Abstract
Evaporation experiments of volatile pure droplets both on the flat surfaces and inside the micro wells are carried out in detail for understanding the fundamental effects of microstructure change, with analysis of the contact-angle characteristics, evaporation rates, micro-well structure dimensions and prototype fabrications, and comparison of the distinct results. Designs of the diluted droplets (water/microspheres) deposition on the micro-well surface are introduced along with the non-contact measurement principles of surface profile using a confocal laser system, experimental apparatus setup, and microfabrications and measurement results. Their evolution modes of droplet evaporation on the micro-well surfaces are studied by varying wettability (SU-8 and PDMS) to improve the profile uniformity. Resulting flat meniscus from diluted droplets that contain microspheres in suspension achieves high uniformity (~2.9%) with suitable wettability. Moreover microstructure self-formation and release from structured surface is presented in corporation of droplet and molding operation based on the surface tension of droplet in nature. Concentrated PU polymer droplets are used for many three-dimensional arbitrary-curvatured microstructures. Approximate method based on surface tension (energy) is described and solved for the curvatured shapes after drying as well. Those achieved results can be applied to various manufactures of the microstructures including LCD color filter, ploy-LED, polymer transistors, NDA bio-chips and microlenses.