Synthesis of block copolymers derived from N-trityl-(S)-serine and pyrene end-labeled poly(methyl methacrylate) or poly(N-isopropylacrylamide) via ATRP

• Published in: Journal of luminescence 2012-10, Vol.132 (10), p.2704-2713
• Main Authors: Buruiana, Emil C., Podasca, Viorica, Buruiana, Tinca
• Format: Article
• Language: English
• Subjects: Amino acid; Applied sciences; ATRP; Block copolymers; Differential scanning calorimetry; Exact sciences and technology; Fluorescence; Monomers; Nitrophenol; Organic polymers; Physicochemistry of polymers; Polymerization; Polymers with particular properties; Polymethyl methacrylates; Preparation, kinetics, thermodynamics, mechanism and catalysts; Pyrenes; Scanning electron microscopy
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2012.05.019

A new monomer bearing N-trityl-l-serine methyl ester in structure, methacryloyloxyethyl carbamoyloxy–N-trityl methyl serine (MTS), was prepared to be further polymerized by atom transfer radical polymerization (ATRP) with pyrene-endcapped poly(methyl methacrylate) (Py–PMMA–Br) or poly(N-isopropylacrylamide) (Py–PNIPA–Br). The resulting block copolymers, poly(methyl methacrylate–block–methacryloyloxyethyl carbamoyloxy–N-trityl methyl serine) (Py–PMMA–b–PMTS) and poly(N-isopropylacrylamide–block–methacryloyloxyethyl carbamoyloxy–N-trityl methyl serine (Py–PNIPA–b–PMTS) were characterized by 1H (13C) NMR, ultraviolet, FTIR and fluorescence spectroscopy, thermal analysis, differential scanning calorimetry (DSC), atomic force microscopy (AFM), scanning electron microscopy (SEM), and gel permeation chromatography (GPC) measurements. The chemical composition in Py–PMMA–b–PMTS was estimated from the 1H NMR analysis that indicated a ratio of the repeating units of 46:19 (MMA:MTS). For the Py–PNIPA–b–PMTS the composition rate in the copolymer was 61:25 (NIPA:MTS). Quenching of the pyrene species with N,N-diethylaniline, nitrobenzene, nitrophenol, potassium iodide, p-nitrotoluene and tetracyanoquinodimethane (TCNQ) in DMF solution excited at 348nm was evidenced, more efficiently being nitrophenol and TCNQ. In this case, the monomer emission at 388–409nm underwent a significant decrease caused of an electron transfer from the electron-reach photoexcited pyrene molecule to the electron-deficient quenchers. ► Diblock copolymers combine the fluorescence of pyrene–PMMA (PNIPA) with the characteristics of PMTS. ► Such copolymers could be used for nitroderivatives detecting. ► UV/vis and fluorescence measurements give a good correlation for LCST of Py–PNIPA–Br.