On Liquid Water Isothermic Segregation in a Medium of Highly Elastic Hydrophobic Polymers Such as Polymethyl Methacrylate

Abstract Deglassifying the films of plasticized polymethyl methacrylate (PMMA) in heated water causes the spontaneous segregation of water drops of micrometer and larger radius. This process which is accompanied by a change in the film size is impossible in structureless hydrophobia systems. The phenomenon indicates a structural organization of polymer chains, which are responsible for adsorption of a certain amount of molecular water by hydrophobic PMMA. From a thermodynamic standpoint, “structural hydrophily” is of entropic nature and is provided by the micropore generation caused by fluctuations. The micropores are stabilized through the capture of water molecules. When the polymer transforms to the highly elastic state, zones of a dynamically active microporous sponge are formed with the participation of moisture. In these zones, the fluctuation results in the formation and destruction of hydrophobic slits, which ensure the appearance of the water interlayers and drops of critical size that merge into the stable water phase. A thermodynamic model of the process is considered.