Research Project
9201670
Project Summary This Small Business Technology Transfer Phase I project proposes the development and optimization of a commercially viable novel polymer based radiation dosimeter for wide-spread deployment. The radiation dosimeter proposed herein is a disruptive technology with a significant market. Although many commercial radiation dosimeters measure individual radiation load, dose quantification and exposure timing; the value proposition of the device described herein is the equivalent performance with a 10-fold reduction in price. Upon optimization, commercialization, and production the dosimeter will allow the real-time individual radiation exposure. Initial products will target niche markets with higher radiation exposure probability such as nuclear power plant personnel. Further optimization in sensitivity will open broader markets such medical applications (i. e. x-ray technician) and in radiation oncology. Finally, in service to the overall goal of NIEHS to provide sensors for environmental monitoring, the cost and performance of the proposed dosimeter will allow widespread personnel deployment to determine the individual radiation load for a large population. Hence, Seacoast Science, Inc. and Professor Timothy Swager (MIT) jointly propose this dosimeter based on underlying principles/technology developed at MIT (Angewandte Chemie, 2010, 122(1), 99-102). In that initial work, a two-electrode conductive dosimeter was coated with a multi-walled carbon nanotube (MWCNT)/polymer blend; upon exposure to gamma radiation, the measured conductance increased from increased interconnected nanocircuitry. Despite impressive results, the conductive measurement required sensitive research-grade electronics. Furthermore, the initial polymer/MWCNT polymer blends displayed sub- optimum sensitivity. Technical hurdles are addressed in this project: optimizing the polymer/MWCNT sensitivity; use of a more sensitive dosimeter platform; and design/fabrication of an appropriate badge-size readout. Accordingly, during this Phase I project, a series of polyolefin sulfones with side groups selected for optimal polymer/ MWCNT interaction and maximum radiation (gamma) cross sectional area will be synthesized at MIT. These polymers will be combined with different grades of multi-walled carbon nanotubes to produce novel blends. The blends will be coated onto Seacoast Science?s proprietary capacitive sensor platform and appropriate accompanying electronics will be designed and fabricated. The analytical performance of these novel dosimeters will then be determined using the radiation source at MIT. The underlying hypothesis is that the sensor microstructure and the capacitive transducer will result in enhanced sensitivity when combined with the Swager polymer/CNT materials in these radiation dosimeters. Because the radiation-induced depolymerization gives rise to increased CNT-CNT contacts, the distance over which charge can be polarized also dramatically increases. These space charge effects are the largest contributor to a capacitance and will be easily measured at much lower radiation exposures than exposures required to form a percolating conductive network between electrodes. The analytical performance of the dosimeters will be determined by exposure to increasing doses of gamma radiation, the response measured, and the optimal polymer blends selected for further Phase II development.
