Cyclic Block Copolymer Microchannel Fabrication and Sealing for Microfluidics Applications

High mechanical rigidity, chemical resistance, and ultraviolet-visible light transmissivity of thermoplastics are attractive characteristics in microfluidics because various biomedical microfluidic devices require solvent, acid, or base manipulation, and optical observation or detection. The cyclic block copolymer (CBC) is a new class of thermoplastics with excellent optical properties, low water absorption, favorable chemical resistance, and low density, which make it ideal for use in polymer microfluidic applications. In the polymer microfabrication process, front-end microchannel fabrication and post-end bonding are critical steps that determine the success of polymer microfluidic devices. In this study, for the first time, we verified the performance of CBC created through front-end microchannel fabrication by applying hot embossing and post-end sealing and bonding, and using thermal fusion and ultraviolet (UV)/ozone surface-assist bonding methods. Two grades of CBC were evaluated and compared with two commonly used cyclic olefin polymers, cyclic olefin copolymers (COC), and cyclic olefin polymers (COP). The results indicated that CBCs provided favorable pattern transfer (>99%) efficiency and high bonding strength in microchannel fabrication and bonding procedures, which is ideal for use in microfluidics.

Fabrication Multi-Layer Polymer Microstructures by X-Ray Lithography with Alignment

Poly(methyl methacrylate)(PMMA) and Poly L-lactic acid (PLLA) are transparent and they are suitable for optical purposes. The multi-layer polymer microfabrication can be applied for a large displacement actuator and precision sensors. A new method is intruduced to generate the multi-layer polymers microstructures by X-ray lithography with alignment. The function of X-ray on polymer materials are breaking the polymer main chain and generating intermediates which can be degraded further and finally dissolved by the solvent interaction. The method for polymer micromachining by using X-ray lithography with alignment for fabrication multi-layer micro polymer structures is confirmed experimentatively.