Solvent Role in the Self-Assembly of Poly(3-alkylthiophene): A Harmonic Light Scattering Study

Abstract

s are known to self-assemble into well-ordered supramolecular assemblies. The organization influences the optical and electronic properties of these polymers. One way to induce supramolecular self-assembly is by lowering the solvent quality of solubilized poly(3-alkylthiophene) upon the addition of a non-solvent. Recently, the exact mechanism of the supramolecular self-assembly process has been explored for a chloroform/methanol (solvent/non-solvent) system. However, it is not clear how the solvent influences the supramolecular self-assembly mechanism. In this study, poly(3-alkylthiophene) is dissolved in two different solvents and the supramolecular self-assembly is fully explored by combining harmonic light scattering with electronic spectroscopy. Our results indicate that the actual supramolecular self-assembly is very different in both cases and that the choice of solvent has not only a significant influence on the assembly process but also on the structure of the final supramolecular assembly.

Influence of the Irregularity of the Molecular Structure on the Chiral Expression of Poly(fluorene)s

“…THS is very sensitive for the conjugation and aggregation of chromophores. Because the conjugation length hardly changes (see Figure ), any strong increase of THS must originate from aggregate formation with significant phase relations between the polymers present in the aggregate. − Note also, that after aggregation, all signals still change upon the addition of more MeOH, probably due to rearrangements of the polymers in the aggregate.…”

“…We have recently used a new, home-built setup that is able to monitor simultaneously and in situ several optical responses, highly relevant for an aggregation process. A detailed scheme of the setup can be found in the Supporting Information. − The experiment is conducted by starting with a solution of the polymer in CHCl 3 (0.027 mg/mL) and subsequently adding MeOH at a constant rate of 0.8 mL/h. Two excitation sources are used.…”

Nonlinear optical probes of nucleation and crystal growth: recent progress and future prospects

“…observed the different steps of the self-assembly process in unprecedented detail. [63][64][65] In a first study, regioregular P3AT polymer aggregation was initiated either by lowering the quality of the solvent (chloroform) by addition of a non-solvent (methanol), or by decreasing the temperature when dissolved in hexanol. Upon addition of nonsolvent, self-assembly into micro-crystalline aggregates was triggered at a threshold concentration of 33% (v/v) methanol.…”

“…In a third study, the effect of the solvent on the self-assembly process of the P3AT system has been investigated as well, by using thiophene and tetrahydrofuran (THF) as solvent with methanol as the non-solvent. 65 For the thiophene system a three-step process occurred, from the pre-organization of polymers and solvent into clusters, through a reorganization of an intermediate structure which is not fully assembled yet, to the final structure. In THF an even different assembly process was witnessed.…”

Ordered‐Structure‐Induced Electrochemical Post‐Functionalization of Poly(3‐(2‐ethylhexyl)thiophene)

“…In this context, changing simple parameters such as the solvent used to prepare a film, [10][11][12] the film preparation protocol, [13,14] and the post-treatment technique [15][16][17][18][19] leads to 𝜋-conjugated polymer films with various structures. Among these methods, because the solvents used to prepare films affect the alignment and aggregation of the polymer main chains both in solution and in the solid state, [20][21][22] changing the solvent is the most straightforward approach to modifying the film structure. As a result, the electronic properties of 𝜋-conjugated polymer films can be controlled through the use of different solvents for film preparation.…”