Polymer foam-based piezoelectric materials and method of manufacture
View Patent ↗Thermally stable piezoelectric polymer foams (ferroelectrets) with high piezoelectric activity for sensing and actuation. The invention further includes a method of fabricating such foams in an environmentally friendly manner.
1. A multilayer polymer ferroelectret, comprising:
a metallized polymer top layer;
a first patterned polymer layer comprising a plurality of cavities separated by supporting structures;
a central non-metallized polymer layer;
a second patterned polymer layer comprising a plurality of cavities separated by supporting structures, the cavities of the second patterned layer positioned in a horizontal offset from the cavities of the first patterned layer;
a metallized polymer bottom layer; and
positive electric charges and negative electric charges positioned apart from one another across the cavities.
2. The ferroelectret of claim 1 , wherein an amount of the offset is approximately equal to half of a width of the cavities.
3. The ferroelectret of claim 1 , wherein the polymer is selected from cyclo-olefin copolymer, cyclic-olefin polymer, polypropylene, polyethylene naphthalene, polyethylene terephthalate, fluorinated ethylene propylene, polytetrafluoroethylene, polyethylene, polyetherimide, and mixtures thereof.
4. The method of claim 1 , wherein the polymer is a polymer foam.
5. The method of claim 1 , wherein the polymer layers are at least partially saturated with carbon dioxide.