Using polymeric additives to enhance molecular gelation: impact of poly(acrylic acid) on pyridine-based gelators

The effect of polymeric additives on molecular gelation was explored using poly(acrylic acid) and pyridine-based gelators. A significant reduction in the critical gel concentration (cgc) and an increase in gel strength were observed when the polymer was present during gel formation. Detailed studies revealed that the polymer is adsorbing onto the growing fibers, reducing the growth rates, and leading to thinner fibers. These and other morphological changes lead to improved gel properties by increasing the number of fiber-fiber entanglements. Several other polymers were briefly examined and these studies revealed that polymer structure is important. The polymer containing a complementary functional group relative to the gelator (e.g., H-bond donor/acceptor) provided the lowest cgc.