Nature has made a tremendous diversity of  remarkable inventions, adaptations, and designs that have provided humanity with inspiration for engineering applications, including design of spacecraft and submarines. However, many valuable abilities possessed by organisms have been difficult to replicate because of their complexity. Dr. Ryan Hayward, of the University of Massachusetts, Amherst, focuses on the design of biologically-inspired materials that can change their properties upon demand of the user, or that automatically adapt to changes in their environment. In so doing, Dr. Hayward is able to create new materials that impact our lives in many different capacities while mimicking the abilities of natural organisms.

While Dr. Hayward is motivated by fundamental principles, there are many areas in which his research may have a lasting impact. Dr. Hayward and his team expect their technology to be used to create materials for biomedicine that may allow faster healing, less invasive procedures, or more effective interfaces with man-made devices, materials that save energy by turning optical transmission of windows or enable low-power displays, and consumer products including apparel, packaging, and tactile interfaces that can be made with improved properties and in inexpensive ways. In short, using a combination of new approaches to fabricate materials and basic principles of mechanics and geometry, he and his team are able to yield a unique approach to bioinspired materials. Dr. Hayward's mentorship of future scientists in which he helps design experiments and uses creative solutions for longstanding problems in addition to working at a conceptual level that allows his team to create new hypotheses and approaches, has resulted in advances in engineering that at one time may have seemed impossible.

Current projects include:

• Remarkable Transformations: In one project, Dr. Hayward and his team take advantage of processes of differential expansion or contraction to drive shape changes of structured thin sheets and filaments, a commonly observed strategy in nature (for example, the development of ruffled kale leaves, the opening of pinecones, or the burrowing of certain seeds into the ground). The pattern of expansion or contraction generates stresses within the thin structure that are partially relieved by buckling, leading to remarkable transformations in three-dimensional shape. Dr. Hayward's work has focused on developing new materials that can easily be used to fabricate thin structures with patterns of stress that can be triggered using any number of environmental factors including changes in temperature, humidity, light, pH, or salinity, the application of an electrical or magnetic stimulus, or the introduction of particular chemicals or biomolecules.

• Rapid Reconfigurability: Nature has devised strategies to overcome the relatively slow time-scales associated with fluid transport and muscular actuation using the principle of 'snap-through' transitions. The idea is to prepare a system in a state where it is locally stable, but just on the verge of buckling into a very different configuration. Examples in biology include prey capture by Venus flytraps and hummingbirds, while those in man-made structures include toys such as poppers and slap bracelets. Dr. Hayward has focused on elucidating simple geometric principles that allow he and his team to introduce such snap transitions into a wide variety of structures and material systems, and on fabricating new types of rapidly reconfigurable materials based on these ideas.

• Changing Color: Dr. Hayward has been inspired by the amazing ability of certain animals, notably cephalopods (e.g., squids, octopuses, cuttlefish) to camouflage themselves by changing color. While most colors we see around us rely on the selective absorption or emission of certain wavelengths of light, these organisms also make use of photonic structures that yield color through interference of light. Dr. Hayward and his team have focused on the design of photonic multilayer structures that can be modulated by a variety of stimuli to give rise to changes in color. In addition to their promise for adaptive camouflage, Dr. Hayward anticipates that these materials may have applications in displays and energy-efficient coatings.