Presentation: 2:00 p.m.
Title: Charge Transport and Global Connectivity in a New Type of Colloidal Multiphase System
Sven H. Behrens (PI), J. Carson Meredith (Co-PI) and Elsa Reichmanis (ChBE)
Capillary foams represent an intriguing and entirely new class of colloidal multiphase systems that pose challenges related to the system characterization at the local and global level. While optical and electron microscopy techniques have been used successfully to gain insight into the local structure, a central hypothesis regarding the global connectivity remains untested so far. In a new collaboration, we propose to prepare the first electrically conducting capillary foams and to leverage their charge transport properties to probe the global foam structure. This first study of any transport properties of capillary foams will also lay the groundwork for future, more comprehensive studies addressing heat transport and flow properties of capillary foams, and for the preparation and characterization of “capillary emulsions” a closely related, but so far only predicted form of (soft) matter.
Presentation: 2:30 p.m.
Title: Creating Chirality: a new family of chiral triply periodic minimal surfaces from interpenetrating labyrinths
Sabetta Matsumoto (PI) and Mohan Srinivasarao (Co-PI)
Triply periodic minimal surfaces are harnessed by nature for a variety of purposes. Mitochondria capitalize upon the interconnected structures for maximizing transport across the membrane. Strikingly, the vibrant colors in the wings butterflies and carapaces of beetles can come from intricate mesostructures formed from minimal surfaces. Intense blues, violets and greens form from nanoscale structures based on the gyroid, diamond surface and Schwarz P-surface. Cell membranes can self assemble such bicontinuous triply periodic minimal surfaces quite easily, and the polymerization of chitin creates an index contrast necessary for such optically active metamaterials. The length scale of periodicity tunes the wavelength of the color. We have created a new family of chiral triply periodic minimal surfaces that has a tunable chiral axis. This surface is based upon two dual interpenetrating labyrinths — the quartz network and its dual, the QZD. The space group, P6₂22, features a three-fold screw axis. By tuning the pitch of this screw axis, the corresponding minimal surfaces gain a tunable chiral pitch. As minimal surfaces readily self-asemble in a variety of systems — lipid membranes, liquid crystals, diblock copolymers, soap films, etc — we hope to fabricate this family of surfaces with controllable optical response.
Presentation: 3:00 p.m.
Title: Conducting Nanocomposites as Bioelectronic Electrode Materials
Meisha L. Shofner (PI) and John R. Reynolds (Co-PI)
Interfacing biological systems, including both internal and external connections to the human body, with electronic devices will yield important advances in health care, commerce and defense. This proposed research seeks to produce functional polymeric materials as flexible and elastic electrodes for bioelectronic applications using controlled phase segregation of conducting and bio-compatible nanoparticles with soft and elastic polymers. Specifically, the proposed project will leverage polymer crystallization as a means of creating electrically conducting nanocomposites through an “assembly exclusion” method to create pathways for transport in the minor phase of the material and robust electronic function. High electrical conductivity and flexibility are favored by this approach since the conducting component is located preferentially at interfaces. Candidate systems containing biocompatible polymers and electrically conducting nanoparticles will be designed, processed, and characterized for structure-property-performance relationships. The proposed teaming of Shofner and Reynolds will provide the needed combination of expertise in materials science composite formation with structural/morphological characterization, electrical and optical properties characterization, and electrochemical utilization of the electrode materials. Results from the proposed work will be used to craft external proposals to DoD and/or industry in order to fully realize devices based on this technology.