Over the last decade I have been pursuing thin bilayer plastic films for use in high-volume, low-cost applications. These films are most frequently encountered in potato chip bags as a laminate of PET and PE plastic. Due to the large, inter-layer difference in thermal expansion coefficient, plastic bimorph films curl much more dramatically with temperature than traditional bimetallic strips. Numerous applications suggest themselves, for example, they might function as a low cost damper to vent hot air out of an attic in the summer, but shut to retain warm air during the winter. Or, convert an entire agricultural field into a cold-frame. Toys are another application, some of which reached the market in 2012.
In addition to responding to their environment, the bimorphs can be laminated to thin film heaters, and triggered electrically.
Below is a survey of our work, aggregated over the last decade. Questions or comments welcome- enjoy!
Patents and Papers
How to leverage high-volume low-cost thin-film food packages as bimorphs for industrial-scale applications.
G. Blonder, "Coffee Bags and Instinctive Materials- the path to ubiquity," in Active Matter, S. Tibbits and L. Kinney, Eds., Cambridge, MA: The MIT Press, to be published Fall 2017.
PHASE CHANGE COMPOSITE BIMORPH
Replacing one layer is a bimorph with a composite contain phase-change material. Instead of the curvature changing smoothly with temperature, the film jumps abruptly at the transition. Useful in actuators and sensors.
Demonstration of a "snap" transition in a plastic bimorph film. The lamination process traps stress in the film, breaking symmetry. The film expands when heated, inverting the disk's curvature but changing the axis of symmetry by 90 degrees.
Demonstration of a non-linear PCBM jump caused by the volume expansion of phase-change inclusions embedded in one layer of the film.
 Later inventions, such as is exemplified by U.S. Pat. No. 6,966,812 to Blonder, entitled Thermally Movable Plastic Devices And Toys, describes a more versatile construction that is responsive to changes in temperature. The Blonder …
US8991026B2 Artificial flower novelty and its method of manufacture with Tucker International LLC