Nanoscale Electromechanics for Interfacial Phenomena

Texas A&M Engineering Experiment Station, College Station TX

Investigators

Abstract

Nanoscale Electromechanics for Interfacial Phenomena NSF Proposal 0301157 PI: James G. Boyd IV KeyWords: Interfacial transport phenomena, electric double layers, Gouy-Chapman theory, liquid electrolytes, dynamics, NEMS, supercapacitors, Atomic Force Microscopy There are four objectives to the proposed research: (1) Develop an interface (2-D) theory for electromechanical phenomena in electrolytes, with an emphasis on electric double layers; (2) Evaluate the usefulness of the theory in applications that are now modeled using the 3-D Gouy-Chapman theory; (3) Derive scaling laws for the dynamics of Nano Electromechanical Systems (NEMS) in liquid electrolytes, including the maximum theoretical energy and power density of nano-structured double layer supercapacitors; and (4) Experimentally characterize the dynamics of NEMS in liquid electrolytes and compare the experiments to theoretical predictions. The deformable electrodes will consist of metallized Atomic Force Microscope (AFM) tips, separated by 0 to 50 nanometers. Force, displacement, electric potential, and electric current will be measured. This research will provide a fundamental understanding of the dynamics of NEMS in liquid electrolytes, including "pull-in" instabilities of parallel-plate capacitors and actuators in the presence of ionic double layers. The environmental impact includes improved supercapacitors, which are necessary to provide high power in electric and hybrid-electric vehicles that reduce greenhouse gases and air pollution. In heavy urban traffic more than half of the total energy consumed is dissipated in the brakes. Therefore regenerative braking, which recovers and stores the kinetic energy that is lost during braking, will be included on electric and hybrid electric vehicles. Supercapacitors can be charged fast enough to absorb regenerative braking power; batteries cannot. Body fluids are 0.2M electrolytes, and this research will enable new applications of NEMS in body fluids, including valves, tweezers, scalpels, automated patch-clamp devices, actuators, optical components, sensors, etc. The outreach program includes two high school students to work in the lab each summer. With help from the Engineering Academic Programs Office, these students will be recruited from schools in the Urban Systemic Initiatives/Programs and Rural Systemic Initiatives. Each of these NSF-sponsored programs has working relationships with the College of Engineering at Texas A&M University.