Impact of Tailored Gamma Irradiation on Pore Size and Particle Size of   Poly[Ethylene Oxide]Films: Correlation with Molecular Weight Distribution   andMicrostructural Study
  The structure and morphology of polymers are significantly altered upon exposure to high energy gamma irradiation. The present investigation reports the influence of such irradiation of doses in the range of 1 - 30 kGy on the particle size of Poly (Ethylene Oxide) [PEO] powder along with its correlation with molecular weight distribution. Pore-size distribution and overall porosity of the synthesized films prepared with irradiated and unirradiated PEO powder is also reported. The particle size of both unirradiated and irradiated PEO powders is found be in the range of 0.01 - 1000 micrometer. It is known that, variation in irradiation dose either generates particles of lower dimension through bond breakage i.e scission or higher dimension through cross-linkage. PEO films exhibit strong dependence of irradiation effect on pore size distribution and porosity. PEO films synthesized using both unirradiated and irradiated powders exhibit pore dimension in the range of 20 - 500 nm. The overall porosity of PEO films studied through BET adsorption technique initially increases with dose upto 3 kGy followed by linear decrease upto 30 kGy. Films cast with unirradiated PEO powder show multimodal pore size distribution, but perturbation with irradiation changes the modality to uni-or bimodal nature. The mentioned outcome of irradiation viz. particle and pore size variation is also correlated with PEO microstructures.The article demonstrates that, selective irradiation is capable of tailoring the pore-size within a definite regime thereby reducing the multimodal trait. The reported study may be relevant towards applications such as catalysis, sensing and filtration, where pore size distribution plays a crucial role. 
Madhumita Mukhopadhyay, Mou Saha, Ruma Ray and Sujata Tarafdar
cond-mat.mtrl-sci