New design of phenol-containing polymers as radical scavengers

Oxygen is critical for living creatues to generate energy; however, it can be detrimental to cause cancer, aging etc., when the resultant reactive oxygen species (ROSs) and antioxidant defence are not in the balance. As a typical example, phenol-containing molecule plays a important role in acting against ROS. This chapter describes the very recent development of new synthetic phenol-containing polymers as effective free radical scavengers in aqueous environment, such as a phenolic resin (particularly novolac resin) grafted with hydrophilic poly(ethylene glycol) (PEG) by click chemistry. Due to the amphiphilic nature, the new polymer selfassembles to form colloidally-stable micelles with hydrophobic novolac cores surrounded with hydrophilic PEG chains. The micelles exhibit noncytotoxicity and quick response to hydroxyl radicals, protecting indicator molecule Crystal Violet from being bleached in water. Further, another phenol-containing polymeric radical scavenger, a catecholcontaining polymer synthesized from dopamine by free radical polymerization, is presented. The new research including nano-aggregates by self-assembly enriches the synthetic methodologies in fighting against ROS in the future.