Modeling of biosilicification processes with the use of water-soluble polyampholytes

Polyampholytes containing amino groups at various distances from the backbone have been prepared through the reaction of the maleic anhydride-1-vinyl-2-pyrrolidone alternating copolymer with 1,2-diaminoethane, 1,4-diaminobutane, and 1,6-diaminohexane. The acidic properties of the new polymers and their activity in reaction with silicic acid modeling the biosilicification processes under the action of natural polyampholytes have been studied. It has been established that, in a weakly acidic region (pH 5.5-6), the synthetic polymers do not catalyze the condensation of silicic acid but are involved in reaction with primary silica particles. The efficiency of this interaction increases with approach of the amino group to the backbone because of a higher probability of formation of the tertiary complex with participation of carboxyl, amine, and silanol groups.