Thin films from hydrophilic poly(N,N-dimethyl acrylamide) copolymers as optical indicators for humidity

19th International School on Condensed Matter Physics: Advances in Nanostructured Condensed Matter: Research and Innovations

Lazarova, K.^1 ; Todorova, L.^2 ; Christova, D.^2 ; Vasileva, M.^1 ; Georgiev, R.^1 ; Madjarova, V.^1 ; Babeva, T.^1

Institute of Optical Materials and Technologies Acad. J. Malinowski, Bulgarian Academy of Sciences, Acad. G. Bonchev str., bl. 109, Sofia

1113, Bulgaria^1

Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 103-A, Sofia

1113, Bulgaria^2

关键词: Dimethyl acrylamide;    Extinction coefficients;    In- situ monitoring;    Post deposition annealing;    Redox polymerization;    Reflectance spectrum;    Spin-coating method;    Thickness of the film;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/794/1/012022/pdf
DOI  :  10.1088/1742-6596/794/1/012022

来源: IOP

【 摘 要 】

In the present paper we study thin films from poly(N,N-dimethyl acrylamide)-poly(ethylene oxide) (PDMAA/PEO) copolymers of different composition and structure in order to implement them as sensitive media for optical indicators for humidity. PDMAA/PEO di- and triblock copolymers were synthesized via redox polymerization in aqueous media. Thin films were deposited on silicon substrates by spin coating method using polymers solutions with appropriate concentrations. Refractive index, extinction coefficient and thickness of the films are calculated from reflectance spectra of the films deposited on silicon substrates using non-linear curve fitting method. Sensing properties of the films were tested by films exposure to different humidity levels followed by in-situ monitoring of the changes in the optical properties. The influence of the polymer structure and postdeposition annealing on the optical and sensing properties of the films was investigated. The potential application of selected polymers for optical sensing of humidity were demonstrated and discussed.