Menut P.Su Y.S.Chinpa W.Pochat-Bohatier C.Deratani A.Wang D.MHuguet P.Kuo C.Y.Lai J.Y.Dupuy C.2019-05-032019-05-03200803767388https://scholars.lib.ntu.edu.tw/handle/123456789/406383The formation of a surface liquid layer on the top of membrane forming systems made of poly(ether-imide) (PEI) and N-methylpyrrolidone (NMP) was clearly demonstrated during water vapor-induced phase separation (VIPS) through several in situ investigation methods including optical microscopy and dynamic water contact angle measurements for a qualitative approach, and Raman confocal and FTIR microscopy for a quantitative one. A mechanism involving the shrinkage from the polymer-rich phase consecutively to the surface phase separation is proposed to account for the significantly high concentration of PEI in the surface liquid layer. The emergence of a surface liquid layer during the phase separation process is discussed in terms of implications on morphology of membrane fabricated using VIPS and how it contrasts with liquid-induced phase separation. ? 2007 Elsevier B.V. All rights reserved.In situ analysisMembrane morphologyPoly(ether-imide)Surface liquid layerVapor-induced phase separationjournal article10.1016/j.memsci.2007.11.0162-s2.0-38649137278https://www.scopus.com/inward/record.uri?eid=2-s2.0-38649137278&doi=10.1016%2fj.memsci.2007.11.016&partnerID=40&md5=06c6305a0a48bdfdf31fa4d017bf7b51