Syntheses of Oligophenylenevinylenes−Polyisoprene Diblock Copolymers and Their Microphase Separation

Abstract

A series of functionalized oligophenylenevinylene (OPV) molecules have been synthesized via an orthogonal approach for the purpose of preparing diblock copolymers. The coupling reaction between the aldehyde-terminated OPVs and a “living” polyisoprene (PI) species leads to the formation of OPV−PI diblock copolymers. TEM results on thin films of four copolymers with the same OPV block but different lengths of the PI blocks clearly show nanophase separation. Alternating strips of OPV- and PI-rich lamella domains were observed under TEM, confirmed by the SAXS experiments on bulk samples. Temperature-dependent SAXS studies also revealed an order−disorder transition at around 128 °C for copolymer 1, which is consistent with the TEM results.

Supramolecular Self‐Assembly of Conjugated Diblock Copolymers

“…Divinylbenzene was purified according to literature procedures. [8,9] Tetrahydrofuran was dried by distillation from sodium metal. Ethylene glycol dimethyl ether and N,N-dimethylformamide were dried by distillation from calcium hydride.…”

“…Oligo-(phenylene vinylene) segments were synthesized according to similar procedures described previously. [8,9] Compound 2 A: Compound 1 (0.8355 g, 0.679 mmol) and KOH (0.183 g, 3.4 mmol) were dissolved in THF (15 mL), and H 2 O (0.6 mL) was added. The resulting solution was refluxed for 12 h and then poured into methanol (100 mL) at room temperature.…”

Patterning with block copolymer thin films

“…Currently, these materials have been reported to self-assemble into a large number of novel structures. Yu and coworkers reported lamellar organization of spun-cast thin films of a rod-coil block copolymer containing oligo(phenylene vinylene) (PPV) derivatives as the rod blocks and polyisoprene or poly(ethylene oxide) as the coil block [85]. Other conjugated rod-coil block copolymers have been seen to assemble into ribbon-like fibrils [86] and non-spherical micelles [87].…”

Self-assembly of rod-coil block copolymers from weakly to moderately segregated regimes

“…Finally, the strong anisotropy of rod-like blocks introduces large conformational asymmetry effects in rod-coil block copolymers which can have a considerable impact on the perturb self-assembled morphologies compared to coil-coil block copolymers [19]. The steadily increasing number of experimental and theoretical studies devoted to rod-coil block copolymers, has been triggered by the considerable advances in the synthetic 380 The European Physical Journal E routes followed to control their synthesis [5,[20][21][22][23][24][25][26][27]. In the present study we have taken advantage of the progress made on synthetic strategies to design rod-coil block copolymers, to synthesize two homologue series of rodcoil block copolymers having, respectively, i) the same π-conjugated rod block, ii) different coil polymers of variable molecular weight.…”