The effects of alpha irradiation on the optical reflectivity of composite polymers. (February 2022)

• Record Type: Journal Article
• Authors: Chavan, Vivek; Kulkarni, Atul; Lee, Sang-Deok; Kanade, Vinit; Lee, Dongmok; Kim, Hyeong-U; Kim, Do Yoon; Kim, Taesung; Bhoraskar, Sudha; Bhoraskar, V.N.; Hong, Seung-Woo
• Is Part Of: Radiation physics and chemistry. Volume 191(2022)
• Publication Date: 2022-02
• Subjects: Optical reflectivity -- Radiation effects -- Copolymers -- Alpha particle -- Fiber optic -- Reflectance sensor -- Raman spectroscopy; Radiation chemistry -- Periodicals; Radiometry -- Periodicals; Radiation -- Periodicals; Chimie sous rayonnement -- Périodiques; 539.2
• DOI: 10.1016/j.radphyschem.2021.109832
• Languages: English
• ISSNs: 0969-806X

Abstract

Abstract: This paper reports an increase in the optical reflectivity of two kinds of copolymers used in contact lenses, with different proportions of silicon and fluorine derivatives, when irradiated with 4.1 MeV alpha particles from an 241 Am source. The fiber-optic reflectance technique showed that the lens with a higher proportion of silicon and fluorine content and a lower proportion of methyl-methacrylate is more susceptible to alpha radiation. X-Ray photoelectron spectroscopy and Raman spectroscopy have revealed the formation of silicon oxide and carbide species as a result of chain scission and recombination in the 20 μm thick irradiated regions of lens materials. It is presumed that the high (260 eV/nm) linear energy transfer of alpha particles in polymers creates trapped gas "Bubbles", and the observed increase in the optical reflectivity with increased irradiation time is explained on the basis of diffuse reflectance caused by the scattering of light from the hard surfaces of these "Bubbles". Highlights: Polymer composition-dependent radiation-resistant properties investigated. Effect of α-irradiation on optical properties of contact lens studied first time. Highly sensitive fiber-optic-based reflectivity measurement. Surface studies reveal the presence of oxide and carbide with increased roughness. Bubbles formed by gases due to chain scission-increased diffused reflectance.