Morphology and Topography Studies of Composite Membranes Developed from Chitosan/Phthaloyl Chitosan Consisting Multi-Walled Carbon Nanotube/Montmorillonite as Filler

This work discusses the synthesis and characterizations of the newly developed composite membranes based on chitosan/phthaloyl chitosan (Cs/PhCs) as a matrix with various compositions of multi-walled carbon nanotube/montmorillonite (MWCNT/MMT) filler. The Cs/PhCs/MWCNT/MMT composite membranes are synthesized via the solvent evaporation method and were investigated by Fourier Transform Infrared (FTIR), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and DMFC single cell test. The FTIR characterization result showed that all membranes have origin peaks at 3433, 2943, and 1525 cm-1 contributed to vibrations of O-H, C-H, and N-H group, respectively. Meanwhile, the composite membranes with 7.5 and 8 wt.% filler have characteristic peaks of vibration Si-O-Si, Si-OH, and Si-O at 1209, 886, and 591 cm-1 respectively. Cross-sectional micrographs of SEM and AFM revealed that the composite membrane with 7.5 wt.% filler had moderate surface roughness than the other as-fabricated membranes. As a result, this nanocomposite membrane can be an alternative polyelectrolyte membrane for DMFC applications. The resulting Cs/PhCs/MWCNT/MMT-1 composite membrane has the selectivity up to 5.13×105 S.s.cm-3 with the DMFC performance at 23.60 mW cm-2.Keywords: chitosan, carbon nanotube, morphology, topography, direct methanol fuel cell