The Gu Group works at the intersection of solid mechanics, materials science and nano-chemistry. We study the mechanical behavior of nanoscale metals and hybrid materials, the effect of strain and crystalline defects on optical nanomaterials, and the self-assembly and 3D printing of nano-architected composites.
Diffusion of Anisotropic Colloidal Microparticles Fabricated Using Two-Photon Lithography
Published in Particle and Particle Systems Characterization in July 2021!
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.