Chunliu FANG

Ph.D. Student 2008-2012 NUS Graduate School for Integrative Sciences and Engineering (NGS)   CONTACT      EDUCATION  M.S., Chemistry, University of Science and Technology of China, 2008   RESEARCH INTEREST

My research interest is to develop a high performance alternative proton exchange membrane (PEM). 

In a direct methanol fuel cell (DMFC) system, the role of a PEM is to allow the transfer of protons from anode to cathode while preventing significant diffusion of methanol. A typical PEM is composed of two components, namely, hydrophilic and hydrophobic moieties. The former usually contains sulfonic acid groups and contributes to water adsorption and proton transport, while the latter maintains mechanical strength and dimensional stability of membranes. It is widely accepted that the PEM microstructure plays an important role in affecting the final transport properties. For example, the proton transport in a PEM is to pass through some connective hydrophilic channels, which form from the microphase separation between the hydrophilic and hydrophobic moieties.  

In order to achieve a controllable microstructure, it requires a better understanding of the factors that affect membrane microstructure and critical PEM properties (e.g., proton conductivity, methanol permeability, water uptake, dimensional stability, and etc.). 

Among the alternative PEMs, the semi-interpenetrating polymer network (SIPN) is an attractive structure. It is a special class of polymer composites where one or more linear (or branched) polymers percolate molecularly into a network of other polymers. In comparison with simple polymer blends or cross-linked PEMs, SIPNs have the potential of offering a better control on the microstructure and the properties of the resultant materials. Through tuning the temperature and composition of the reaction mixture, especially the proportion of the dispersed phase, the SIPNs can developed a microphase co-continuous morphology which realizes the maximum connection of hydrophilic domains. In addition, the interlocking mechanism of SIPNs can lead to imposed miscibility between incompatible constituents and the enhancement of mechanical properties. In our work, we systematically studied the effect of cross-linkers on the microstructure and PEM properties of SIPN membranes. The aim of our study is to gain a better understanding of structure-property relationship and hence control and optimization of the SIPN PEM properties. So far, good performance PEMs have been prepared by our group.