title: High internal phase emulsion with double emulsion morphology and their templated porous polymer systems.
abstract: This paper reports synthesis of the first high internal phase emulsion (HIPE) system with double emulsion (DE) morphology (HIPE-DE). HIPE is a highly concentrated but highly stable emulsion system, which has a dispersed/internal phase fraction over 74vol%. DE represents an emulsion system that hierarchically encapsulates two immiscible phases. The combination of HIPE and DE provides an efficient method for fabrication of complex structures. In this work, HIPE-DE having a water-in-oil-in-water (W/O/W) morphology has been prepared for the first time via a simple one-step emulsification method with poly(2-(diethylamino)ethyl methacrylate) (PDEA) microgel particles as Pickering stabilizer. An oil phase fraction up to 90vol% was achieved by optimizing the microgel concentration in aqueous phase. The mechanism of the DE formation has been elucidated. It was found that while PDEA microgels stabilized the oil droplets in water, small amount protonated DEA monomers acted as surfactant and formed water-containing micelles inside the oil droplets. It was demonstrated that the W/O/W HIPE-DE could be precisely converted into porous polymer structures. With styrene as the oil phase in W/O/W HIPE-DE, porous polystyrene particles were obtained upon polymerization. With dissolved acrylamide as the aqueous phase and toluene as the continuous phase, porous polyacrylamide matrixes were prepared. Elevating temperature required for polymerization did not change the W/O/W HIPE-DE morphologies. This simple approach provides a versatile platform for synthesis of a variety of porous polymer systems.
authors: Department of Chemical Engineering, McMaster University, Hamilton L8S 4L7, Canada.
authors: Lei
authors: L
authors: Lei
authors: College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
authors: Qi
authors: Q
authors: Zhang
authors: Key Laboratory of Carbon Fiber and Functional Polymers (Ministry of Education), Beijing University of Chemical Technology, Beijing 100029, China. Electronic address: shisx@mail.buct.edu.cn.
authors: Shuxian
authors: S
authors: Shi
authors: Department of Chemical Engineering, McMaster University, Hamilton L8S 4L7, Canada. Electronic address: zhuship@mcmaster.ca.
authors: Shiping
authors: S
authors: Zhu
keywords: Double emulsion; High internal phase emulsion; PDEA microgel; Pickering emulsion; Porous polymer products