Polymer-based fluoride-selective chemosensor: Synthesis, sensing property, and its use for the design of molecular-scale logic devices

Abstract

A new styryl-type monomer, 2-(4-vinylbenzyloxy)-1-naphthaldehyde thiosemicarbazone (VNT), was synthesized and then copolymerized with methyl methacrylate (MMA) by reversible addition fragmentation chain transfer polymerization affording a series of poly(MMA-co-VNT)s with different functional unit content, predetermined molecular weight, and narrow molecular-weight distribution. The desired copolymers were structurally confirmed by various spectroscopic characterizations. Colorimetric and fluorescent titration spectra revealed that the copolymers are highly selective toward fluoride anions over other competitive species including Cl -, Br -, I -, H 2PO 4 -, AcO -, and HSO 4 -. On addition of F -, a remarkable colorless-to-yellow color change is easily observed by naked eyes. The influence of the copolymer composition and molecular weight on its sensing capacity was then carefully investigated. The results showed that higher VNT-incorporation amount within the copolymer chains leads to higher sensitivity toward F - ions. Interestingly, the chromogenic process of the polymeric sensor can be switched back and forth by successively adding F - and HSO 4 - anions into the dimethyl sulfoxide solution of the polymer, which may be represented by a complementary "IMPLICATION/ INHIBIT" logic gate at molecular level using both the ions as the chemical inputs. Based on such a reversible and reproducible sensing system, we designed a molecular-scale sequential information processing circuit displaying "writing-reading-erasing-reading" behavior and "multiwrite" function in the form of binary logic. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 A new kind of polymeric sensory materials has been synthesized through reversible addition fragmentation chain transfer polymerization technique. The polymer receptor exhibited high selectivity toward fluoride anions in both UV-vis and fluorescence channels. Especially, the fluoride-induced chromogenic process could be fully reversed by the addition of HSO 4 -. The reversible and reproducible characteristics of the colorimetric switch allow the design of a molecular-scale sequential memory unit displaying "writing-reading-erasing-reading" behavior and "multiwrite" functions. Copyright © 2011 Wiley Periodicals, Inc.