Synthesis and Characterization of Poly(methyl acrylate) Grafted from Poly(thiophene) to Form Solid-State Fluorescent Materials

Abstract

This paper describes the synthesis and characterization of graft copolymers having a poly-(thiophene) (PT) backbone with poly(methyl acrylate) (pMA) sidearms. Thiophene monomer containing a protected alcohol group was prepared and polymerized via the McCullough method to yield regioregular PT. The backbone was then functionalized to contain an atom-transfer radical polymerization (ATRP) initiator at approximately 90% of the repeat units as determined through 1 H NMR analysis, yielding 2,5-poly(3-[1-ethyl-2-(2-bromopropionate)]thiophene). From these initiator sites, MA was polymerized to yield well-defined polymer brushes. The addition of the sidearms to the thiophene backbone resulted in twisting of the backbone as a result of steric effects, which caused a decrease in conjugation length of the PT. In the solid state, the sidearms trap the PT in a "solution-like" conformation. In addition, these arms serve to separate PT chains and disrupt the ordered array usually seen in regioregular PT. With a lower conjugation length and isolated PT chains, the material achieved a photoluminescent yield of up to 40% in the solid state.

Polythiophene-g-poly(ethylene glycol) graft copolymers for electroactive scaffolds

“…Within this context, copolymers formed by an all conjugated polythiophene (PTh) backbone and other polymeric graed chains have been prepared to improve the very limited processability and solubility of unsubstituted PTh [e.g. poly(methyl acrylate) 24,25 and polystyrene 26,27 ], to fabricate donor-p-acceptor molecular species [e.g. poly(styrene-gra-C 60 ) 28 ] or to prepare hydrophilic conducting surfaces [e.g.…”

Highly Water‐Soluble Thermally Responsive Poly(thiophene)‐Based Brushes

“…Thin films of 3 and 4 display bathochromic shifts of 21 nm and 8 nm, respectively, relative to their solution counterparts, indicating better structural ordering (increased conjugation length) of the PT backbone in the solid state. [28][29][30] The smaller increase in l max for the film of graft polymer 4 (8 nm) compared to that of the PT macroinitiator 3 (21 nm), versus the solution values, points to the fact that the PNIPAAm chains separate the PT backbones, preventing PT backbonebackbone interactions to some extent. [28] Aqueous solutions of the graft polymer 4 displayed a relatively low-energy l max at ca.…”

“…[25][26][27] Formation of PNIPAAm grafts on the PT macroinitiator 3 to yield 4 was confirmed from 1 H NMR data, as indicated by the presence of a broad NH peak at d = 6.59 ppm and CH peak at d = 3.98 ppm, both associated with the PNIPAAm brushes. [23] Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry evaluation of PNIPAAm chains cleaved from 4 (ester hydrolysis) [28] led to the routine observation of mass spectra characteristic of polymer molecules possessing the NIPAAm repeat unit and molecular weights between 1000 and 5000 amu. The molar mass of 4 was found by GPC to be roughly 2 10 6 .…”

Fluorescent Unimolecular Conjugated Polymeric Micelles for Biological Applications

“…A schematic illustration of PT‐ g ‐PMA constructed by grafting‐from strategy. Reproduced with permission . Copyright 2002, American Chemical Society.…”