The authors have no acknowledgements.

1. Synthese von CMP Thin Films durch sequentielle Zugabe <ol><li> Selbstorganisierten Monoschicht (SAM) Funktionalisierung von Gold auf Glimmer. <ol><li> Bereiten 1 mM Lösung von 11-Thioacetyl-undecan säure Propargyl Amid 14 in Ethanol (SAM-Lösung). Mischen Sie mit Ultraschallbad, bis die Lösung klar ist. Schützen Sie die Flasche aus Licht mit Aluminiumfolie. </li><li> Erhalten Gold beschichtete Glimmer Wafer unter Argon. Nach dem Herausziehen aus dem Vorratsbehälter eintauchen Glimmer Wafer direkt an die SAM-Lösung für 18 Std. </li><li> Nehmen Sie die vorbereiteten Au-Glimmer-Wafer aus der SAM-Lösung gründlich mit Ethanol und trocken unter einem Stickstoffstrom. Danach speichern Sie das Substrat vor Licht und unter Schutzgas geschützt. </li></ol></li><li> Vorläuferlösungen. <ol><li> Wiegen 18,64 mg Cu-Katalysator (Tetrakis (Acetonitril) Kupfer (I) Hexafluor-Phosphat), 20,83 mg Tetraphenylmethan (TPM) -Alkin und 24.22 mg TPM-Azid und füllen Sie jede Komponente in eine separate Schlenk-Kolben.Siehe Abbildung 1 für die TPM-Alkin und TPM-Azid wird die Synthese in Referenz 15 beschrieben. Evakuieren und füllen mit Inertgas (N 2 oder Argon) 3-mal. </li><li> 25 ml wasserfreies Tetrahydrofuran (THF) zu jedem Schlenkkolben. Schützen Sie die Flaschen mit TPM-Azid und TPM-Alkin von Licht mit Aluminiumfolie. </li></ol></li><li> Bereiten Vorrichtung zum CMP Fertigung. Anmerkung: Die Synthese Vorrichtung ist in Abbildung 2 dargestellt. <ol><li> Verwenden Sie einen 250-ml-Rundkolben. Füllen Sie 130 ml THF. Legen Sie den vorbereiteten Untergrund mit Alkin beschichtet beendet SAM im Probenraum. Verwenden einen Probenhalter, so daß das Substrat senkrecht steht. </li><li> Das Gerät wird an den Schlenk-Leitung über der Kreuzung auf der Oberseite der Rückflusskühler. </li><li> Evakuieren und belüften mit Inertgas 3 mal. </li></ol></li><li> Sequentielle Zugabe unter inerten Bedingungen. <ol><li> Stellen Sie die Heizung auf 90 ° C und warten Sie, bis das THF WiederFluss. </li><li> Stieß THF aus der Probenkammer über den Auslass am Boden des Probenbehältnisses. Schließen Sie die Steckdose. </li><li> Gib 1 ml der hergestellten TPM-Azid-Lösung und 0,5 ml der Cu (I) Katalysatorlösung zu der Probenkammer über den Schraubdeckel mit Septum. Verwenden Sie eine Spritze mit einer Hohlnadel, um die Lösungen der Reihe nach von der Schlenkkolben in die Reaktionsvorrichtung zu übertragen. Hinweis: Die Reihenfolge keinen Einfluss auf die Reaktion hat. </li><li> Warten Sie ca. 30 min. </li><li> Ließ sich die Reaktionslösung über den Auslass am Boden des Probenbehältnisses. Schließen Sie die Steckdose und sammeln die kondensierte THF zur Spülung der Probe. Warten Sie ca. 30 min. </li><li> Lassen sich die Spüllösung über den Auslass am Boden des Probenbehältnisses. Schließen Sie die Steckdose. </li><li> Gib 1 ml der hergestellten TPM-Alkin-Lösung und 0,5 ml der Cu (I) Katalysatorlösung zu der Probenkammer über den Schraubdeckel mit Septum. Verwenden Sie eine Spritze mit einer HohlNadel, um die Lösungen der Reihe nach von der Schlenkkolben in die Reaktionsvorrichtung zu übertragen. Hinweis: Die Reihenfolge keinen Einfluss auf die Reaktion hat. </li><li> Warten Sie ca. 30 min. </li><li> Ließ sich die Reaktionslösung über den Auslass am Boden des Probenbehältnisses. Schließen Sie die Steckdose und sammeln die kondensierte THF zur Spülung der Probe. Warten Sie ca. 30 min. </li><li> Die Schritte 1.4.3 bis 1.4.9, bis die gewünschte Menge an Schichten erreicht ist. Hinweis: Eine Schicht ist etwa 1 nm dick. </li><li> Nehmen Sie die CMP-beschichteten Glimmersubstrat, spülen Sie ihn mit THF, Ethanol und trocknen Sie es unter einem Stickstoffstrom. </li></ol></li></ol> 2. Transfer von CMP Nanomembranen <ol><li> Poly (methylmethacrylat) (PMMA) Lösung. <ol><li> Es wird eine Lösung von 4% (Gewicht) PMMA (M 996 kDa) in Ethylacetat. Man löst das PMMA mit Ultraschallbad, bis die Lösung klar ist. </li></ol></li><li> Aufschleudern PMMA-Lösung. <ol><li> Stellen Sie die Schleuderbeschichtungsvorrichtung auf Ramp Zeit 10 sec von 0 bis 4.000 min, Haltezeit 40 sec und Rampenzeit 10 s von 4000 bis 0 min. </li><li> Legen Sie die CMP beschichtete Glimmersubstrat auf dem Spin-Coater und legte die PMMA-Lösung auf dem Wafer, bis es vollständig bedeckt ist. Starten Sie den Spin-Coater. </li><li> Nach der Schleuderbeschichtung abgeschlossen ist, legen Sie die Probe für 5 min auf einer Heizplatte bei 90 ° C. </li><li> Abgeschnitten 1 mm von jeder Kante des beschichteten Glimmersubstrat. Verwenden Sie eine Schere, um die Kanten zu schneiden. </li></ol></li><li> Transfer von PMMA beschichtet CMP Nanomembran. <ol><li> Vorzubereiten Lösung von I 2 / KI / H 2 O (1: 4: 40 m / m / m) und der KI / H 2 O (1:10 m / m). </li><li> Füllen Sie den I 2 / KI H 2 O-Lösung in einem 150 ml Kristallisierschale und füllen Sie die KI / H 2 O-Lösung in einen 100-ml Kristallisierschale. Legen Sie die PMMA beschichtet CMP Gold auf Glimmer-Substrat, mit Glimmer in Kontakt zu Lösung, auf der Oberseite des I 2 / KI / H 2 O-Lösung. Seien Sie vorsichtig, dass sie nicht sinken.Warten Sie mindestens 5 min. </li><li> Legen Sie die PMMA beschichtet CMP gold Glimmer-Substrat von der I 2 / KI / H 2 O-Lösung auf der Oberseite des KI / H 2 O-Lösung, mit Glimmer in Kontakt zu Lösung. Seien Sie vorsichtig, dass sie nicht sinken. Warten Sie mindestens 5 min. </li><li> Füllen Sie destilliertes Wasser in einem 250 ml Kristallisierschale. Isolieren Sie die PMMA / CMP / Goldfolie von der Glimmer. Tun Sie dies durch leichtes Eintauchen des Substrats, beginnend von einer Kante, in destilliertem Wasser. Halten des Substrats, so daß der Glimmer wird dem Wasser zeigt. Anmerkung: Das Verfahren ist in Abbildung 3 dargestellt. </li><li> Tauchbeschichtung der PMMA / CMP / Gold auf dem Siliciumwafer. Tun Sie dies durch Annäherung an die PMMA / CMP / gold langsam mit dem Wafer, bis er Rand des Schwimm PMMA / CMP / gold Membran berührt. Langsam Ziehen des Silizium-Wafers, nachdem der Si-Wafer wird in Kontakt mit der PMMA / CMP / Goldmembran. </li><li> Isolieren Sie das PMMA / CMP / Goldfilm von der Silizium-Wafer. Tun Sie dies durch leichtes Eintauchen des Substrats, beginnend von einem edge, in der I 2 / KI / H 2 O Lösung. Warten Sie 15 min. </li><li> Nachdem das Gold vollständig geätzt, übertragen Sie die PMMA / CMP-Membran, um Wasser über die Silizium-Wafer. Warten Sie 15 min. </li><li> Wiederholen Sie Schritt 2.3.7 dreimal, um die Membran mit Wasser zu waschen. </li><li> Übertragen des gewaschenen PMMA / CMP-Membran auf das gewünschte Substrat, beispielsweise einen Objektträger oder eine mit Gold beschichtete Siliziumwafer über den im Schritt 2.3.5 beschriebenen Verfahren. Lassen Sie das PMMA / CMP-Substrat an der Luft trocknen für mindestens 2 Std. </li></ol></li><li> Auflösen von PMMA. <ol><li> Setzen Sie das PMMA / CMP-Substrat in Aceton. Warten Sie 30 min. Nehmen Sie das Substrat und spülen Sie ihn mit Aceton. </li><li> Wiederholen Sie Schritt 2.4.1 dreimal. </li><li> Lassen Sie die CMP Substrat trocken für mindestens 2 Std. </li></ol></li></ol>

<ol>
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A., W&#246;ll, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth+Mechanism+of+Metal&#8211;Organic+Frameworks:+Insights+into+the+Nucleation+by+Employing+a+Step-by-Step+Route.">Growth Mechanism of Metal&#8211;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. 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I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=in+Functional+Metal-Organic+Frameworks:+Gas+Storage,+Separation+and+Catalysis.">in Functional Metal-Organic Frameworks: Gas Storage, Separation and Catalysis.</a> Topics in Current Chemistry. (ed Martin Schr&#246;der) Ch. 293, 1-33 (2010).</li><li>Dawson, R., Cooper, A. I., Adams, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoporous+organic+polymer+networks.">Nanoporous organic polymer networks.</a> Progress in Polymer Science. 37 (4), 530-563 (2012).</li><li>Muller, T., Br&#228;se, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Click+Chemistry+Finds+Its+Way+into+Covalent+Porous+Organic+Materials.">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. 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The authors have nothing to disclose.

Für die Synthese von CMP-Film der Lösung des Katalysators hat frisch. Ein gebrochener Katalysator (dh oxidiert) wird durch eine Blaufärbung der Lösung angezeigt. Die frische Lösung ist farblos. Ein entscheidender Punkt ist, um die Kanten des Glimmer-Substrat nach der Schleuderbeschichtung PMMA geschnitten. Auch Defekte in dem Substrat geschnitten werden soll, das heißt, jeder Punkt waren die PMMA kann in Kontakt mit dem Glimmer-Substrat wegen einer fehlenden ...

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 große Oberfläche Materialien angezogen zunehmendes Interesse vor kurzem auf Grund ihrer hohen Variabilität bei der Einarbeitung von funktionellen Gruppen in Kombination mit ihrer hervorragenden thermischen und chemischen Stabilität und niedrigen Dichten. Jedoch verursacht ihre Unlöslichkeit Probleme bei ihrer Verarbeitung da üblicherweise angewandte Techniken wie Schleuderbeschichtung sind nicht verfügbar. Besonders für Membrananwendungen, wobei die Verarbeitung der CMP als dünne Filme wünschenswert sind die Verarbeitungsprobleme ihre kommerzielle Anwendung verhindert. Hier beschreiben wir die Grenzflächensynthese von CMP Dünnschichten auf funktionalisierten Substraten über molekulare Schicht-für-Schicht (LBL) Synthese. Dieses Verfahren erlaubt die Herstellung von Filmen mit einer gewünschten Dicke und Zusammensetzung und sogar gewünschten Zusammensetzungsgradienten. Die Verwendung von Opfer Trägern ermöglicht die Herstellung von freistehenden Membranen durch Auflösen des Trägers nachdie Synthese. Um solche ultradünnen Membranen freistehenden Griff der Schutz mit Opferbeschichtungen zeigten großes Versprechen, zum Bruch der Nanomembranen zu vermeiden. Um die Nanomembranen auf das gewünschte Substrat übertragen werden die beschichteten Membranen an der Luft-Flüssigkeit-Grenzfläche upfloated und dann über Tauchbeschichtung überführt.

Die Membranen werden durch Infrarotreflexionsabsorptionsspektroskopie (IRRAS). Gekennzeichnet 16 Abbildung 4 zeigt IRRA-Spektren von einem CMP-Membran auf eine Gold-Wafer übertragen. Typische Banden aus den Schwingungen des aromatischen Rückgrat sind 1.605 cm -1, 1.515 cm -1 und 1,412 cm -1. Nicht umgesetztem Alkin- und Azidgruppen können durch charakteristische Banden bei 2.125 cm -1 und 1,227 cm -1 beobachtet werden. 5 zeigt ...

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.

Layer-by-Layer-Synthese und Übertragung von Freestanding konjugierte mikroporöse Polymernanomembranen

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

layer-layer-synthesis-transfer-freestanding-conjugated-microporous

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Chemistry

9.3K Aufrufe.  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.

Serie: 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.

Gegen biomimetischen Holz: Hergestellt Freistehende Filme aus Nanocellulose, Lignin und eines synthetischen Polykation

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

Forschung

Chemie

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.

Eine Technik, um auf Vorlage freie Substrate zu funktionalisieren und Selbstorganisation makroskopische Nanopartikel-Liganden-Monolayer Films

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.

Herstellung von großflächigen Freistehende ultradünne Polymerfilme

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

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.

Bildung Biomembrane Microarrays mit einem Rakel-basierten Montageverfahren

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

Biotechnik

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.

Herstellung der lichtreaktions Membranen durch eine Kombinierte Oberflächen-Pfropfen und Postmodification Prozess

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.

Herstellung von reaktiven Oberflächen mit Pinsel-Like und querverbunden Filme von Azlactone funktionalisiert Block-Copolymere

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

Ingenieurwesen

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.

Elektrophoretische Kristallisation von ultradünnen Hochleistungs-Metall-organischen Rahmen Membranen

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.

Verfahren zur Übertragung von Polymerfolien auf poröse Substrate mit minimierten Defekten

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

Preparation of Thermoresponsive Nanostructured Surfaces for Tissue Engineering

Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm)-immobilized surfaces for controlling cell adhesion and detachment were fabricated by the Langmuir-Schaefer method. Amphiphilic block copolymers composed of polystyrene and PIPAAm (St-IPAAms) were synthesized by reversible addition-fragmentation chain transfer (RAFT) radical polymerization. A chloroform solution of St-IPAAm molecules was gently dropped into a Langmuir-trough apparatus, and both barriers of the apparatus were moved horizontally to compress the film to regulate its density. Then, the St-IPAAm Langmuir film was horizontally transferred onto a hydrophobically modified glass substrate by a surface-fixed device. Atomic force microscopy images clearly revealed nanoscale sea-island structures on the surface. The strength, rate, and quality of cell adhesion and detachment on the prepared surface were modulated by changes in temperature across the lower critical solution temperature range of PIPAAm molecules. In addition, a two-dimensional cell structure (cell sheet) was successfully recovered on the optimized surfaces. These unique PIPAAm surfaces may be useful for controlling the strength of cell adhesion and detachment.

Nanoscaled sea-island surfaces composed of thermoresponsive block copolymers were fabricated by the Langmuir-Schaefer method for controlling spontaneous cell adhesion and detachment. Both the preparation of the surface and the adhesion and detachment of cells on the surface were visualized.

Herstellung von Thermoresponsive nanostrukturierte Oberflächen für Tissue Engineering

Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm)-immobilized surfaces for controlling cell adhesion and detachment were fabricated by the ...

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>Mikroskopische Visualisierung von porösen Nanographenen, die durch eine Kombination aus Lösungs- und Oberflächenchemie synthetisiert werden

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.