Silicas with Polyoxyethylene Branches for Modification of Membranes Based on Microporous Block Copolymers

Abstract

We have synthesized cubic and linear polysiloxanes containing polyoxyethylene branches (ASiP-Cu) using tetraethoxysilane, polyoxyethylene glycol, and copper chloride as precursors; the products are stable to self-condensation. The effect of copper chloride content on the chemical structure of ASiP-Cu has been established. A special study was aimed at defining the modifying effect of ASiP-Cu on the sorption characteristics of membranes based on microporous, optically transparent block copolymers (OBCs). These OBCs were produced using 2,4-toluene diisocyanate and block copolymers of ethylene and propylene oxides. The study demonstrated significantly increased sorption capacity of the modified polymers. On the basis of the modified microporous block copolymers and 1-(2-pyridylazo)-2-naphthol (PAN) analytical reagent, an analytical test system has been developed. Additionally, the modified OBCs have the benefit of high diffusion permeability for molecules of organic dyes and metal ions. It has been shown that the volume of voids and structural features of their internal cavities contribute to the complex formation reaction involving PAN and copper chloride.

Microporous Block Copolymers Modified with Cu(II)-Coordinated Polyethylene Oxide-Substituted Silicas for Analytical Sensors

“…In this study, the OBC was used to prepare analytical test systems, 1-(2-Pyridylazo)-2-naphthol (PAN) was used as an organic chromophore, and water-soluble copper salt was used as an analyte. According to previous studies [42], when modifying OBC using ASiP-Cu, a significant increase in the sorption capacity of the microporous block copolymer was observed. It was also found that the sorption capacity of OBC was also influenced by the method of preparing modifiers and its content in the polymer.…”

“…The reaction solution was stirred on a magnetic stirrer without heating. The procedure for the synthesis of Cu(II)-coordinated polyoxyethylene-substituted silicas is given in [42]. After the complete dissolution of the reagents in toluene, TDI (5.4 g) was introduced into the reaction solution.…”

“…In [42], to improve the microphase separation, OBCs were modified with stable-toself-condensation Cu(II)-coordinated polyoxyethylene-substituted silicas (ASiP-Cu). The synthesis of ASiP was carried out using tetraethoxysilane (TEOS) as the main reagent, polyoxyethylene glycol (PEG) was used to create branches in the structure of the resulting silicas, and copper chloride (CuCl 2 ) was used as a catalyst and complexing agent.…”