl / H 2 O (1:10 m / m). </li><li> Encha a solução I 2 / KI H 2 O em 150 ml de cristalização prato e preencha a solução KI / H 2 O em 100 ml de cristalização prato. Coloque o ouro revestido CMP PMMA em substrato de mica, mica em contacto com a solução, no topo do I2 / KI / H2O solução. Tenha cuidado para que ele não afundar.Espere pelo menos 5 min. </li><li> Colocar o substrato de mica revestida de ouro CMP PMMA do I2 / KI / H2O solução no topo da solução de KI / H2O, com a mica em contacto a solução. Tenha cuidado para que ele não afundar. Espere pelo menos 5 min. </li><li> Preencha água destilada em 250 ml de cristalização prato. Tire o CMP / filme / ouro PMMA da mica. Faça isso por um pouco imersão do substrato, a partir de uma ponta, em água destilada. Segurar o substrato, de modo que a mica está a apontar para a água. Nota: O procedimento é mostrado na Figura 3. </li><li> Dip-coat a PMMA / CMP / ouro no wafer de silício. Para fazer isso, se aproximando do PMMA / CMP / ouro lentamente com a bolacha até tocar borda da natação PMMA / CMP membrana / ouro. Puxe o wafer de silício lentamente, uma vez que o Si-wafer está em contato com o CMP / membrana PMMA / ouro. </li><li> Tira o CMP / filme PMMA / ouro fora do wafer de silício. Faça isso por um pouco imersão do substrato, a partir de uma edGE, no I 2 / KI / H2O solução. Espere 15 min. </li><li> Depois de o ouro é completamente gravado, transferir a membrana de PMMA / CMP à água através da bolacha de silício. Espere 15 min. </li><li> Repetir o passo 2.3.7 três vezes para lavar a membrana com água. </li><li> Transferir a membrana de PMMA / CMP lavadas com o substrato desejado, por exemplo, uma lâmina de microscópio ou uma placa de silício revestido de ouro, por meio do método mencionado no passo 2.3.5. Deixe o substrato seco PMMA / CMP em ar durante pelo menos 2 horas. </li></ol></li><li> A dissolução do PMMA. <ol><li> Colocar o substrato de PMMA / CMP em acetona. Espere 30 min. Retire o substrato e lave-o com acetona. </li><li> Repita o passo 2.4.1 três vezes. </li><li> Deixe o substrato seco CMP durante pelo menos 2 horas. </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>
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<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>
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</ol>

The authors have nothing to disclose.

Para a síntese de a-CMP filme a solução do catalisador tem que ser fresca. Um catalisador quebrada (isto é, oxidado) é indicada por uma coloração azul da solução. A nova solução é incolor. Um ponto crucial é cortar as bordas do substrato de mica após revestimento por centrifugação de PMMA. Também defeitos no substrato deve ser cortado, ou seja, cada local foram o PMMA pode entrar em contacto com o substrato de mica, por causa de uma camada de ouro em falta....

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

CMP como materiais de grandes dimensões da área de superfície tem atraído um interesse crescente, recentemente, devido à sua elevada variabilidade na incorporação de grupos funcionais em combinação com a sua excelente estabilidade térmica e química, e baixas densidades. No entanto, a sua natureza insolúvel causa problemas no seu processamento desde técnicas geralmente aplicadas, tais como revestimento por rotação não estão disponíveis. Especialmente para aplicações de membrana, onde o processamento da CMP como filmes finos é desejável, os problemas de processamento têm impedido a sua aplicação comercial. Aqui nós descrevemos a síntese interfacial da CMP filmes finos sobre substratos funcionalizados via (LBL) síntese molecular camada por camada. Este processo permite a preparação de películas com a espessura desejada e da composição e gradientes de composição ainda desejados. A utilização de suportes sacrificiais permite a preparação de membranas autoportante por dissolução do suporte depoisa síntese. Para lidar com tais membranas autônomas ultra-finas da protecção com revestimentos de sacrifício mostrou uma grande promessa, para evitar a ruptura dos nanomembranes. Para transferir os nanomembranes ao substrato desejado, as membranas revestidas são upfloated na interface ar-líquido e, em seguida, transferidos por meio de revestimento por imersão.

As membranas são caracterizadas por espectroscopia de absorção de infravermelho de reflexão (IRRAS). 16 A Figura 4 mostra-IRRA espectros a partir de uma membrana de CMP-transferido para uma bolacha de ouro. Faixas típicas a partir das vibrações da espinha dorsal aromático são a 1.605 cm-1, 1515 cm-1 e 1.412 cm-1. Grupos alcino e azida que não reagiram podem ser observados por bandas características em 2125 cm-1 e 1227 cm-1. <st...

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

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.

Síntese camada por camada e Transferência de autônomos conjugados microporosas 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 ...

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9.3K visualizações.  Karlsruhe Institute of Technology. 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.

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

Towards Biomimicking Wood: Fabricated Free-standing Films of Nanocellulose, Lignin, and a Synthetic Polycation

Woody materials are comprised of plant cell walls that contain a layered secondary cell wall composed of structural polymers of polysaccharides and lignin. Layer-by-layer (LbL) assembly process which relies on the assembly of oppositely charged molecules from aqueous solutions was used to build a freestanding composite film of isolated wood polymers of lignin and oxidized nanofibril cellulose (NFC). To facilitate the assembly of these negatively charged polymers, a positively charged polyelectrolyte, poly(diallyldimethylammomium chloride) (PDDA), was used as a linking layer to create this simplified model cell wall. The layered adsorption process was studied quantitatively using quartz crystal microbalance with dissipation monitoring (QCM-D) and ellipsometry. The results showed that layer mass/thickness per adsorbed layer increased as a function of total number of layers. The surface coverage of the adsorbed layers was studied with atomic force microscopy (AFM). Complete coverage of the surface with lignin in all the deposition cycles was found for the system, however, surface coverage by NFC increased with the number of layers. The adsorption process was carried out for 250 cycles (500 bilayers) on a cellulose acetate (CA) substrate. Transparent free-standing LBL assembled nanocomposite films were obtained when the CA substrate was later dissolved in acetone. Scanning electron microscopy (SEM) of the fractured cross-sections showed a lamellar structure, and the thickness per adsorption cycle (PDDA-Lignin-PDDA-NC) was estimated to be 17 nm for two different lignin types used in the study. The data indicates a film with highly controlled architecture where nanocellulose and lignin are spatially deposited on the nanoscale (a polymer-polymer nanocomposites), similar to what is observed in the native cell wall.

The objective of this research was to form synthetic plant cell wall tissue using layer-by-layer assembly of nanocellulose fibrils and isolated lignin assembled from dilute aqueous suspensions.&#160; Surface measurement techniques of quartz crystal microbalance and atomic force microscopy were used to monitor the formation of the polymer-polymer nanocomposite material.

Rumo Biomimicking Madeira: Fabricados free-standing Filmes de nanocellulose, lignina, e uma policátion sintético

Woody materials are comprised of plant cell walls that contain a layered secondary cell wall composed of structural polymers of polysaccharides and ...

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A Technique to Functionalize and Self-assemble Macroscopic Nanoparticle-ligand Monolayer Films onto Template-free Substrates

This protocol describes a self-assembly technique to create macroscopic monolayer films composed of ligand-coated nanoparticles1,2. The simple, robust and scalable technique efficiently functionalizes metallic nanoparticles with thiol-ligands in a miscible water/organic solvent mixture allowing for rapid grafting of thiol groups onto the gold nanoparticle surface. The hydrophobic ligands on the nanoparticles then quickly phase separate the nanoparticles from the aqueous based suspension and confine them to the air-fluid interface. This drives the ligand-capped nanoparticles to form monolayer domains at the air-fluid interface.&#160; The use of water-miscible organic solvents is important as it enables the transport of the nanoparticles from the interface onto template-free substrates.&#160; The flow is mediated by a surface tension gradient3,4 and creates macroscopic, high-density, monolayer nanoparticle-ligand films.&#160; This self-assembly technique may be generalized to include the use of particles of different compositions, size, and shape and may lead to an efficient assembly method to produce low-cost, macroscopic, high-density, monolayer nanoparticle films for wide-spread applications.

A simple, robust and scalable technique to functionalize and self-assemble macroscopic nanoparticle-ligand monolayer films onto template-free substrates is described in this protocol.

Uma técnica para funcionalizar e auto-montar macroscópicas Nanopartículas-ligante monocamada Films em substratos sem Modelo

This protocol describes a self-assembly technique to create macroscopic monolayer films composed of ligand-coated nanoparticles1,2. The simple, robust and ...

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.

Fabricação de grande-área royalty-pé ultrafinos Polymer Films

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

Fabrication of the Thermoplastic Microfluidic Channels

In our lab, we have successfully isolated nucleic acids directly from microliter and submicroliter volumes of human blood, urine and stool using polymer/nanoparticle composite microscale lysis and solid phase extraction columns. The recovered samples are concentrated, small volume samples that are PCRable, without any additional cleanup. Here, we demonstrate how to fabricate thermoplastic microfluidic chips using hot embossing and heat sealing. Then, we demonstrate how to use in situ light directed surface grafting and polymerization through the sealed chip to form the composite solid phase columns. We demonstrate grafting and polymerization of a carbon nanotube/polymer composite column for bacterial cell lysis. We then show the lysis process followed by solid phase extraction of nucleic acids from the sample on chip using a silica/polymer composite column. The attached protocols contain detailed instructions on how to make both lysis and solid phase extraction columns.

Here we demonstrate how to fabricate thermoplastic microfluidic chips using hot embossing and heat sealing. Then we demonstrate how to use in situ light directed surface grafting and polymerization through the sealed chip to form the composite solid phase columns.

Fabricação dos canais microfluídicos Termoplásticos

In our lab, we have successfully isolated nucleic acids directly from microliter and submicroliter volumes of human blood, urine and stool using ...

Biologia

Formation of Biomembrane Microarrays with a Squeegee-based Assembly Method

Lipid bilayer membranes form the plasma membranes of cells and define the boundaries of subcellular organelles. In nature, these membranes are heterogeneous mixtures of many types of lipids, contain membrane-bound proteins and are decorated with carbohydrates. In some experiments, it is desirable to decouple the biophysical or biochemical properties of the lipid bilayer from those of the natural membrane. Such cases call for the use of model systems such as giant vesicles, liposomes or supported lipid bilayers (SLBs). Arrays of SLBs are particularly attractive for sensing applications and mimicking cell-cell interactions. Here we describe a new method for forming SLB arrays. Submicron-diameter SiO2 beads are first coated with lipid bilayers to form spherical SLBs (SSLBs). The beads are then deposited into an array of micro-fabricated submicron-diameter microwells. The preparation technique uses a "squeegee" to clean the substrate surface, while leaving behind SSLBs that have settled into microwells. This method requires no chemical modification of the microwell substrate, nor any particular targeting ligands on the SSLB. Microwells are occupied by single beads because the well diameter is tuned to be just larger than the bead diameter. Typically, more 75% of the wells are occupied, while the rest remain empty. In buffer SSLB arrays display long-term stability of greater than one week. Multiple types of SSLBs can be placed in a single array by serial deposition, and the arrays can be used for sensing, which we demonstrate by characterizing the interaction of cholera toxin with ganglioside GM1. We also show that phospholipid vesicles without the bead supports and biomembranes from cellular sources can be arrayed with the same method and cell-specific membrane lipids can be identified.

Supported lipid bilayers and natural membrane particles are convenient systems that can approximate the properties of cell membranes and be incorporated in a variety of analytical strategies. Here we demonstrate a method for preparing microarrays composed of supported lipid bilayer-coated SiO2 beads, phospholipid vesicles or natural membrane particles.

Formação de biomembrana Microarrays com um método de montagem baseada em Rodo

Lipid bilayer membranes form the plasma membranes of cells and define the boundaries of subcellular organelles. In nature, these membranes are ...

Bioengenharia

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.

Preparação de Membranas de Luz respondem por um enxerto de superfície combinada e Processo Postmodification

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

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.

Fabricação de superfícies reativas com escova, como filmes de quitosana de polímeros co bloco Azlactone-acrescida e

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

Engenharia

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

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and non-porous supports (polymer, ceramic, metal, carbon, and graphene). We developed a novel crystallization technique, which is termed the ENACT approach: the electrophoretic nuclei assembly for the crystallization of highly intergrown thin films (ENACT). This approach allows for a high density of heterogeneous nucleation of MOFs on a chosen substrate via the electrophoretic deposition (EPD) directly from the precursor sol. The growth of well-packed MOF nuclei leads to a highly intergrown polycrystalline MOF film. We show that this simple approach can be used for the synthesis of thin, intergrown zeolite imidazole framework (ZIF)-7 and ZIF-8 films. The resulting 500 nm-thick ZIF-8 membranes show a considerably high H2 permeance (8.3 x 10-6 mol m-2 s-1 Pa-1) and ideal gas selectivities (7.3 for H2/CO2, 15.5 for H2/N2, 16.2 for H2/CH4, and 2655 for H2/C3H8). An attractive performance for C3H6/C3H8 separation is also achieved (a C3H6 permeance of 9.9 x 10-8 mol m-2 s-1 Pa-1 and a C3H6/C3H8 ideal selectivity of 31.6 at 25 &#176;C). Overall, the ENACT process, owing to its simplicity, can be extended to synthesize intergrown thin films of a wide range of nanoporous crystalline materials.

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.

Eletroforética cristalização das membranas ultrafinos estrutura Metal-orgânicos de alto desempenho

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and ...

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.

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.

Procedimento para transferência de películas de polímero para substratos porosos com defeitos minimizados

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

Microscopic Visualization of Porous Nanographenes Synthesized through a Combination of Solution and On-Surface Chemistry

On-surface synthesis has recently been regarded as a promising approach for the generation of new molecular structures. It has been particularly successful in the synthesis of graphene nanoribbons, nanographenes and intrinsically reactive and instable, yet attractive species. It is based on the combination of solution chemistry aimed at preparation of appropriate molecular precursors for further ultra-high vacuum surface assisted transformations. This approach also owes its success to an incredible development of characterization techniques, such as scanning tunneling/atomic force microscopy and related methods, which allow detailed, local characterization at atomic scale. While the surface-assisted synthesis can provide molecular nanostructures with outstanding precision, down to single atoms, it suffers from basing on metallic surfaces and often limited yield. Therefore, the extension of the approach away from metals and the struggle to increase productivity seem to be significant challenges toward wider applications. Herein, we demonstrate the on-surface synthesis approach for generation of non-planar nanographenes, which are synthesized through a combination of solution chemistry and sequential surface-assisted processes, together with the detailed characterization by scanning probe microscopy methods.

<meta charset="utf8"></head><body>Visualização microscópica de nanografenos porosos sintetizados através de uma combinação de solução e química na superfície

A combination of solution and surface assisted synthesis opens new directions in the atomically precise synthesis of nanostructures. Scanning tunneling microscopy (STM) supplemented by non-contact atomic force microscopy (nc-AFM) enables detailed characterization of newly designed and generated carbon-based nano-objects.