Supercritical carbon dioxide

Communication

Supercritical Carbon Dioxide-Treated Electrospun Poly(vinylidene fluoride) Nanofibrous Membranes: Morphology, Structures and Properties as an Ionic-Liquid Hosta
Wu Aik Yee, Shanxin Xiong, Guoqiang Ding, Chien Anh Nguyen, Pooi See Lee, Jan Ma, Masaya Kotaki, Ye Liu, Xuehong Lu*

A reverse-barrier technique is used to enable the treatment of electrospun poly(vinylidene fluoride) nanofibrous membranes with supercritical carbon dioxide. The treatment induces the formation of nanopores and extended-chain b crystallites of small lateral dimensions in the nanofibers. It also creates interfiber junctions, resulting in a remarkable improvement in mechanical properties of the membranes. The treated membranes are able to retain their shape very well after loading with an ionic liquid (IL). The ionic conductivity of the IL-loaded membrane is very close to that of the neat IL.

Introduction
In the past few years, ionic liquids (ILs) have been increasingly explored as the electrolytes in various
X. Lu, W. A. Yee, S. Xiong, G. Ding, C. A. Nguyen, P. S. Lee, J. Ma School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore E-mail: [e-mail] M. Kotaki Division of Advanced Fibro Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan Y. Liu Institute of Materials Research & Engineering, 3 Research Link, 117602, Singapore a : Supporting information for this article is available at the bottom of the article’s abstract page, which can be accessed from the journal’s homepage at http://www.mrc-journal.de, or from the author.

electrochemical devices due to the excellent thermal, chemical, and electrochemical stabilities of the ILs as well as their high ionic conductivity over a wide temperature range.[1] Many polymers have been investigated for hosting the ILs,[1–6] among which poly(vinylidene fluoride) (PVDF) and its copolymers have been identified as one of the most