Thursday, March 1, 2012
106 Spalding Lab, Hartley Memorial Seminar Room
Chemical Engineering Seminar
New concepts in molecular and energy transport within carbon nanotubes: near infrared sensors, resonant ion channels, and thermopower waves
Michael Strano, Professor, Chemical Engineering, Massachusetts Institute of Technology
Our laboratory has been interested in how 1D electronic materials such as carbon nanotubes can be utilized to illustrate new concepts in molecular transport and energy transfer. In the first example, we predict and demonstrate the concept of thermopower waves for energy generation. Coupling an exothermic chemical reaction with a thermally conductive CNT creates a self-propagating reactive wave driven along its length. We realize such waves in MWNT and show that they produce concomitant electrical pulses of high specific power >7 kW/kg. Such waves of high power density may find uses as unique energy sources. In the second system, we fabricate and study SWNT ion channels for the first time and show that the longest, highest aspect ratio, and smallest diameter synthetic nanopore examined to date, a 500 μm SWNT, demonstrates oscillations in electro-osmotic current at specific ranges of electric field, that are the signatures of coherence resonance, yielding self-generated rhythmic and frequency locked transport. The observed oscillations in the current occur due to a coupling between stochastic pore blocking and a diffusion limitation that develops at the pore mouth during proton transport. Lastly, our laboratory has been interested in how semiconducting single walled carbon nanotubes (SWNT) can be modified such that their fluorescent emission is modulated in response to specific molecules, hence creating a new class of sensor. Such sensors have important advantages, including enhanced optical penetration of tissues in the near infrared, reduced auto-fluorescence, infinite resistance to photobleaching and most recently, single molecule analyte sensitivity. This presentation will review our recent efforts in this space including new platforms for label free protein detection, nitric oxide, H2O2 and the interfacing of sensor arrays to living cells.