Numerical Design and Experimental Realization of a PNIPAM-Based Micro Thermosensor

Area of Science:

• Materials Science
• Polymer Science
• Microtechnology

Background:

• Stimuli-responsive polymers are crucial for sensing applications but often lack optimal performance due to simplistic designs.
• Developing advanced sensors requires precise control over material properties and fabrication processes.

Purpose of the Study:

• To create an advanced micro thermosensor using stimuli-responsive polymers with enhanced performance.
• To develop a predictive numerical model for optimizing sensor design and fabrication.

Main Methods:

• Fabrication of a bihydrogel microparticle using stop-flow lithography with poly(N-isopropylacrylamide) (PNIPAM) and poly(ethylene glycol) diacrylate (PEGDA) hydrogels.
• Development of a numerical model simulating mass transfer and polymerization to predict polymer distribution and thermal behavior.
• Experimental validation of the sensor's thermal response and comparison with numerical predictions.

Main Results:

• A micro thermosensor was successfully fabricated, exhibiting a bimetallic strip-like deformation in response to temperature changes.
• The numerical model accurately predicted sensor performance, guiding optimization of geometry and fabrication parameters.
• The optimized sensor demonstrated a working range of 16–55 °C with experimental results closely matching model predictions.

Conclusions:

• The developed numerical model is a valuable tool for designing stimuli-responsive polymer-based microdevices.
• The PNIPAM-based micro thermosensor shows significant potential for bio-related applications and sensing in confined environments due to its biocompatibility and performance.
• This approach can be extended to create other advanced microstructures like shape-evolving microparticles and origami-based microdevices.