Surface morphology control of multifunctional biomimetic silica particles: Interfacial properties and optical effects

Abstract

Hierarchically structured biomimetic particles are functionally tunable yet structurally robust, which are versatile building blocks with a broad range of applications from biological systems to optoelectronic devices. Herein, we propose a facile and effective, scalable strategy to fabricate multifunctional biomimetic silica particles through surface morphology control. The various shapes of biomimetic silica particles possessing the surface structure of lotus leaves, as well as the form of raspberries and tori were readily achieved by varying the ratio of methyltrimethoxysilane and tetraethoxysilane precursors. Subsequent Ostwald ripening resulting from the differences in the reaction rate of dual precursors and thermodynamic stability of the initially formed particles yielded a variety of surface structures. Further, surface wettability can be controlled depending on the peculiar surface morphology of biomimetic silica particles. The biomimetic silica particle with rough and corrugated wrinkles similar to the surface of a lotus leaf afforded excellent superhydrophobicity and oleophobicity, and simultaneously provided intriguing optical properties including soft-focus and near-infrared-blocking effects. Our controlled approach opens a new way to fabricate mutifunctional biomimetic particles with a wide range of potential applications in water-repellent, antigravity water delivery, surface reflection control, and IR blocking materials.