[22a-D315-1~6] 3.1 Basic optics and frontier of optics

▲ [22a-D315-2] Photoexcitation in Optical Assembling of Dye-Doped Polystyrene Microparticle at Solution Interfaces

〇(PC)Shuichi Toyouchi¹, Yu-Chia Chang¹, Roger Bresoli-Obach², Johan Hofkens², Hiroshi Masuhara¹ (1.National Yang Ming Chiao Tung Univ., Taiwan, 2.KU Leuven, Belgium)

Keywords:Absorption force, Laser trapping, Colloidal particles

Gaining control on the particle-particle interactions and self-assembled structures is a key milestone for colloidal and material sciences. Currently, different strategies have been described to achieve such control, however, all of them lack the spatiotemporal resolution required at the microscale. In this work, we demonstrate the potential of the optical absorption force coupled with other non-optical forces (e.g., capillary force, dipole-dipole interaction or electrostatic repulsion) at solution interfaces to modify the particle-particle interactions and the structural order of dye-doped particle evolving assemblies at the microscale. Under photoexcitation, the absorption force pushes the particles towards the interface and triggers opposite morphology changes, depending on the physicochemical properties of interface; quick hexagonal close packing-rearrangement and explosive dispersion of assemblies, at air/solution and glass/solution interfaces, respectively. Due to the inherent spatiotemporal properties of light and the electronic transition of materials, the so-far unexplored absorption force is a unique element to control and modify the structural order of particle assemblies at interfaces.