Resistive and Capacitive Gamma‑Ray Dosimeters Based On Triggered Depolymerization in Carbon Nanotube Composites

Poster Session: 

A

Presenter: 

Lukas Zeininger

Authors: 

Lukas Zeininger Maggie He Timothy M. Swager

Author Affiliation: 

Department of Chemistry, Massachusetts Institute of Technology

Abstract: 

Poly (olefin sulfone)s (POSs) are 1:1 alternating copolymers of sulfur dioxide and olefin monomers that are synthesized by free radical polymerization of an alkene in liquefied sulfur dioxide. POSs are known to undergo triggered depolymerization into their constituent monomers upon exposure to heat, base, or high energy radiation. We present the development of novel optimized POS structures for the wrapping of nanomaterials, which serve as a platform for the detection, characterization, and dosimetry of ionizing radiation. Our sensory system makes use of carbon nanotubes (CNTs) integrated in an insulating POS polymer matrix that can undergo rapid depolymerization when subjected to gamma irradiation. Disassembly of the polymer matrix results in increased contacts between the carbon nanotubes creating an additional electrical pathway that is readily detectable by changes in resistance and capacitance of our sensor devices. Resistance decreases up to 65% after irradiation demonstrates the high sensitivity of this novel class of gamma-ray sensors. In addition, the detection mechanism was evaluated using a commercial device platform and the sensitivity of our small devices upon incorporation of high atomic number molecular or nanoparticulate components into our polymer matrix was investigated. The ease of fabrication and low power consumption of these small and inexpensive sensor platforms combined with appealing sensitivity parameters establishes the potential of the poly(olefin sulfone)-SWCNT composites to serve as a new transduction material in gamma-ray sensor applications. This method is advantageous over present systems for the detection and dosimetry of ionizing radiation, which suffer from drawbacks including expensive and/or complicated manufacturing, need for operation at low temperatures, or voluminous size.