Abstract
The synthesis, thermal, mechanical and conduction properties of blends of a cationic polyelectrolyte, poly-(diallyldimethylammonium- dihydrogenphosphate), 'PAMA exp + H sub 2 PO sub 4 exp - ', and phosphoric acid are reported. The dc conductivity increases with x and reaches 10 exp -4 S/cm at ambient temperature and 10 exp -2 S/cm at 100 deg C for PAMA exp + H sub 2 PO sub 4 exp - 2H sub 3 PO sub 4 . The exp 1 H- and exp 31 P-self- diffusion coefficients of PAMA exp + H sub 2 PO sub 4 exp - xH sub 3 PO sub 4 for x = 1, 2 were determined by PFG-NMR. D sub (H) is always at least one order of magnitude larger than D sub (P) , which means that inter-phosphate H exp + transfer plays an important role in the samples. D sub (H) coincides quite well with the conductivity diffusion coefficient D sub sigma which is obtained from the conductivity data via the Nernst-Einstein relationship, assuming that the charge carrier concentration is equal to the repeat unit concentration. Since with the same assumption the charge carrier concentration is only (3x + 2) exp -1 times the concentration of all the phosphate protons, the result D sub sigma /D sub (H) approx = 1 is rather surprising and indicative of cooperative proton transfer which does not contribute to the conductivity. D sub (H) /D sub (P) in the blends is much larger than D sub (H) /D sub (P) in pure phosphoric acid. This means that the phosphate moieties are considerably more immobilized in the blends as compared to H sub 3 PO sub 4 . This immobilization effect is more pronounced in blends with low phosphoric acid content and decreases with increasing temperature.