Interfacial aspects of agrochemical formulations

An important application in agrochemicals is that of controlled-release formulations. Several methods are used for controlled release, of which microcapsules (CS) are probably the most widely used. These are small particles with size range 1-1000 pm consisting of a core material and an outer wall. The latter isolates the core material from the environment and protects it from degradation and interaction with other materials. The core active ingredient is designed to be released in a controlled manner as required. Microencapsulation of agrochemicals is usually carried out by interfacial condensation, in situ polymerization or coacervation, all of which are determined by the interfacial properties. 

It can be seen from the above short discussion that agrochemical formulations are complex multiphase systems and their preparation, stabilization and subsequent application require the application of the basic principles of colloid and interface science and this is the objective of the present part [1, 2]. It will start with a section on surfactants and the physical properties of their solutions. This is followed by a section on the interfacial aspects of agrochemical formulations including adsorption of surfactants and polymeric surfactants at the air/liquid, liquid/liquid and solid/liquid interfaces. The stabilization of dispersions, both electrostatic and steric, is discussed in the next section. The basic principles of colloid and interface science are illustrated in detail by considering emulsion concentrates (EW s) and suspension concentrates (SC s). A summary will be given on microemulsions and controlied release of agrochemical formulations. 

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