Plants generate motion for activities such as prey capture and sun tracking by modulating the fluid pressure within 10-100 micron diameter structural cells. This pressure modulation is achieved by actively transporting fluid through the cell walls. Essentially these plant structures are highly distributed and redundant hydraulic actuation systems.
The Nastic Materials Program is exploring the development of a new class of active materials that can mimic the ability of plants to generate large strains while still performing a structural function. The impetus for this work is the desire to develop a highly controllable and reversible material system that can generate 10 Megapascals and 20 percent in blocked stress and free strain, respectively. The ultimate goal is the development of plant-inspired actuation systems that possess the power density of conventional hydraulic systems for application in military adaptive or morphing structures.
(from article on Nastic Materials, on darpa.mil)
innovations-report.com
Coupled transport/hyperelastic model for nastic materials - adsabs.harvard.edu
http://www.eng.vt.edu/pdf/upload_files/EE_Darpa686D1.pdf
Virginia Polytechnic Institute
Virginia Tech is a leading research center for nastic materials.
Center for Intelligent Material Systems and Structures - cimss.vt.edu
Take a look at some of their current projects: - cimss.vt.edu/currentprojects.html
http://www.cimss.vt.edu/smartmaterials.html
http://www.newswise.com/articles/view/507278/
http://www.cimss.vt.edu/shapememoryalloy.html
Carbon Fiber Composite Membrane Wing Autonomous Micro-Air-Vehicles - cimss.vt.edu http://www.sagepub.co.uk/journal.aspx?pid=105659
Ionomeric Polymer Transducers