Polymer Nanocomposites

Smart Materials Fold into Origami Shapes

The field of smart or active materials includes a wide range of materials that react to some kind of outside stimulus and respond in a useful way. This might involve sensors that respond to temperature changes or the presence of a gas, piezoelectric materials that turn electrical current into mechanical motion and vice versa for energy harvesting or ultrasound, shape memory alloys, or the kinds of materials that fold or unfold as a result of an electric or magnetic field.

Scott Phillips and his group in Chemistry work on stimuli-responsive materials, called autonomous plastics, for shape-shifting and smart biomedical materials, among other applications. Reggie Hamilton's group in Engineering Science and Mechanics study the microstructure and physical behavior of shape memory alloys for actuation, sensing, and damping applications. Along with Todd Palmer in the Applied Research Lab at Penn State, Hamilton won an NSF grant to study 3D printing with Nitinol powder, the temperature based reversible shape memory and super-elastic alloy of nickel and titanium.

Penn State has been a leader in the piezoelectric and ultrasound area of smart materials for several decades and continues to actively engage in research involving piezoelectric materials. The group led by Susan Trolier-McKinstry has developed a piezoelectric thin film on glass for adjusting the mirror for an x-ray space telescope while in orbit (see "Undergraduate Summer Researcher Contributes to Futuristic Space Mirror" in this issue), and, with IBM, is developing a high-speed, low-power piezoelectronic switch/transistor that is theoretically capable of functioning at higher speeds than current CMOS technology at 1/100 the power. As part of a collaboration with North Carolina State University, the McKinstry group is developing technologies to harvest energy from the human body to power wearable sensors. Qiming Zhang, Distinguished professor of electrical engineering, is a world leader in electroactive polymers, an active area of smart materials and systems research.

Read the full news story here Focus on Materials: Smart Materials.