Asymmetric microparticles and heterogeneous microshells via angled colloidal lithography

This work demonstrated a facile approach to the fabrication of the multifunctional asymmetric microparticles and heterogeneous overlapped microshells with the aid of stepwise angled colloidal lithography (ACL). The two dimensional non-close-packed silica sphere arrays were used as template for the fabrication. With two-step angled vapor deposition, the asymmetric microparticles were fabricated. Altering the lattice spacing, incidence angle and the azimuthal angle controlled the size and shape of the microshells capped on silica beads. The overlapped heterogeneous microshells were obtained by dissolving the silica template. Varying the incidence angle and depositing duration controlled the overlapping proportion and the thickness of the microshells, which determined the rigidity or flexibility of microshells. The asymmetric microparticles were modified with well-defined capping of various materials, typically noble metals, which makes them possible being building blocks for self-assembly and localized surface plasmon resonance (LSPR) sensors/surface-enhanced Raman scattering (SERS) materials. The heterogeneous microshells with unique ringent hollow and overlapping structure have potential application in self-folding/opening microcontainers, template for multistage catalytic membrane reactor and microphotonic devices.