The microelectronics revolution sparked by the invention and the very-large-scale integration of transistors has affected almost every aspect of our daily lives. As the 50-year-old Moore's law is approaching its limits, scientists are now turning to light as the information carrier. Unfortunately, our ability to control light in nanoscopic volumes is in many ways in its infancy, compared with how we can manipulate electrons. A new class of optical materials known as photonic crystals may hold the key to continued progress towards all-optical integrated circuits. However, traditional nanomanufacturing technologies for producing photonic crystals with three-dimensionally ordered nanostructures suffer from low throughput, small sample areas, and high cost. By integrating a simple, fast, and inexpensive colloidal self-assembly methodology with a new type of shape memory polymer, this project will explore a novel scalable nanomanufacturing approach for wafer-scale production of photonic crystals with reconfigurable optical properties. This interdisciplinary research will be closely integrated into curriculum development, new demonstration module design, and training of underrepresented high school and undergraduate students through a few successful programs at the university.
Although various colloidal self-assembly technologies have been developed, most of these bottom-up approaches are only favorable for low volume, laboratory-scale production of photonic crystals. Moreover, self-assembled photonic crystals with fixed microstructures are only appropriate for fabricating passive nanooptical devices. Smart shape memory polymers that can memorize and recover their permanent shapes from structurally stable temporary sates are promising for developing active photonic crystal devices. Unfortunately, most of the existing shape memory polymers are thermoresponsive, and they suffer from heat-demanding shape memory cycles. The research team aims to conduct simultaneous experimental and theoretical investigations to address the key scientific and engineering barriers faced by the current colloidal self-assembly and shape memory polymer technologies. In-situ nanoscopic mechanical and mechanochromic tests, along with multiphysics mechanical finite element analysis simulations will facilitate the basic understanding of the unusual shape recovery mechanisms of the new type of shape memory polymer that enables unconventional all-room-temperature shape memory cycles. The stimuli-responsive microstructure-optical property relationship of the self-assembled photonic crystals will be elucidated by optical characterization and finite element optical simulations. Large-area macroporous polymer photonic crystals with optimal crystal structures and multiple memorizable optical states will be fabricated by the scalable bottom-up nanomanufacturing technology.
