Direct fabrication of nano-wrinkled 3D microstructures using fitfully accumulated two-photon polymerization

In this paper, we study the accumulated polymerization effect in the two-photon stereolithography process and its application. In the two-photon stereolithography process, less-polymerized material by insufficient dosing is generally removed by rinse material. The less-polymerized region of a voxel transforms into a fully-polymerized region in the voxel-by-voxel scanning process due to the accumulated dose. The parametric study of the accumulation effect for the widths of a voxel and a line pattern is investigated. Generally, accumulated polymerization from the scanning process has an influence on the increase of the pattern width smoothness of the space between each voxel. At a dose that is smaller than the dose generating a minimum size voxel, stochastic nano-patterns are generated by fitfully accumulated two-photon polymerization. Using the method of fitfully accumulated two-photon polymerization at a small dose, 3D micro-structures with nano-patterns are directly fabricated.