Rapid bonding of polydimethylsiloxane (PDMS) to various stereolithographically (STL) structurable epoxy resins using photochemically cross-linked intermediary siloxane layers

Elisabeth Wilhelm; Christiane Neumann; Kai Sachsenheimer; Kerstin Länge; Bastian E. Rapp

doi:10.1117/12.2044661

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6 March 2014 Rapid bonding of polydimethylsiloxane (PDMS) to various stereolithographically (STL) structurable epoxy resins using photochemically cross-linked intermediary siloxane layers

Elisabeth Wilhelm, Christiane Neumann, Kai Sachsenheimer, Kerstin Länge, Bastian E. Rapp

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Proceedings Volume 8976, Microfluidics, BioMEMS, and Medical Microsystems XII; 89760A (2014) https://doi.org/10.1117/12.2044661
Event: SPIE MOEMS-MEMS, 2014, San Francisco, California, United States

Abstract

In this paper we present a fast, low cost bonding technology for combining rigid epoxy components with soft membranes made out of polydimethylsiloxane (PDMS). Both materials are commonly used for microfluidic prototyping. Epoxy resins are often applied when rigid channels are required, that will not deform if exposed to high pressure. PDMS, on the other hand, is a flexible material, which allows integration of membrane valves on the chip. However, the integration of pressure driven components, such as membrane valves and pumps, into a completely flexible device leads to pressure losses. In order to build up pressure driven components with maximum energy efficiency a combination of rigid guiding channels and flexible membranes would be advisable. Stereolithographic (STL) structuring would be an ideal fabrication technique for this purpose, because complex 3D-channels structures can easily be fabricated using this technology. Unfortunately, the STL epoxies cannot be bonded using common bonding techniques. For this reason we propose two UV-light based silanization techniques that enable plasma induced bonding of epoxy components. The entire process including silanization and corona discharge bonding can be carried out within half an hour. Average bond strengths up to 350 kPa (depending on the silane) were determined in ISO-conform tensile testing. The applicability of both techniques for microfluidic applications was proven by hydrolytic stability testing lasting more than 40 hours.

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Elisabeth Wilhelm, Christiane Neumann, Kai Sachsenheimer, Kerstin Länge, and Bastian E. Rapp "Rapid bonding of polydimethylsiloxane (PDMS) to various stereolithographically (STL) structurable epoxy resins using photochemically cross-linked intermediary siloxane layers", Proc. SPIE 8976, Microfluidics, BioMEMS, and Medical Microsystems XII, 89760A (6 March 2014); https://doi.org/10.1117/12.2044661

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