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Diffusion of water into SU-8 microcantilevers
Chuanjun Liu1, Ying Liu, Mordechai Sokuler
1Max-Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
Physical Chemistry Chemical Physics : PCCP
|July 8, 2010
Summary
We developed a method to monitor liquid molecule diffusion in polymers. Cantilever bending reveals water diffusion into SU-8 photoresist, allowing quantitative measurement of diffusion coefficients.
Area of Science:
- Materials Science
- Polymer Science
- Chemical Engineering
Background:
- Monitoring molecular diffusion in polymers is crucial for understanding material degradation and performance.
- Existing methods for measuring diffusion coefficients can be complex or indirect.
Purpose of the Study:
- To present a novel method for monitoring liquid molecule diffusion in polymers.
- To quantitatively determine the diffusion coefficient of water in SU-8 photoresist.
Main Methods:
- A piezoelectric drop generator deposited microdrops of water onto an SU-8 photoresist cantilever.
- Cantilever bending was monitored as a response to water diffusion and polymer swelling.
- One-dimensional and finite element models were used to analyze bending dynamics and calculate diffusion coefficients.
Main Results:
- Cantilever bending was primarily caused by water diffusion into the SU-8 polymer and subsequent swelling.
- Qualitative modeling explained bending during water diffusion.
- Finite element analysis provided quantitative measurement of the water diffusion coefficient in SU-8.
Conclusions:
- Cantilever bending is a sensitive indicator of liquid molecule diffusion in polymers.
- The presented method offers a quantitative approach to determine diffusion coefficients in polymer systems like SU-8.
- This technique has potential applications in material science and polymer characterization.
