Diffusion of Anisotropic Colloidal Microparticles Fabricated Using Two‐Photon Lithography. (18th July 2021)

• Record Type: Journal Article
• Authors: Doan, David; Kulikowski, John; Gu, X. Wendy
• Is Part Of: Particle and particle systems characterization. Volume 38:Number 8(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-07-18
• Subjects: brownian motion -- direct laser writing -- screw -- tetrahedrons -- tetrapods; Particles -- Periodicals; 620.43
• DOI: 10.1002/ppsc.202100033
• Languages: English
• ISSNs: 0934-0866

Abstract

Abstract: Polymeric particles with complex shapes are required for biomedical therapies, colloidal self‐assembly, and micro‐robotics. It has been challenging to synthesize particles beyond simple shapes (e.g., spheres, cubes) with high structural accuracy using existing methods. Here, a method for fabricating polymeric microparticles of complex 3D shapes is reported using two‐photon lithography, and dispersing the particles in an aqueous solution on a glass substrate. The fabrication of polyhedrons (e.g., tetrahedron, pyramid), polypods (e.g., tetrapod, hexapod), and other shapes of 5–10 µm in size is demonstrated. Confocal microscopy is used to track the motion of the sphere, tetrahedron, tetrapod, and screw‐shaped particles near the substrate, and determine their translational diffusion coefficients. HYDRO++ is used to simulate the motion of the particles far from the substrate. The influence of particle size and substrate effects on diffusion in the spherical particles is determined and finds that the non‐spherical particles have increased hindrance at the substrate compared to the spherical particles. Abstract : Fabrication of complex, 3D particles is important for applications from colloidal self‐assembly to biomedical therapies. Spheres, tetrahedrons, tetrapods, and screws are fabricated, and their diffusion in an aqueous solution is measured. It is found that diffusion is hindered by the nearby surface, and the amount of hindrance is larger for non‐centrosymmetric shapes.