Thermodynamic, Kinetic, and Morphological Aspects of Membrane Formation
This chapter discusses the kinetics and mechanisms of liquid-liquid demixing by nucleation and growth, and liquid-liquid demixing by spinodal decomposition. It deals with solid-liquid demixing by gelation. The chapter also discusses kinetic and morphological aspects of membrane formation. The kinetics and morphological aspects of demixing depend on the particular mechanism of demixing. The chapter reviews types of morphology encountered most often in microfiltration/ultrafiltration membranes. The four most common types of membrane morphology are: closed-cellular, open-cellular, lacy, and nodular. The chapter considers droplet coalescence, phase flow, gel demixing, polymer crystallization, and glass transition. It analyses the basic thermodynamic concepts related to membrane formation. Equilibrium thermodynamics represents a fundamental scientific tool for describing physicochemical interactions among membrane forming components. Thermodynamic analysis can provide important information on the limits of component miscibility and, for unstable or metastable conditions, specify the composition and nature of the segregating phases.