dc.description.abstract | Energy demand triggers people to find other renewable energy alternatives, such as fuel cell. In this study composite membrane of sulfonated polysulfone-sodium alginate (sPSf) was synthesized characterized and then applied in direct methanol fuel cell. Sulfonation was started at 40 oC for 1 hour and then sodium alginate was added to improve membrane performances. The degree of sulfonation through sulfonation process was 45% and a peak at 1725 cm-1 in Fourier transform infrared spectrophotometer showed that 1,2,4- substituted sulfonate group exist in ortho position. Composite membrane was produced by adding sulfonated polysulfone and sodium alginate with concentration of 2% and 3%. The composite membrane of sPSf-sodium alginate 3% gave the highest proton conductivity and voltage with values 1.634 х10-3 S/cm and 0.409 volt, respectively. This result showed that the composite membrane of sPSf-sodium alginate can be applied in direct methanol fuel cell system | en |