An Optimized Methodology to Achieve Irreversible Bonding between PDMS and Polyimides for Biomedical Sensors

Polyimide (PI) and polydimethylsiloxane (PDMS) are widely used materials in biomedical sensor development. The hydrophobic property of PDMS makes it difficult to bind with other materials, such as PI, which is commonly used in sensor applications. This paper employs the chemical functionalization of the PDMS and PI surfaces via epoxy-thiol click chemistry to achieve irreversible bonding. The bonding strength between the PDMS and PI is tested using a peel-off test method where adhesive and cohesive failures are observed. To demonstrate the importance of strong bonding, a wireless pressure sensor is developed. The sensor is tested for cyclic pressures over 1 million cycles with no evidence of bonding failures. This irreversible bonding can improve sensor integrity, reliability, and stability, especially for biomedical applications.