Radiation sensitive polyacrylonitrile microfibres doped with PDA nano-particles

The subject of this work are microfibres that are made of polyacrylonitrile (PAN) doped with nano-particles of 10,12-pentacosadiynoic acid (PDA) with a mean hydrodynamic diameter of ca. 22 nm, as measured by dynamic light scattering (DLS). Two kinds of microfibres were obtained from a DMF solution (multifilaments - a bunch of 250 microfibres): glossy (diameter: similar to 11-15 mu m) and lustreless (diameter: similar to 27-31 mu m). The fibres responded to ionising radiation by colour changing from white to dark blue or dark blue-brown thanks to the PDA nano-particles; the colour intensity was related to the absorbed dose of radiation. The chemical changes inside the fibres were followed with the aid of Raman spectroscopy. Reflectance spectrophotometry was chosen for characterisation of the fibres by reflectance [%] versus absorbed dose [Gy] relations, which revealed that the lustreless fibres were more susceptible to irradiation. The fibres responded to high-dose ranges and were saturated at about 8 and 15 kGy, for lustreless and glossy fibres, respectively. The fibres were very stable; they did not change their colour after irradiation within at least 30 days. The dose response of the fibres was independent of the dose rate and the way the dose was delivered: in fractions or non-fractioned. The PAN-PDA fibres were used for flat woven textile preparation to serve as 2D radiation dosimeter. An approach to 2D dose distribution analysis using the PAN-PDA textile samples is presented.