Abstract
The introduction of nanosized fillers into composites with conductive polymers allows them to control physical and chemical characteristics of these polymers. Silica nanoparticles due to its remarkable properties, which include large ratio of surface area to volume, excellent chemical stability, low cost of synthesis, and low toxicity, especially convenient surface modification, have attracted much attention of researchers. Such materials may be as excellent platforms for development of smart sensing systems for numerous applications in analytical chemistry and bioanalysis, in medical diagnostics and therapy, environmental and food analysis, security. It is known that the presence of nanosized silica in the structure of hybrid polymeric composites can not only radically change the structure, but also lead to improved mechanical characteristics, sorption capacity, increase or decrease in specific conductivity. In this work the method of polymerization filling “in situ” was used for preparation of the hybrid composites of polyaniline with nanoparticles of silica modified by titanium (TAC-7) and phosphorus (F-2.1) compounds, studied their morphology, electrical and moisture absorption properties. Influence of the content of inorganic component in composites on their specific conductivity, activation parameters of conductivity and their changes under the action of moisture were studied. It is shown that the filler content of 1–4% increases the electrical conductivity of composites and the incorporation of modified nanoparticles F-2.1 helps stabilize the resistivity of nanocomposites at high humidity. The resistivity change less than 2% was observed throughout the whole range of possible moisture, therefore the obtained modified material can be recommended for using in the resistive sensors operating in the condition of high humidity. Moreover, F-2.1 enhances sensitivity of polymer matrix to hydrogen chloride vapors. So, the possibility of using chemically deposited thin films of polyaniline/modified silica nanocomposite for the optical gas sensors production for various purposes, including monitoring the state of environments in real conditions of atmosphere, is shown.
Highlights
Semiconductor polymers with a system of conjugated electronic bonds are promising materials for electronic technology, since they exhibit interesting optical properties, the ability to convert light energy, have sensitivity to chemical and physical influences (Tsizh et al, 2016; Naveen et al, 2017; Pavase et al, 2018; Cichosz et al, 2018; Liu et al, 2019).One of the most important properties of these materials is their ability to change the resistivity in a wide range of values – from insulators to metals
Formation of hybrid composites of polyaniline with silica was performed using one of the nano-chemical approaches – namely, polymerization filling “in situ”, which involves the formation of composite by oxidative polymerization in the presence of nanosize filler in reaction mixture
It is shown that the silica content of 1–4% causes an increasing of composite conductivity, more over the introduction of silica contributes to the stabilization of the polyaniline resistance at high humidity (ψ>70%)
Summary
Ivan Franko National University of Lviv, Universytetska St., 1, Lviv, 79000, Ukraine. Silica nanoparticles due to its remarkable properties, which include large ratio of surface area to volume, excellent chemical stability, low cost of synthesis, and low toxicity, especially convenient surface modification, have attracted much attention of researchers. Such materials may be as excellent platforms for development of smart sensing systems for numerous applications in analytical chemistry and bioanalysis, in medical diagnostics and therapy, environmental and food analysis, security. Що наявність нанорозмірного кремнезему в складі гібридних полімерних композитів може не тільки радикально змінити їхню структуру, але і поліпшити механічні характеристики, сорбційну ємність, змінити питому електропровідність. Ключові слова: поліанілін, кремнезем, морфологія, нанокомпозит, питомий опір, поглинання вологи, сенсорні властивості
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