Portable biomimetic sensor devices for the express control of phenols content in water were developed. The synthetic binding sites mimicking active site of the enzyme tyrosinase were formed in the structure of free-standing molecularly imprinted polymer membranes. Molecularly imprinted polymer membranes with the catalytic activity were obtained by co-polymerization of the complex Cu(II)-catechol-urocanic acid ethyl ester with (tri)ethyleneglycoldimethacrylate, and oligourethaneacrylate. Addition of the elastic component oligourethaneacrylate provided formation of the highly cross-linked polymer with the catalytic activity in a form of thin, flexible, and mechanically stable membrane. High accessibility of the artificial catalytic sites for the interaction with the analyzed phenol molecules was achieved due to addition of linear polymer (polyethyleneglycol Mw 20,000) to the initial monomer mixture before the polymerization. As a result, typical semi-interpenetrating polymer networks (semi-IPNs) were formed. The cross-linked component of the semi-IPN was represented by the highly cross-linked catalytic molecularly imprinted polymer, while the linear one was represented by polyethyleneglycol Mw 20,000. Extraction of the linear polymer from the fully formed semi-IPN resulted in formation of large pores in the membranes' structure. Concentration of phenols in the analyzed samples was detected using universal portable device oxymeter with the oxygen electrode in a close contact with the catalytic molecularly imprinted polymer membrane as a transducer. The detection limit of phenols detection using the developed sensor system based on polymers-biomimics with the optimized composition comprised 0.063 mM, while the linear range of the sensor comprised 0.063-1 mM. The working characteristics of the portable sensor devices were investigated. Storage stability of sensor systems at room temperature comprised 12 months (87%). As compared to traditional methods of phenols detection the developed sensor system is characterized by simplicity of operation, compactness, and low cost.
Nanocomposites derived from a cross-linked melamine-formaldehyde polymer matrix and silver nanoparticles (AgNP) were prepared in situ. An interaction between Ag + ions and AgNP with fragments of the 1,3,5-triazine polymer matrix was established. The mean diameter of the AgNP consisting of nanocrystal aggregates in the nanocomposites did not exceed 60 nm and was independent of the type of silver precursor. The polymer composite nanosystems display strong bactericidal activity.A current trend in the development of polymer composite materials involves the use of nanostructurized components. Special attention has been given to the development of their bactericidal properties [1,2]. In the overwhelming majority of such materials, silver-containing fillers, metallic silver nanodispersions, and silver derivatives are used as the active component [3]. Among the variety of polymers finding use in such materials (polyurethanes, polyethers, polyamides, polyacrylates, and polysiloxanes [2]), considerable promise is shown by melamine-formaldehyde polymers (MFP) possessing valuable properties such as ease of preparation, good physical and mechanical indices, good chemical stability, and good resistance to degradation upon storage and use. However, there have been only very few reports on the preparation and use of polymer composites derived from MFP and silver. Trogolo and Barry [4] obtained a composite by the introduction of a dispersion of a silver-containing zeolite into a solution of a melamine-formaldehyde oligomer (MFO) with subsequent deposition of the reaction mixture onto a prepared surface with hardening at 100-250°C and 3-30 MPa over 10-60 min. Kim [5] has reported that introduction of a dispersion of stabilized silver nanoparticles in amounts up to 3 mass % into a reaction mixture derived from MFO and subsequent hardening also gave a polymer coating having bactericidal activity.MFP structurally-modified by thiourea [6,7] and tetraoxalylethylenediamine [7] yield polymers capable of forming complexes with Ag + ions, thereby permitting the removal of such ions or effect their concentration. However, there is no information in the literature on the complexation activity of the melamine fragments (2,4,6-triamino-1,3,5-triazine) of the MFP matrix although complexes of melamine with Ag + ions are quite well known [8,9].
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