The authors have no acknowledgements.

1. Sintesi di CMP film sottili attraverso l&#39;aggiunta sequenziale <ol><li> Auto-assemblati monostrato (SAM) funzionalizzazione di oro su mica. <ol><li> Preparare la soluzione 1 mM di 11-thioacetyl-undecano acid-propargyl ammide 14 in etanolo (SAM-soluzione). Miscelare con bagno a ultrasuoni fino a soluzione è limpida. Proteggere la bottiglia dalla luce utilizzando un foglio di alluminio. </li><li> Ottenere l&#39;oro rivestite mica wafer sotto argon. Dopo il ritiro dal contenitore immergere il wafer mica direttamente alla SAM-soluzione per 18 ore. </li><li> Prendere il preparato Au-mica cialda fuori dalla SAM-soluzione, risciacquare con etanolo e secco sotto corrente di azoto. Successivamente memorizzare il substrato al riparo dalla luce e sotto gas inerte. </li></ol></li><li> Soluzioni Precursore. <ol><li> Pesare 18.64 mg di Cu-catalizzatore (Tetrakis (acetonitrile) rame (I) esafluoro-fosfato), 20,83 mg tetrafenilmetano (TPM) -alkyne e 24.22 mg TPM-azide e riempire ogni componente in un pallone Schlenk separata.Vedere la Figura 1 per TPM-alchino e TPM-azide, la sintesi è descritto in riferimento 15. Evacuare e riempire con gas inerte (N 2 o argon) 3 volte. </li><li> Aggiungere 25 ml di tetraidrofurano privo di acqua (THF) ad ogni pallone Schlenk. Proteggere i palloni con TPM-azide e TPM-alkyne dalla luce con un foglio di alluminio. </li></ol></li><li> Preparare apparecchi per la fabbricazione CMP. Nota: L&#39;apparato di sintesi è illustrato nella figura 2. <ol><li> Utilizzare un pallone a fondo tondo da 250 ml un collo. Compilare 130 ml THF. Mettere il substrato preparata rivestito con alkyne terminato SAM nel vano campione. Utilizzare un portacampioni, in modo che il substrato è in piedi. </li><li> Collegare l&#39;apparecchiatura alla linea schlenk tramite giunzione sopra il refrigerante a ricadere. </li><li> Evacuare e ventilare con gas inerte per 3 volte. </li></ol></li><li> Inoltre sequenziale in condizioni inerti. <ol><li> Impostare il riscaldamento a 90 ° C e aspettare che il THF è reflussaggio. </li><li> Lasciare fuori THF dal vano del campione sopra la presa sul fondo del vano campione. Chiudere la presa. </li><li> Dare 1 ml della soluzione TPM-azide preparati e 0,5 ml della soluzione di Cu (I) catalizzatore per il compartimento del campione attraverso il tappo a vite con setto. Utilizzare una siringa con un ago cavo per trasferire la soluzione in sequenza dal pallone Schlenk all&#39;apparecchio reazione. Nota: La sequenza non ha alcuna influenza alla reazione. </li><li> Attendere circa 30 minuti. </li><li> Lasciare la soluzione di reazione sopra la presa sul fondo del vano campione. Chiudere l&#39;uscita e raccogliere il THF condensata per il risciacquo del campione. Attendere circa 30 minuti. </li><li> Lasciare la soluzione di risciacquo sopra la presa sul fondo del vano campione. Chiudere la presa. </li><li> Dare 1 ml della soluzione TPM-alchino preparati e 0,5 ml della soluzione di Cu (I) catalizzatore per il compartimento del campione attraverso il tappo a vite con setto. Utilizzare una siringa con una cavitàago per trasferire la soluzione in sequenza dal pallone Schlenk all&#39;apparecchio reazione. Nota: La sequenza non ha alcuna influenza alla reazione. </li><li> Attendere circa 30 minuti. </li><li> Lasciare la soluzione di reazione sopra la presa sul fondo del vano campione. Chiudere l&#39;uscita e raccogliere il THF condensata per il risciacquo del campione. Attendere circa 30 minuti. </li><li> Ripetere i passaggi da 1.4.3 a 1.4.9 fino al raggiungimento della quantità desiderata di strati. Nota: Un uno spessore di circa 1 nm. </li><li> Estrarre il substrato di mica rivestite CMP, sciacquarlo con THF, etanolo e asciugare in corrente di azoto. </li></ol></li></ol> 2. Trasferimento di CMP nanomembrane <ol><li> Soluzione di poli (metilmetacrilato) (PMMA). <ol><li> Preparare una soluzione di 4% (in peso) PMMA (M 996 kDa) in acetato di etile. Sciogliere il PMMA utilizza bagno a ultrasuoni fino alla soluzione è limpida. </li></ol></li><li> Spin coating di soluzione PMMA. <ol><li> Impostare il dispositivo a induzione di rotazione a Ratempo mp 10 secondi da 0 a 4.000 giri, tempo di mantenimento 40 sec e il tempo di rampa 10 secondi da 4.000 a 0 rpm. </li><li> Posizionare il CMP substrato di mica rivestito sulla coater rotazione e mettere la soluzione PMMA sul wafer finchè è completamente coperto. Avviare il dispositivo a induzione di rotazione. </li><li> Dopo spin coating è completato, mettere il campione per 5 minuti su una piastra riscaldante a 90 ° C. </li><li> Tagliare 1 mm da ogni bordo del substrato mica rivestita. Utilizzare una forbice per tagliare i bordi. </li></ol></li><li> Trasferimento di PMMA rivestito CMP nanomembrana. <ol><li> Preparare la soluzione di I 2 / KI / H 2 O (1: 4: 40 m / m / m) e KI / H 2 O (1:10 m / m). </li><li> Riempire la soluzione che ho 2 / KI H 2 O in 150 ml cristallizzazione piatto e riempire la soluzione KI / H 2 O in 100 ml di cristallizzazione piatto. Mettere l&#39;oro CMP PMMA rivestiti su substrato di mica, mica in contatto soluzione, in cima alla I 2 / KI / H 2 O soluzione. Fate attenzione che non affonda.Attendere almeno 5 minuti. </li><li> Mettere il CMP oro substrato di mica rivestite PMMA dalla I 2 / KI / H 2 O soluzione sopra della soluzione KI / H 2 O, con mica in contatto soluzione. Fate attenzione che non affonda. Attendere almeno 5 minuti. </li><li> Riempire acqua distillata in 250 ml cristallizzazione piatto. Togliere il / pellicola / oro CMP PMMA dal mica. A tale scopo, leggermente immergendo il substrato, a partire da un bordo, in acqua distillata. Tenere il substrato in modo che la mica punta all&#39;acqua. Nota: La procedura è illustrata nella figura 3. </li><li> Dip-coat PMMA / CMP / oro sul wafer di silicio. A tale scopo, si avvicina il PMMA / CMP / oro lentamente con la cialda fino a toccare bordo della piscina PMMA / membrana / oro CMP. Estrarre il wafer di silicio lentamente, una volta che il Si-wafer è in contatto con il / CMP membrana PMMA / oro. </li><li> Striscia la / CMP pellicola PMMA / oro fuori dal wafer di silicio. A tale scopo, un po &#39;immergendo il substrato, a cominciare da una cura dige, in I 2 / KI / H 2 O soluzione. Aspettare 15 minuti. </li><li> Dopo l&#39;oro è completamente inciso, trasferire la membrana PMMA / CMP di acqua attraverso il wafer di silicio. Aspettare 15 minuti. </li><li> Ripetere il punto 2.3.7 tre volte per lavare la membrana con acqua. </li><li> Trasferire la membrana PMMA / CMP lavato al substrato desiderato, ad esempio, un vetrino o un oro rivestite wafer di silicio, tramite il metodo indicato nel passaggio 2.3.5. Lasciate che il PMMA / CMP supporto asciutto in aria per almeno 2 ore. </li></ol></li><li> Scioglimento del PMMA. <ol><li> Mettere il substrato PMMA / CMP in acetone. Attendere 30 min. Estrarre il substrato e risciacquare con acetone. </li><li> Ripetere il punto 2.4.1 tre volte. </li><li> Lasciate che il CMP supporto asciutto per almeno 2 ore. </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.

Per la sintesi del CMP film la soluzione del catalizzatore deve essere fresco. Un catalizzatore rotto (cioè, ossidato) è indicato da una colorazione blu della soluzione. La soluzione fresca è incolore. Un punto cruciale è per tagliare i bordi del substrato di mica dopo spin coating PMMA. Anche difetti del substrato deve essere tagliato, cioè, ogni punto fosse il PMMA può venire in contatto con il substrato di mica, a causa di uno strato di oro mancante. Altrimenti lo ...

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 come grandi materiali Superficie hanno suscitato crescente interesse recente, a causa della loro elevata variabilità nella incorporazione di gruppi funzionali in combinazione con loro eccezionale stabilità termica e chimica e basse densità. Tuttavia, la loro natura insolubile causa problemi nella loro lavorazione poiché le tecniche normalmente applicate come rivestimento a rotazione non sono disponibili. Specialmente per le applicazioni di membrana, in cui il trattamento di CMP come film sottili è desiderabile, i problemi di elaborazione hanno ostacolato la loro applicazione commerciale. Qui si descrive la sintesi interfacciale di film sottili su substrati funzionalizzati CMP tramite layer-by-layer (LBL) sintesi molecolare. Questo processo consente di ottenere film con spessore desiderato e composizione e gradienti di composizione persino desiderati. L&#39;uso di supporti sacrificali permette la preparazione di membrane autoportanti mediante dissoluzione del supporto dopola sintesi. Per gestire tali membrane autoportanti ultrasottili di protezione con rivestimenti sacrificali ha mostrato grande promessa, per evitare la rottura delle nanomembrane. Per trasferire i nanomembrane al substrato desiderato, le membrane sono rivestite upfloated all&#39;interfaccia aria-liquido e quindi trasferiti tramite dip coating.

Le membrane sono caratterizzati mediante spettroscopia di assorbimento infrarosso riflessione (IRRAS). 16 Figura 4 mostra IRRA-spettri da un CMP-membrana trasferito ad un wafer oro. Bande tipiche vibrazioni della dorsale aromatico sono a 1,605 cm -1, 1.515 cm -1 e 1.412 cm -1. Reagiti gruppi alchini e azide può essere osservato da bande caratteristici a 2.125 cm -1 e 1.227 cm -1. La Figura 5 mostra una i...

Watch this Scientific Journal Video about Layer-by-layer Synthesis and Transfer of Freestanding Conjugated Microporous Polymer Nanomembranes at JoVE.com

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.

Sintesi layer-by-layer e di trasferimento delle Freestanding coniugati microporosi Polymer nanomembrane

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 Views.  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.

Video: 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.

Verso Biomimicking Legno: Fabbricato Free-standing Films di Nanocellulose, lignina, e policatione sintetico

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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Chimica

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.

Una tecnica di funzionalizzare e Self-montare macroscopiche nanoparticelle-ligando monostrato Films su substrati privi di modello

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.

Fabbricazione di ampia superficie Free-standing ultrasottili film polimerici

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.

Fabbricazione dei canali termoplastico Microfluidic

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.

Formazione di microarray di membrana con un metodo di assemblaggio con sede a seccatoio

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

Bioingegneria

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.

Preparazione di membrane Light-responsive da un innesto superficie combinata e Postmodifica processo

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.

Fabbricazione di superfici reattive con spazzola e film reticolato di co-polimeri funzionalizzati Azlactone blocco

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

Ingegneria

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.

Elettroforetica cristallizzazione delle membrane ultrasottile ad alte prestazioni Metal-organic frameworks

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.

Procedura per il trasferimento di pellicole polimeriche su substrati porous con difetti ridotti al minimo

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>Visualizzazione microscopica di nanografeni porosi sintetizzati attraverso una combinazione di soluzione e chimica superficiale

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.