Novel applications of fluorescent brighteners in aqueous visible-light photopolymerization: high performance water-based coating and LED-assisted hydrogel synthesis

Commercial fluorescent brighteners (styrene-based, coumarine-based and 2,5-bis(benzoxazolyl)thiophene-based derivatives) are shown to be active photoinitiators in aqueous visible-light photopolymerization. The proposed systems are characterized by: (i) a low intensity visible-light photopolymerization reaction of acrylates in water using a unique photoinitiating system consisting of a catalytic amount of commercially available optical brighteners and diphenyliodonium salt and (ii) a category of more ecofriendly acrylate formulations enabling the LED-assisted synthesis of hydrogels that typically show high swelling capability. Herein, styrene-based brighteners show their potential as the most promising photoinitiators for the synthesis of tack free waterborne coatings and hydrogels under mild light irradiation conditions, i.e. safe and cheap irradiation devices were selected.