Concise synthesis of a light/temperature/pH/CO2-quadruple responsive azobenzene functionalized homopolymer for reversible photopatterning

• Published in: Polymer chemistry Vol. 15; no. 37; pp. 3795 - 3805
• Main Authors: Wang, Ke, Si, Meiyu, Liu, Xiaofang, Wang, Zilong, Liu, Guiyan, Zeng, Yongfei
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 24.09.2024
• Subjects: Absorption spectra; Addition polymerization; Aqueous solutions; Azo compounds; Benzoates; Butanol; Carbon dioxide; Chain transfer; Light irradiation; Micelles; Molecular structure; Self-assembly; Ultraviolet radiation
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/d4py00669k

A novel light/temperature/pH/CO2-quadruple responsive azobenzene functionalized homopolymer of poly[(E)-3,14-dimethyl-13-oxo-6,9,12-trioxa-3-azapentadec-14-en-1-yl 4-(phenyldiazenyl)benzoate] [P(Azo-N-EO2MA)] was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. The light-responsiveness of P(Azo-N-EO2MA) was demonstrated by examining the UV/vis absorption spectra under alternating UV/blue light irradiation or UV irradiation/heating conditions. P(Azo-N-EO2MA) has an upper critical solution temperature (UCST) in the co-solvent of n-butanol/water and a critical pH in aqueous solution. The effects of different molecular structures, molecular weights and concentrations on the UCST and critical pH were investigated. The response of P(Azo-N-EO2MA) to CO2 was demonstrated via the cyclic bubbling of CO2/N2 through a solution of P(Azo-N-EO2MA). Then, the interaction between the different response was explored. The critical micelle concentration (cmc) of P(Azo-N-EO2MA) was tested. Micelles of P(Azo-N-EO2MA) were prepared by self-assembly, and the morphology or size of the micelles can be changed by applying acid or irradiating with UV light. Finally, P(Azo-N-EO2MA) was applied to the preparation of rewritable paper, and it is proved that the rewritable paper has good cyclability, stability and high resolution during the process of “writing–erasing–writing” of different patterns. P(Azo-N-EO2MA) expands the types of multistimuli-responsive homopolymers available to researchers and has good prospects for applications in self-assembly, drug delivery and optical storage.