(168c) Effect of Isopropyl Phosphate Incorporation on the Morphology and Transport Properties of Sulfonated Poly(styrene-isobutylene-styrene) Membranes

This investigation focuses on the incorporation of phosphorus groups to improve the performance of sulfonated poly(styrene-isobutylene-styrene) (SIBS) in direct methanol fuel cell applications (DMFC). Membranes of a blend between sulfonated SIBS and isopropropyl phosphate (IP) were prepared. The unique interactions between the phosphate and sulfonate groups influence the transport mechanism of protons and methanol. The resulting membranes with additional ionic domains were characterized to understand the resulting nanostructure and their effect on the transport properties for DMFC applications. Material characterization techniques employed include Fourier-Transform Infrared Spectroscopy (FT-IR), Thermal Gravimetric Analysis (TGA), Atomic Force Microscopy (AFM), and Small Angle X- ray Scattering (SAXS). In addition, transport properties such as methanol permeability; proton conductivity and others were measured to understand the connection between the resulting nanostructure and material applications. The intellectual merit of this investigation is the development of novel proton exchange membranes (PEMs) with unique ionic domains to enhance DMFC applications, while understanding how critical parameters (e.g., chemistry, water absorption and morphology) affect the proton transport mechanism within the membranes.