Colloidal particles or polymers in a liquid medium generally make soft mater. They usually result in (micro)phase separation and gets unmixed into coexisting phases which varies in composition, structure, and properties for certain compositions. Several theories were put forth to forecast the behavior of soft matter system which is generally made up of colloidal mixtures and block copolymers which are useful in products as coatings, pharmaceuticals and food.
Colloidal particles and polymers are the constituents for the fabrication of novel materials (soft matter) which are basically industrial products like paint, mayonnaise, tooth paste and natural systems like clay, blood and living cells. On the basis of the concentration of colloidal or polymeric components, a fluid or a (liquid) crystal phase is accepted. Interactions between the particles of various sizes or shapes or in solutions of block copolymers in a colloidal dispersion induces phase separation which makes the system non-homogenous and separates into coexisting phases with various compositions. It is required to avoid phase separation for many applications while in some it is a required effect to separate elements by phase transition or by stratification.
To learn more about phase behaviour of colloidal mixture, the stability regions of various types of (coexisting) phases for colloidal mixtures for a wide range of size ratios, shape parameters, and concentrations were mapped. Experiments and computer simulations carried out by collaborators were in close proximity with his model predictions. The possibility of separating into five various coexisting phases in a simple dispersion containing only two types of hard particles were the various phenomena disclosed from the theory later on.
Lattice model:
Block copolymers can spontaneously order into macroscopic phases with periodic domains in the nanometer scale. The control of size and shape of these domains by solvents which are used to make block copolymers with specific electrical or optical properties was shown using lattice model. The surface affinity of block copolymer surface modifiers in coating formulations relevant for the automotive industry is affected by drying was also shown. The distribution of block copolymers over the bulk and the surface can diverge the wet coating formulation and the cured coating was disclosed by the results.
An efficient method to know how some parameters affect phase transitions so it can be used to lead the experimental and computational work was shown by the theoretical model. Hence this research is a major step in understanding and knowing the use of colloidal mixtures and block copolymers which helps the design of soft matter systems with desired properties.
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By Sanika Mungekar
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