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Proceedings Paper

Tailoring the mechanical properties of SU-8/clay nanocomposites: polymer microcantilever fabrication perspective
Author(s): Hao Chen; Vincent Ojijo; Hastings Cele; Trudi Joubert; Sinha Ray Suprakas; Kevin Land
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Paper Abstract

SU-8/Clay nanocomposite is considered as a candidate material for microcantilever sensor fabrication. Organically modified montmorillonite clay nanoparticles are dispersed in the universally used negative photoresist polymer SU-8, for a low cost material, which is also biocompatible. If varying the clay loading of the composite material yields a variation of the Young's modulus, the tailored material stiffness presents an opportunity for fabrication of microcantilevers with tunable sensor sensitivity. With this microcantilever application perspective, mechanical and thermal properties of the material were investigated. SU-8/Clay nanocomposite samples were prepared with clay loadings from 1wt% - 10wt%. Tensile test results show a general trend of increase in composite modulus with an increase in the clay loading up to 7wt%, followed by a small drop at 10wt%. The composite material indeed yields moderate variation of the Young's modulus. It was also found that the thermal degradation peak of the material occurred at 300°C, which is beyond the operating temperature of typical microcantilever sensor applications. The fabrication of a custom designed microcantilever array chip with the SU-8/Clay nanocomposite material was achieved in a class 100 cleanroom, using spin-coating and photolithography microfabrication techniques. The optimization of the process for fabricating microcantilever with the SU-8/Clay nanocomposite material is discussed in this paper. The results of this research are promising for cheaper mass production of low cost disposable, yet sensitive, microcantilever sensor elements, including biosensor applications.

Paper Details

Date Published: 23 June 2014
PDF: 11 pages
Proc. SPIE 9257, Sensors, MEMS and Electro-Optical Systems, 92570B (23 June 2014); doi: 10.1117/12.2066315
Show Author Affiliations
Hao Chen, Council for Scientific and Industrial Research (South Africa)
Vincent Ojijo, Council for Scientific and Industrial Research (South Africa)
Hastings Cele, Council for Scientific and Industrial Research (South Africa)
Trudi Joubert, Council for Scientific and Industrial Research (South Africa)
Sinha Ray Suprakas, Council for Scientific and Industrial Research (South Africa)
Kevin Land, Council for Scientific and Industrial Research (South Africa)

Published in SPIE Proceedings Vol. 9257:
Sensors, MEMS and Electro-Optical Systems
Monuko du Plessis, Editor(s)

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