Structural Study on Polymer in Ionic Liquid System

Abstract

We report our recent structural study on the polymer in room-temperature ionic liquid (IL) solutions by using neutron/X-ray scattering. Small-angle neutron scattering (SANS) measurement was made on poly(benzyl methaceyrate) (PBnMA) in fully deuterated 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C₂mIm] [TFSA]) solution and the LCST phase behavior was characterized from the structural viewpoint. The SANS was also carried out for poly(N-isopropyl acrylamide) (PNIPAm) in IL which shows UCST phase separation. It was found from the results that the phase behavior strongly depends on the solvation of polymers at the local scale. Therefore, we tried to perform high-energy X-ray diffraction for the polymer solutions, which allow us to discuss the microscopic solvation structure. We finally discussed the relationship between nano- and micro-scale structures in the polymer/IL systems.