Gallol-Containing Polymers: Synthesis and Applications

The presence of gallol units in a macromolecule entails specific or improved characteristics and intrinsic properties of the macromolecule. The rationale behind such spin-offs is indubitably the structural fact of the gallol group, being 1,2,3-trihydroxybenzene. Pyrogallol (PG), gallic acid (GA), tannic acid (TA), and epigallocatechin gallate (EGCG) would be of a great value once they are parts of a polymer integrity, and, being naturally occurring molecules, the value would certainly rise further. The gallic molecule imputed to the polymer conjugate higher antioxidant and antimicrobial activities, particularly in form of hydrogels and nanoparticles. As with catechol units in marine-inspired materials, the gallol ones of a conjugate ensure its adhesiveness on multiple substrata in a wet environment, and more efficiently than the catechol counterpart. PG and GA were mostly polymerized via oxidative polymerization as: self-polymerization and electrochemical/enzymatic polymerization. In several cases, the radical polymerization of some protected vinylgallol-containing monomers ended up with gallol-bearing polymers after deprotection. Some gallol monomers are prone to copolymerize with vinyl comonomers such as divinylbenzene, and to polycondensate with aldehydes such as formaldehyde and benzaldehydes, and others such as polyamines. Polycondensation of tannic acid (TA) and triethylenetetramine via Michael addition reaction is but one example. The third route to realize gallol-containing polymers is to chemically functionalize or conjugate the premade polymers with gallolic molecules (PG, GA, EGCG, TA) under conventional or special chemistry. [GRAPHICS] .