Micro-heaters embedded in PDMS fabricated using dry peel-off process

• Au micro-heaters embedded in PDMS were fabricated using dry peel-off process.
• Only ∼90 mW was necessary to heat up the micro-heaters to 90 °C.
• We could not observe any degradation of the micro-heaters by thermal stresses.
• Micro-heaters took less than 60 s to reach the target temperature (90 °C).
• The spatial temperature distribution was not significantly varied with substrates.

The present report describes a reliable fabrication method of micro-heaters embedded in polydimethylsiloxane (PDMS), and shows the characterization of the micro-heaters. Metallization of PDMS is achieved using a dry peel-off process which involves modifying the surface properties of the substrate and metal patterns through self-assembled monolayer (SAM) and manually peeling off the PDMS with embedded metal layers. Thus, micro-heaters embedded in PDMS can be fabricated by a simpler and easier way compared to a conventional method (e.g. patterning a conducting composite of PDMS using a razor blade). As a result, Au micro-heaters embedded in PDMS were successfully fabricated without any chemical swelling and contamination. Micro-heaters on a glass substrate were also fabricated for comparison with those embedded in PDMS. For heating up to 90 °C, the micro-heaters embedded in PDMS needed only ∼90 mW compared to those fabricated on the glass substrate needed ∼530 mW. Moreover, we could not observe any degradation of the micro-heaters by thermal stresses that confirmed by repeatability (10 thermal cycle with a range of 25–89 °C) and stability test (20 min at 90 °C). Micro-heaters took less than 60 s to reach the target temperature (90 °C) and spent less than 60 s to drop to room temperature. The spatial temperature distribution was not significantly varied with materials of the substrate (i.e. PDMS or glass).

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