  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.

Materials Science