Well-defined second-order nonlinear optical polymers by controlled radical polymerization, via multifunctional macromolecular chain transfer agent: Design, synthesis, and characterizations

• Published in: Polymer (Guilford) Vol. 55; no. 3; pp. 782 - 787
• Main Authors: Roy, Anne-Lise, Bui, Chong, Rau, Ileana, Kajzar, François, Charleux, Bernadette, Save, Maud, Kreher, David, Attias, André-Jean
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 12.02.2014; Elsevier
• Subjects: Applied sciences; Chemical Sciences; Controlled radical polymerization; Exact sciences and technology; Multisegmented polymer; Organic chemistry; Organic polymers; Physicochemistry of polymers; Polymers with particular properties; Preparation, kinetics, thermodynamics, mechanism and catalysts; Second-order nonlinear optical (NLO) polymers; Second-order nonlinear optical (NLO) polymers; Controlled radical polymerization; Multisegmented polymer; Nitro compound; Polymerization modifier; Segmented polymer; Non linear optics; Non linear optical susceptibility; Azo compound; Chain transfer; Optical properties; Interfacial polymerization; Optical material; Trithiocarbonates; Second harmonic generation; Reagent polymer; Experimental study; Sulfur copolymer; Functional polymer; Ester copolymer; Free radical polymerization; Preparation; Styrene; Living copolymer; Ethyleneimine derivative copolymer; Styrene copolymer
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2013.12.059

To address the issue of the aggregation in second-order nonlinear optical (NLO) polymers we developed an approach based on the synthesis of a multifunctional macromolecular chain transfer agent. The controlled monomer insertion polymerization into the main chain by a ‘reversible addition-fragmentation chain transfer’ (RAFT) mechanism allows the spatial arrangement of the NLO chromophores along the polymeric chain in order to obtain sequence-ordered polymers. In a first step, a novel trithiocarbonate based macroinitiator containing the disperse red 19 (DR19) units in the main chain was synthesized by polycondensation; in a second step, this polymeric precursor was applied to the synthesis of a sequentially ordered polymer by controlled insertion radical polymerization of styrene. Size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) data revealed that, (i) for the first time, polystyrenes (PS) bearing DR19 dyes covalently bounded were obtained, and (ii) both the insertion reaction and the length of the polystyrene segments were accurately controlled. Whatever the incorporated dye amount, all the copolymers were soluble in common solvents. Second-order optical nonlinearity in corona-poled thin films was evaluated, and second harmonic coefficients up to 80 pm/V were determined for loading ratio lower than 10 wt-% (DR19/PS). This approach opens up opportunities for the incorporation of more efficient chromophores even in apolar matrices. [Display omitted]