Supramolecular Assembly of Conjugated Polymers under Vibrational Strong Coupling

Abstract

Strong coupling plays a significant role in influencing chemical reactions and tuning material properties by modifying the energy landscapes of the systems. Here we study the effect of vibrational strong coupling (VSC) on supramolecular organization. For this purpose, a rigid‐rod conjugated polymer known to form gels was strongly coupled together with its solvent in a microfluidic IR Fabry–Perot cavity. Absorption and fluorescence studies indicate a large modification of the self‐assembly under such cooperative VSC. Electron microscopy confirms that in this case, the supramolecular morphology is totally different from that observed in the absence of strong coupling. In addition, the self‐assembly kinetics are altered and depend on the solvent vibration under VSC. The results are compared to kinetic isotope effects on the self‐assembly to help clarify the role of different parameters under strong coupling. These findings indicate that VSC is a valuable new tool for controlling supramolecular assemblies with broad implications for the molecular and material sciences.

Non‐Polaritonic Effects in Cavity‐Modified Photochemistry

“…Many reports about the effect of vibrational strong coupling on chemical processes have involved comparison of the results from on-and off-resonance samples alongside a cavity-free sample. [25,29,30,47,[61][62][63] These experiments are unlikely to provide a complete picture of the rich variety of optical and chemical processes that occur under the conditions for VSC. It would be helpful if future studies explored a far greater range of cavity thicknesses, so as to help rule out non-polaritonic effects.…”

Direct Observation of Polaritonic Chemistry by Nuclear Magnetic Resonance Spectroscopy

“…Under the right conditions, this interaction gives rise to two hybrid light-matter vibropolaritonic states (VP+ and VP-) along with N-1 dark collective states (DS) resulting from the coupling of N molecules with the optical mode. The formation of these hybrid states, which occurs in the dark, has been shown to alter reaction rates (3)(4)(5)(6)(7)(8)(9)(10), chemical selectivity (11)(12)(13), electrochemical modulation (14), charge transfer equilibria (15) and many other properties such as ionic conductivity (16,17), electrical conductivity (18), solvent polarity (19), crystallization (20) or self-assembly (21,22). Despite the numerous experimental studies of chemistry and properties under VSC and extensive theoretical studies (28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41), a detailed understanding of the underlying processes is still lacking.…”

Manipulating the Self-Assembly of Phenyleneethynylenes under Vibrational Strong Coupling

“…42,43 Modification of the potential energy surfaces, as a result of VSC, can also lead to changes in the intermolecular interactions. 14,15,44 In our earlier work, VSC was shown to transform a conjugated polymer gel into flakes. 15 However, the modification of intermolecular interactions, followed by the selfassembly of simple organic molecules under VSC, has not yet been reported.…”

“…14,15,44 In our earlier work, VSC was shown to transform a conjugated polymer gel into flakes. 15 However, the modification of intermolecular interactions, followed by the selfassembly of simple organic molecules under VSC, has not yet been reported. To investigate such possibility, we have studied two structural isomers of phenyleneethynylene (PE) molecules: linear and V-shaped isomers having different polarity.…”

“…[5][6][7][8][9][10][11][12][13] Very recently, it was reported that light-matter strong coupling can also induce changes in intermolecular interactions affecting the self-assembly of a polymer and the polymorphism of a metal-organic framework. 14,15 Light-matter strong coupling has attracted much attention over the past decade as a means to modify a variety of material properties such as chemical reactivity, transport, ferromagnetism, superconductivity, and non-linear optical response. In particular, vibrational strong coupling (VSC) has been found to have a very large impact on the chemical and physical properties of molecules.…”