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Adsorption layer structure in the system of the ionic block polyamino acid copolymers/SiO2 particles A Physicochemical and engineering aspects

Ostolska, Iwona, Wiśniewska, Małgorzata, Nosal-Wiercińska, Agnieszka, Szabelska, Anna, Gołębiowska, Beata
Colloids and surfaces 2016 v.488 pp. 138-144
adsorbents, adsorption, biopharmaceutical industry, composite polymers, ethylene glycol, medicine, molecular weight, pH, polyethylene glycol, silica, silicon, ultraviolet-visible spectroscopy, water solubility, zeta potential
The solution pH impact on the adsorption process of the block copolymers on the colloidal silica surface was investigated. All polymeric chains consist of the poly(ethylene glycol) (PEG) fragment and the suitable ionic polyamino acid segment (poly-l-lysine or poly-l-aspartic acid). PEG is a biocompatible water-soluble polymer, which is widely used in the biopharmaceutical industry because of its excellent water solubility, chain mobility, and non-immunogenicity. When it comes to polyamino acid block, it is also highly biocompatible, non-toxic, and economic with versatile functional groups such as carboxyl or amino groups. The analyzed substances are characterized by different polymer chain structures but have similar average molecular weight. Adsorption amount was measured with a static method using a UV–vis spectrophotometer. Based on the values obtained from the electrokinetic measurements (the surface charge density and the zeta potential), the interactions between the block copolymer macromolecules and the solid surface were explained. As a result, it was possible to determine the mechanism of compounds binding at the silicon dioxide–aqueous solution interface. It is worth emphasizing that both studied macromolecular compounds and the adsorbent are broadly applied in many branches of industry as well as in medicine.