Sintesi layer-by-layer e di trasferimento delle Freestanding coniugati microporosi Polymer nanomembrane
Summary
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.
Abstract
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'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'interfaccia aria-liquido e quindi trasferiti tramite dip coating.
Introduction
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.
Protocol
Representative Results
Discussion
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 …
Disclosures
The authors have nothing to disclose.
Acknowledgements
The authors have no acknowledgements.
Materials
| Acetone | VWR BDH Prolabo | 20066.330 | AnalR NORMAPUR |
| Potassium iodide | VWR BDH Prolabo | 26846.292 | AnalR NORMAPUR |
| Ethyl acetate | VWR BDH Prolabo | 23882.321 | AnalR NORMAPUR |
| Tetrahydrofurane (THF) | VWR BDH Prolabo | 28559.320 | HiPerSolv CHROMANORM |
| THF waterfree | Merck Millipore | 1.08107.1001 | SeccoSolv |
| Iodine | Sigma-Aldrich | 20,777-2 | |
| Tetrakis(acetonitrile)copper(I)hexafluoro-phosphate | Sigma-Aldrich | 346276-5G | |
| Poly(methyl methacrylate) 996 kDa (PMMA) | Sigma-Aldrich | 182265-25G | |
| 1.1.1.1 Methanetetrayltetrakis(4-azidobenzene) (TPM-azide) | provided by AK Prof. Bräse. Institute of organic chemistry, Karlsruhe Institute of Technology. Synthesized according to9 | ||
| 1.1.1.1 Methanetetrayltetrakis(4-ethinylenebenzene) (TPM-alkyne) | provided by AK Prof. Bräse. Institute of organic chemistry, Karlsruhe Institute of Technology. Synthesized according to9 | ||
| 11-thioacetyl-undecaneacid propargylamide | provided by AK Prof. Bräse. Institute of organic chemistry, Karlsruhe Institute of Technology. Synthesized according to8 | ||
| gold/titan coated silicium-wafer | Georg Albert PVD, 76857 Silz, Germany | ||
| gold coated mica | Georg Albert PVD, 76857 Silz, Germany |
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