Reversible polymers from self-complementary monomers, using quadruple hydrogen bonding

Units of 2-ureido-4-pyrimidone that dimerize strongly in a self-complementary array of four cooperative hydrogen bonds were used as the assocg. end group in reversible self-assembling polymer systems. The unidirectional design of the binding sites prevents uncontrolled multidirectional assocn. or gelation. Linear polymers and reversible networks were formed from monomers with two and three binding sites, resp. The thermal and environmental control over lifetime and bond strength makes many properties, such as viscosity, chain length, and compn., tunable in a way not accessible to traditional polymers. Hence, polymer networks with thermodynamically controlled architectures can be formed, for use in, for example, coatings and hot melts, where a reversible, strongly temp.-dependent rheol. is highly advantageous