Light responsive with metallo-, and hydrogen bonded benzoxazine dimer-based supramolecular structure

Abstract

The present work focuses on multi-responsive molecule based on supramolecular chemistry of benzoxazine dimer as a benzoxazine supramolecular crosslinker, fluorescent labelling benzoxazine conjugated with rotaxane system and benzoxazine pendant group block copolymer. The use of azobenzene derivatives in benzoxazine synthesis provides light responsive behaviour. The remained hydroxyl group from aminoalcohol allows benzoxazine to conjugate with desired functional group. The dihydroxyl benzoxazine acts as molecular crosslinker for poly(acrylic acid) by conjugation. The ring-opening reaction brings benzoxazine dimeric unit on the crosslinker which also showed metal ion complexation. The complexation strengthens the cross-linked polymer network. The complex can reversely form by treating with EDTA and CuCl₂ solution in cycle. The use of fluorescent phenol in the ring opening also brings fluorescent property. The conjugation of light responsive benzoxazine with rotaxane system followed with ring opening reaction using fluorescent phenol allows us to detect the shuttling of rotaxane. Moreover, the metal ion complexation and cis/trans isomerization were also detected by fluorescent property. The benzoxazine side group polymer can be obtained from conjugation of light responsive benzoxazine with acrylate derivatives. The polymerization with ATRP provides block copolymer. The UV light exposure and metal ion complexation affects morphology of the block copolymer.