Metal-Filled Polyvinylpyrrolidone Copolymers: Promising Platforms for Creating Sensors

Oleksandr Grytsenko; Ludmila Dulebova; Emil Spišák; Petro Pukach

doi:10.3390/polym15102259

Metal-Filled Polyvinylpyrrolidone Copolymers: Promising Platforms for Creating Sensors

Polymers (Basel). 2023 May 10;15(10):2259. doi: 10.3390/polym15102259.

Authors

Oleksandr Grytsenko¹, Ludmila Dulebova², Emil Spišák², Petro Pukach³

Affiliations

¹ Department of Chemical Technology of Plastics Processing, Lviv Polytechnic National University, 12, St. Bandera Str., 79013 Lviv, Ukraine.
² Department of Technologies, Materials and Computer Aided Production, Technical University of Košice, 74 Mäsiarska, 04001 Košice, Slovakia.
³ Institute of Applied Mathematics and Fundamental Sciences, Lviv Polytechnic National University, 12, St. Bandera Str., 79013 Lviv, Ukraine.

Abstract

This paper presents research results on the properties of composite materials based on cross-linked grafted copolymers of 2-hydroxyethylmethacrylate (HEMA) with polyvinylpyrrolidone (PVP) and their hydrogels filled with finely dispersed metal powders (Zn, Co, Cu). Metal-filled pHEMA-gr-PVP copolymers in the dry state were studied for surface hardness and swelling ability, which was characterized by swelling kinetics curves and water content. Copolymers swollen in water to an equilibrium state were studied for hardness, elasticity, and plasticity. The heat resistance of dry composites was evaluated by the Vicat softening temperature. As a result, materials with a wide range of predetermined properties were obtained, including physico-mechanical properties (surface hardness 240 ÷ 330 MPa, hardness number 0.06 ÷ 2.8 MPa, elasticity number 75 ÷ 90%), electrical properties (specific volume resistance 10² ÷ 10⁸ Ω⋅m), thermophysical properties (Vicat heat resistance 87 ÷ 122 °C), and sorption (swelling degree 0.7 ÷ 1.6 g (H₂O)/g (polymer)) at room temperature. Resistance to the destruction of the polymer matrix was confirmed by the results concerning its behavior in aggressive media such as solutions of alkalis and acids (HCl, H₂SO₄, NaOH), as well as some solvents (ethanol, acetone, benzene, toluene). The obtained composites are characterized by electrical conductivity, which can be adjusted within wide limits depending on the nature and content of the metal filler. The specific electrical resistance of metal-filled pHEMA-gr-PVP copolymers is sensitive to changes in moisture (with a moisture increase from 0 to 50%, ρ_V decreases from 10⁸ to 10² Ω⋅m), temperature (with a temperature change from 20 °C to 175 °C, ρ_V of dry samples decreases by 4.5 times), pH medium (within pH from 2 to 9, the range of ρ_V change is from 2 to 170 kΩ⋅m), load (with a change in compressive stress from 0 kPa to 140 kPa, ρ_V of swollen composites decreases by 2-4 times), and the presence of low molecular weight substances, which is proven by the example involving ethanol and ammonium hydroxide. The established dependencies of the electrical conductivity of metal-filled pHEMA-gr-PVP copolymers and their hydrogels on various factors, in combination with high strength, elastic properties, sorption capacity, and resistance to aggressive media, suggest the potential for further research as a platform for the manufacture of sensors for various purposes.

Keywords: 2-hydroxyethylmethacrylate; composite hydrogels; conductivity; copolymers; hydrogels; metal-filled hydrogels; polyvinylpyrrolidone; sensors.

Grants and funding

This research received no external funding, and the APC was funded by projects APVV-21-0418 and KEGA 036TUKE-4/2021 granted by The Ministry of Education, Science, Research and Sport of the Slovak Republic.