Blending Approach Preparation of PVA- g-PMA Films with Embedded "Green" Synthesized Silver Nanoparticles for Acetone Optical Detection

Katerina Lazarova; Darinka Christova; Daniela Karashanova; Biliana Georgieva; Gergana Marovska; Anton Slavov; Tsvetanka Babeva

doi:10.3390/s23062941

Blending Approach Preparation of PVA- g-PMA Films with Embedded "Green" Synthesized Silver Nanoparticles for Acetone Optical Detection

Sensors (Basel). 2023 Mar 8;23(6):2941. doi: 10.3390/s23062941.

Authors

Katerina Lazarova¹, Darinka Christova², Daniela Karashanova¹, Biliana Georgieva¹, Gergana Marovska³, Anton Slavov³, Tsvetanka Babeva¹

Affiliations

¹ Institute of Optical Materials and Technologies "Acad. J. Malinowski", Bulgarian Academy of Sciences, Akad. G. Bonchev Str., bl. 109, 1113 Sofia, Bulgaria.
² Institute of Polymers, Bulgarian Academy of Sciences, Akad. G. Bonchev Str., bl. 103-A, 1113 Sofia, Bulgaria.
³ Department of Organic Chemistry and Inorganic Chemistry, Technological Faculty, University of Food Technologies, 26 Maritza Blvd, 4002 Plovdiv, Bulgaria.

Abstract

The blending approach (also known as the ex-situ approach) was used for the deposition of thin composite films comprising poly(vinyl alcohol-graft-methyl acrylate) (PVA-g-PMA) and silver nanoparticles (AgNPs). Firstly, the copolymer aqueous dispersion was synthesized through the redox polymerization of methyl acrylate (MA) on poly(vinyl alcohol) (PVA) using ammonium cerium (IV) nitrate as the initiator. Then, AgNPs were synthesized through a "green" method using the water extract of lavender based on by-products of the essential oil industry, and then they were blended with the polymer. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to determine nanoparticle size, along with their stability over time in suspension, during the 30-day period. Thin films of the PVA-g-PMA copolymer, with different AgNP volume fractions varying between 0.008 and 0.260%, were deposited via the spin-coating method on Si substrates, and their optical properties were explored. UV-VIS-NIR spectroscopy and non-linear curve fitting were used for the determination of the refractive index, extinction coefficient, and thickness of the films, while photoluminescence measurements at room temperature were conducted for studying the emission of the films. The concentration dependence of film thickness was observed and showed that thickness increased linearly from 31 nm to 75 nm when the nanoparticles' weight content increased from 0.3 wt% to 2.3 wt%. The sensing properties toward acetone vapors were tested in a controlled atmosphere by measuring reflectance spectra before and during exposure to the analyte molecules in the same film spot; the swelling degree of films was calculated and compared to the corresponding undoped samples. It was shown that the concentration of AgNPs of 1.2 wt% in the films is optimal for the enhancement of the sensing response toward acetone. The influence of AgNPs on the films' properties was revealed and discussed.

Keywords: Ag nanoparticles; acetone; green synthesis; lavender; optical sensor; polymers; silver; thin films.

Grants and funding

BG05M2OP001-1.001-0008-C01/CoE "National center of mechatronics and clean technologies"