Micropatterns are engraved on the film composite using a CNC blade cutter. The engraved samples are then placed inside a jig to undergo thermal responsiveness testing.
The thermal responsiveness test was conducted using a heat gun and a hot plate.
Thermally Adaptive Micropatterns (2016)
For my research assistantship at the Self-Assembly Lab with Skylar Tibbits, I developed a thermally adaptive polymer film composite with active micropatterns for concept shoes designed for Converse. These shoes featured active materials that responded to temperature changes, helping to cool the body and ventilate moisture inside. The polymer films, with different thermal expansion coefficients, were laminated together to create a material that bends and straightens within a specific temperature range.
I tested various polymer films to identify combinations that activated between 35°C and 40°C. Micropatterns of different designs and sizes were engraved on the films using a vinyl cutter to determine which geometry created the largest openings. A polyester film combined with LDPE exhibited the greatest responsiveness within the target temperature range. I also developed a procedure using a hydraulic press to produce an evenly adhered film composite, as the functionality of the pattern is highly dependent on the quality of adhesion between the films. For the final prototype, a Kapton-LDPE combination was chosen for enhanced durability.
Different polymer combinations, as well as variations in pattern geometry, size, and density, were tested and cataloged to identify the most effective combination.
One of the best-performing combinations was a polyester-LDPE film with cross/asterisk-shaped slits. However, its durability was too flimsy to be applied to the surface of a shoe.
The final shoe prototype, featuring the Kapton-LDPE film, was tested using a heat lamp to evaluate its thermal responsiveness.