School of Chemical, Biological, and Material Engineering, University of Oklahoma, 100 East Boyd St., Norman, OK 73019-1004, USA.
School of Chemical, Biological, and Material Engineering, University of Oklahoma, 100 East Boyd St., Norman, OK 73019-1004, USA.
J Colloid Interface Sci. 2022 Mar;609:158-169. doi: 10.1016/j.jcis.2021.11.160. Epub 2021 Nov 28.
Janus particles (JPs) and surfactants express different behaviors at the oil-water interface under compression. When both are present at the interface, their synergies result in a different collapse mechanism than when present individually depending on the concentration of the JPs and surfactants.
Coarse-grained modeling methods were used to probe the synergies between Janus nanoparticles and nonionic surfactants on the stability of an oil-water interface under compression. When both JPs and surfactants were present, the interface was covered at 0-55% area by JPs and contained surfactants at 0-40% of the interfacial surfactant concentration corresponding to the critical micelle concentration (CMC).
Compression of the interface with only surfactants resulted in the expulsion of surfactant molecules to the water phase once the interfacial concentration of surfactant molecules reached the CMC value. Compression of a Janus particle-laden interface past the closed-packing point led to a buckled interface, so that the total interfacial area remained constant upon further compression. When both surfactants and JPs were present on the interface, JPs still caused buckling, which helped retain the surfactant molecules on the interface. The interface exhibited a higher level of deformation in presence of surfactants. When the surfactant concentration was high, under compression, the surfactants partitioned into the water phase, but the buckling of the interface persisted.
在压缩过程中，Janus 粒子 (JPs) 和表面活性剂在油水界面表现出不同的行为。当两者都存在于界面时，它们的协同作用导致的崩溃机制与单独存在时不同，这取决于 JPs 和表面活性剂的浓度。
使用粗粒化建模方法研究了 Janus 纳米粒子和非离子表面活性剂在压缩下对油水界面稳定性的协同作用。当同时存在 JPs 和表面活性剂时，界面被 JPs 覆盖 0-55%的面积，界面上的表面活性剂浓度含有 0-40%的临界胶束浓度 (CMC) 对应的表面活性剂浓度。
仅含表面活性剂的界面在表面活性剂分子的界面浓度达到 CMC 值时，会将表面活性剂分子挤出到水相。Janus 粒子负载界面的压缩超过紧密堆积点会导致界面弯曲，从而在进一步压缩时保持总界面面积不变。当界面上同时存在表面活性剂和 JPs 时，JPs 仍会导致弯曲，从而有助于保持界面上的表面活性剂分子。在存在表面活性剂的情况下，界面表现出更高的变形水平。当表面活性剂浓度较高时，在压缩下，表面活性剂会分配到水相中，但界面的弯曲仍然存在。
