title: Interfacing a tetraphenylethene derivative and a smart hydrogel for temperature-dependent photoluminescence with sensitive thermoresponse.
abstract: We report, for the first time, the design and synthesis of thermoresponsive (TR) photoluminescent (PL) hydrogel nanoparticles, with a core consisting of poly[styrene-co-(N-isopropylacrylamide)] (PS-co-PNIPAM) and a PNIPAM-co-PAA shell. PAA represents polyacrylic acid which interacts with our emitting molecule 1,2-bis[4-(2-triethylammonioethoxy)phenyl]-1,2-diphenylethene dibromide (d-TPE). The electrostatic interaction between each water-soluble d-TPE molecule and two AA repeat units activates these d-TPE molecules to exhibit strong PL. Our d-TPE doped PS-co-PNIPAM/PNIPAM-co-PAA particles in water display remarkable TR PL: the emission intensity decreased in the course of heating from 2 to 80 °C and recovered during cooling from 80 to 2 °C. Such linear, reversible, and sensitive TR PL is achieved by the use of both PAA and PNIPAM as the shell polymeric chain and by careful optimization of the d-TPE to AA feed molar ratio. Thus, the emission of the d-TPE molecule is affected sensitively by temperature. In addition to such an exceptionally temperature-dependent PL, the presence of CrO4(2-) resulted in the decrease of the emission intensity, which was also temperature-dependent. The present study provides a unified conceptual methodology to engineer functional water-dispersible hydrogel nanoparticles that are stimuli-responsive with the potential to advance various PL-based applications.
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun, 130012, P. R. China.
authors.forename: Yingnan
authors.initials: Y
authors.lastname: Jiang
authors.forename: Xudong
authors.initials: X
authors.lastname: Yang
authors.forename: Cheng
authors.initials: C
authors.lastname: Ma
authors.forename: Chuanxi
authors.initials: C
authors.lastname: Wang
authors.forename: Yang
authors.initials: Y
authors.lastname: Chen
authors.forename: Fengxia
authors.initials: F
authors.lastname: Dong
authors.forename: Bai
authors.initials: B
authors.lastname: Yang
authors.forename: Kui
authors.initials: K
authors.lastname: Yu
authors.forename: Quan
authors.initials: Q
authors.lastname: Lin