Studies of thermodynamics of micellization and pattern of self-association of decyltrimethylammonium bromide in aqueous solutions at 298.15 K

Micelle Dynamic Reconstruction to Effectively Modulate the Transmission of Smart Windows

Micelles are extremely dynamic equilibrium aggregates. The size and shape of micelles are subject to appreciable structural fluctuations with the introduction of foreign ions, temperature, etc. The highly dynamic character has for a long time hugely attracted the interest of researchers to investigate the mechanism of micellar structure change and the dependence of their optical properties on the structure change. Herein, taking the most common sodium dodecyl sulfate (SDS) as an example, the aggregation behavior of SDS with excess K⁺ and the effect of temperature on the K⁺/SDS mixed system were detailed and systematically investigated by combining with molecular dynamics simulations and experiments. The addition of K⁺ leads to a reconfiguration of the original micelle structure, resulting in a significant change in micelle size from the nanoscale up to the microscale. And simultaneously, temperature can induce a dynamic process of conjugation/deconjugation of K⁺/SDS micelles in the mixed solution, which is manifested macroscopically by the change of transmittance. Finally, a temperature-responsive smart gel was prepared by introducing K⁺/SDS into a polyacrylamide (PAM) gel, which showed an excellent tunable performance in transmittance (ΔT_550 nm = 60.1%, ΔT_808 nm = 42.72%). The designed smart window shows potential applications in room temperature control (Δt = 4.1 °C) and excellent stability over the course of 50 cycles.