Hojoon Yoon, Baekmin Q. Kim, SeoYoung Choi, EunSuk Lee, Jongmin Q. Kim, KyuHan Kim
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引用次数: 0
Abstract
We present an interfacial assembly strategy for constructing asymmetric multilayered colloidal films through lateral compression of laterally segregated particle microdomains at the air–water interface. These microdomains—composed of polystyrene (PS) and silica (SiO2) particles—serve as lateral templates that direct vertical rearrangement during monolayer collapse. Utilizing hydrophilic PS and SiO2 particles with distinct interfacial adsorption affinities, we demonstrate that depletion interactions and compression-induced instabilities induce domain-selective subduction, a process in which one type of particle domain is driven beneath another. Specifically, more hydrophilic silica domains preferentially collapse and subduct beneath less hydrophilic PS domains, resulting in pronounced vertical asymmetry concentrated at the domain boundaries. Langmuir isotherm analysis and SEM imaging reveal that both the lateral extent of domain segregation and the vertical thickness of the resulting multilayers can be tuned by varying the compression distance and depletant concentration. Lower depletant concentrations reduce depletion pressure, facilitating enhanced particle desorption and enabling the formation of broader and more asymmetric multilayer structures. Importantly, this assembly framework remains effective even when the relative wettability of the particle types is reversed. By introducing sulfonic acid functional groups onto PS, we transform it into a highly hydrophilic species. Adjusting subphase pH to suppress SO3H dissociation allows both particle types to adsorb at the interface. Under acidic conditions, the PS–SO3H particles collapse first and subduct beneath silica domains, producing inverted stratification. This inversion confirms that the subduction-driven assembly is not limited to specific wettability pairings, but instead governed by dynamic interfacial energetics and domain interactions.
期刊介绍:
The Korean Journal of Chemical Engineering provides a global forum for the dissemination of research in chemical engineering. The Journal publishes significant research results obtained in the Asia-Pacific region, and simultaneously introduces recent technical progress made in other areas of the world to this region. Submitted research papers must be of potential industrial significance and specifically concerned with chemical engineering. The editors will give preference to papers having a clearly stated practical scope and applicability in the areas of chemical engineering, and to those where new theoretical concepts are supported by new experimental details. The Journal also regularly publishes featured reviews on emerging and industrially important subjects of chemical engineering as well as selected papers presented at international conferences on the subjects.