Intercalation and Confinement of Poly(ethylene oxide) in Porous Carbon Nanoparticles with Controlled Morphologies
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- 作者：Fabienne Barroso-Bujans ; Pablo Palomino ; Felix Fernandez-Alonso ; Svemir Rudi膰 ; Angel Alegr铆a ; Juan Colmenero ; Eduardo Enciso
- 刊名：Macromolecules
- 出版年：2014
- 出版时间：December 23, 2014
- 年：2014
- 卷：47
- 期：24
- 页码：8729-8737
- 全文大小：455K
- ISSN：1520-5835
文摘
Polymers confined at the nanometer scale often exhibit a distinct structural and dynamical response compared to their bulk counterparts. In this study, we observe that the confinement of poly(ethylene oxide) (PEO) in the nanopores of carbon nanoparticles (CNPs) leads to the suppression of crystallization and to a significant reduction of the 螖Cp at the glass transition. We ask whether these changes are dominated by interfacial interactions (van der Waals type) or by geometrical constraints. For pore diameters below 2 nm (micropores following IUPAC nomenclature), we find that the larger the pore surface, the higher the amount of PEO intercalated in the micropores and, consequently, the larger the reduction of the 螖Cp at the glass transition (up to 50%). For pore diameters in the range 2鈥?0 nm (mesopores), larger pore surfaces lead to a higher amount of PEO adsorbed on the mesopore walls and the smaller the reduction of the 螖Cp at the glass transition. Under these conditions of spatial confinement at the nanoscale, PEO chains cannot arrange themselves into large crystalline domains, as evidenced by a negligible degree of crystallization of at most 1.8%. High-resolution inelastic neutron scattering data show that the PEO chains confined in the pores of CNP adopt a planar zigzag conformation, which is distinctly different from those characteristic of the 7/2 helical structure of the bulk crystal.