Phase stability of a reversible supramolecular polymer solution mixed with nanospheres

TL;DR

This paper develops a theoretical framework to analyze the phase stability of mixtures of nanospheres and reversible supramolecular polymers, highlighting the influence of temperature, nanoparticle size, and polymer scission energy on phase behavior.

Contribution

It introduces a generalized free-volume theory incorporating depletion effects specific to reversible supramolecular polymers, providing new insights into their phase stability with nanospheres.

Findings

Fluid-fluid phase stability is sensitive to scission energy and nanoparticle radius.

Phase boundaries can be shifted by temperature changes within a single system.

Stable homogeneous mixtures are limited to low nanoparticle concentrations.

Abstract

Theory is presented for the phase stability of mixtures containing nanospheres and non-adsorbing reversible supramolecular polymers. This was made possible by incorporating the depletion thickness and osmotic pressure of reversible supramolecular polymer chains into generalized free-volume theory, recently developed for investigating the phase behaviour of colloidal spheres mixed with interacting polymers [Adv. Colloid Interface Sci. 143 (2008) 1-47]. It follows that the fluidfluid phase stability region where reversible supramolecular polymer chains can be mixed with nanospheres is sensitive to the energy of scission between the monomers and to the nanoparticle radius. One can then expect the fluidfluid coexistence curves to have a strong dependence on temperature and that shifting of phase boundaries within a single experimental system should be possible by varying the temperature. The calculations reveal the width of the stability region to be rather small. This implies that phase homogeneity of product formulations containing reversible supramolecular polymers is only possible at low nanoparticle concentrations.