The freeze-casting process is one with which bulk materials and entire components of several cubic centimeters in size can be manufactured with ease. The process is based on the solidification of water-based solutions or slurries (suspensions). To freeze-cast a scaffold, a solution or slurry is poured into a mold and then directionally solidified. During freezing, the water solidifies in the form of pure ice crystals, and the polymer that was dissolved and the particles that were suspended in this liquid carrier are concentrated between them. Once frozen, the sample is freeze-dried to sublime the ice-phase and reveal the material scaffold; its architecture is the negative of the ice crystals which templated it. The cell wall material structure is the result of a self-assembly process. Freeze casting or "ice templating" is a relatively inexpensive procedure and provides a means to mimic complex, efficient natural materials with hierarchical designs over several length-scales. This award supports research to build models, basic design principles and tools that will enable a systematic approach for the design and manufacture of freeze-cast hybrid materials with enhanced performance. These new materials will be of benefit to both individuals and the general public at large through applications that range from energy generation and storage to tissue repair and regeneration.
This research program focuses on the fundamental science and modeling-driven design of freeze-cast hybrid materials. An interdisciplinary team with expertise in modeling, experiment and characterization will address current knowledge gaps and analyze the formation and evolution of the ice phase and ice-templated material architectures generated by the freeze casting process in an attempt to uncover basic physicochemical principles and determine fundamental processing-structure-property correlations. The three research goals are to (1) determine the underlying fundamental materials science and establish a realistic model for ice-crystal nucleation and growth on a well-defined substrate (graphene) during freeze casting; (2) uncover processing-structure-property correlations by combining multiscale computational modeling with experimental approaches; and (3) develop predictive models to identify the most promising processing-additive combinations in order to custom-design and optimize structure formation and performance in the model material system.
