Electric Field Induced Selective Disordering in Lamellar Block Copolymers

Abstract

External electric fields align nanostructured block copolymers by either rotation of grains or nucleation and growth depending on how strongly the chemically distinct block copolymer components are segregated. In close vicinity to the order-disorder transition, theory and simulations suggest a third mechanism: selective disordering. We present a time-resolved small-angle X-ray scattering study that demonstrates how an electric field can indeed selectively disintegrate ill-aligned lamellae in a lyotropic block copolymer solution, while lamellae with interfaces oriented parallel to the applied field prevail. The present study adds an additional mechanism to the experimentally corroborated suite of mechanistic pathways, by which nanostructured block copolymers can align with an electric field. Our results further unveil the benefit of electric field assisted annealing for mitigating orientational disorder and topological defects in block copolymer mesophases, both in close vicinity to the order-disorder transition and well below it.

Lyotropic Liquid Crystal as an Electrolyte Additive for Suppressing Self‐Discharge of Supercapacitors

“…It should be noted that the tested sample was 20 vol% of LLC in the electrolyte. This is because LLC as a kind of liquid crystal exhibits anisotropy and can be aligned in electric field due to the electrorheological effect, [23] leading to increased viscosity of the electrolyte and decreased diffusion rate of ions so that the self-discharge caused by redox shuttles and charge redistribution can be mitigated. The OCP decays for the supercapacitors corresponding to points A, B, C, and D at room temperature are shown in Figure 3 4 at a ratio that leads to the formation of LLC phase is more effective in suppressing the self-discharge rate of the supercapacitors.…”

“…These results indicate that adding LLC to the electrolyte of supercapacitors may effectively suppress their self-discharge rate. This is because LLC as a kind of liquid crystal exhibits anisotropy and can be aligned in electric field due to the electrorheological effect, [23] leading to increased viscosity of the electrolyte and decreased diffusion rate of ions so that the self-discharge caused by redox shuttles and charge redistribution can be mitigated. [21,24] It is worth mentioning that to elucidate how LLC affects the cathode and anode differently, future three-electrode tests are necessary.…”

Tuning the mechanical and dielectric properties of clay‐containing thermoplastic elastomer nanocomposites

“…The morphologies adopted by these nanodomains depend on several parameters such as the affinity between the blocks, their molecular weights and their relative proportions [1,2]. Besides, these morphologies can be easily tuned by different external forces that can be applied either during melt compounding or solvent casting fabrication processes [3][4][5][6][7][8].…”

Influence of substrate interaction and confinement on electric-field-induced transition in symmetric block-copolymer thin films

“…The focus of most numerical studies have either been on mechanism of alignment of ordered domains [33][34][35][36][37] or on order-order transition from one morphology to the other in bulk samples [38][39][40][41][42]. The effect of substrate interaction and confinement have not been investigated thoroughly which could signifi-cantly alter the phase morphologies and critical electric field for transition.…”