Rheological and micro-DSC studies on the aqueous mixtures of methylcellulose and ammonium poly(3-thiophene acetic acid)

In the present work aqueous mixtures of polysaccharide of methylcellulose (MC) and conductive polymer of ammonium poly(3-thiophene acetic acid) (PTAA-NH4) were prepared and the effect of PTAA-NH4 on the rheological and thermal properties of MC solution were investigated. Significant viscous synergism depending on shear rate and concentration of PTAA-NH4 was found for the mixtures, indicating a special interaction between the two amphiphilic polymers of MC and PTAA-NH4. In comparison with pure MC solutions, the mixtures showed much more evident shear thinning characteristics. When the concentration of PTAA-NH4 added was higher than 0.15%, weak gel-like behavior of the mixtures was also observed at low temperatures. In addition, though the gelation and degelation patterns of MC were not changed by the addition of PTAA-NH4, both rheological and calorimetric measurements showed that the presence of PTAA-NH4 shifted the sol–gel transition temperature of MC solution to higher temperature with increasing of the concentration of PTAA-NH4.