Dynamic Perspective on the Function of Thermoresponsive Nanopores from in Situ AFM and ATR-IR Investigations

详细信息    查看全文

• 作者：Ana Maria Popa ; Silvia Angeloni ; Thomas Brgi ; Jeffrey A. Hubbell ; Harry Heinzelmann ; Raphal Pugin
• 刊名：Langmuir
• 出版年：2010
• 出版时间：October 5, 2010
• 年：2010
• 卷：26
• 期：19
• 页码：15356-15365
• 全文大小：1176K
• 年卷期：v.26,no.19(October 5, 2010)
• ISSN：1520-5827

文摘

This article describes the morphological and chemical characterization of stimuli-responsive functionalized silicon surfaces provided in parallel by atomic force spectroscopy (AFM) and Fourier transform infrared spectroscopy (FT-IR) enhanced by the single-beam sample reference attenuated total reflection method (SBSR-ATR). The stimuli-responsive behavior of the surfaces was obtained by grafting-to in melt carboxyl-terminated poly-N-isopropylacryl amides (PNIPAAM) with different degree of polymerization (DP) on epoxide-functionalized silicon substrates. The unprecedented real time and in situ physicochemical insight into the temperature-triggered response of the densely packed superficial brushes allowed for the selection of a PNIPAAM with a specific DP as a suitable polymer for the fabrication of silicon membranes exhibiting switchable nanopores. The fabrication process combines the manufacture of nanoporous silicon surfaces and their subsequent chemical functionalization by the grafting-to in melt of the selected polymer. Then, relevant information was obtained in what concerns the chemical modifications behind the topographical changes that drive the functioning of PNIPAAM-based hybrid nanovalves as well as the timescale on which the opening and closing of the nanopores occur.