On recognition phenomena in polymer–minute particle interactions and pseudo-matrix processes

Abstract

Equations describing equilibria in noncovalent interactions between macromolecules and minute particles were obtained by appropriate modification of theoretical dependences derived previously by statistico-thermodynamical treatment of cooperative noncovalent interactions between long (‘polymer’) and relatively short (‘oligomer’) macromolecules (the term ‘minute’ means that a macromolecule is long enough to cover the surface of more than one particle). The equations predict exponential dependence of polymer–minute particle complexes stability on the particle's surface area, and high selectivity (‘recognition’ phenomena) of the interactions with regard to the size of the particles and structure of both particles and macromolecules. Based on the equations, growth process of a particle in solution of appropriate polymer (termed ‘pseudo-matrix’) was treated theoretically in assumption that mutual recognition (i.e. complexation) of the particle and a macromolecule brings the growth to a stop (the term ‘pseudo-matrix processes’ was proposed recently to define such a processes). It was shown that: (a) at very weak noncovalent polymer–particle interactions, the size of ‘dead’ particles should correspond to ∼1–10 nm in diameter; (b) the size should depend on the interaction energy, temperature, and pseudo-matrix concentration; (c) size distribution of the particles must be very narrow; and (d) in simultaneous presence of two or more macromolecular pseudo-matrices, the size control must be effectuated by that one which is capable to recognize the particles on the earliest stage of their growth. The correspondence of the predictions to experimental data and possible methods of particles’ size control in pseudo-matrix processes are discussed.