Combination of Circular PDMS Mold and Gasbag Roller to Replicate Micro/Nano Structures of UV Resin on PC Film
Date Issued
2011
Date
2011
Author(s)
Chuang, Tai-Jung
Abstract
Replicating microstructure by roller imprinting is one of the most effective methods to produce the components with nano micro-structures on surface. However, there are two challenges: how to better prepare the roller mold and how to increase the contact area between roller and substrate. The contact between the rigid roller and the substrate is nearly a line; the brief contact prevent perfect replication at high rolling speed. On the other hand, the conventional method producing the microstructure on the roller mold is done by wrapping the electroplated Ni mold on the roller. Warp and deformation of mold easily occur during rolling imprinting.
In this research, a circular PDMS (polydimethylsiloxane) mold and a gasbag-roller imprinting facility are developed. The gasbag with controlled inner gas pressure is employed to sustain the circular PDMS flexible mold with microstructure. When a external pressure is applied on the shaft of gasbag-roller, the contact area between the roller and the substrate has been increased significantly from original line contact to area contact. This allows ample contact area and time between a gasbag-roller and substrate for the micro-structures on the mold to be completely replicated and cured.
With aid of pressure sensitive films, it is discovered that the combination of the gasbag-roller and the PDMS mold not only increases the contact area between roller and substrate, but also enhances the contact pressure over the contact area. The quality and speed of replication thus can be greatly improved. A V-cut microstructure has been fabricated on the circular PDMS mold by micro-casting, and used for the gasbag-roller sustained circular PDMS mold. Experimental result show that over a large operational window of inner gas and external pressures the replication can be perfect.
The imprinting facility and process have been employed to replicate AAO nanostructures on the PC film for antireflection and hydrophobic effect. The reflection has been droped from 9% in the bare PC film to 6% in the PC film with AAO nanostructures. The contact angle has increase from 86.4 o in the bare PC film to 108.1o in the PC film with AAO nanostructures. Fresnel microstructures are also replicated for the function of light-focusing. The light intensity has increased threefold as measured by the optical power meter. The results prove that an effective replication facility and process has been developed for fast and effective replication of micro- and nano-structures.
Subjects
Circular PDMS mold
Gasbag-roller
UV imprinting
Type
thesis
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