Hansenparameterne

Hansenparameters are a set of three values used to characterize the surface energy of a solid. Developed by Charles M. Hansen, these parameters are commonly used in polymer science and surface chemistry to predict the compatibility of different materials and to design coatings and adhesives. The three parameters are: dispersive, polar, and hydrogen bonding components of the surface energy.

The dispersive component, denoted by $\delta_D$, represents the contributions to surface energy arising from van der Waals forces, specifically London dispersion forces. This component is present in all materials. The polar component, denoted by $\delta_P$, accounts for the surface energy contributions from permanent dipole-dipole interactions between polar groups on the surface. The hydrogen bonding component, denoted by $\delta_H$, quantifies the contributions from hydrogen bonding interactions, which occur when a hydrogen atom is bonded to a highly electronegative atom like oxygen, nitrogen, or fluorine.

These parameters are determined experimentally, often through techniques like contact angle measurements on a series of liquids with known Hansen parameters. By measuring the contact angle of these liquids on the solid surface, a set of equations can be solved to determine the unknown Hansen parameters of the solid. The values are typically expressed in units of pressure, such as megapascals (MPa).

Hansen parameters are widely applied in predicting miscibility of polymers, selecting solvents for dissolving or swelling polymers, and designing surface treatments to improve adhesion between dissimilar materials. Materials with similar Hansen parameters are more likely to be compatible, meaning they will mix well or adhere strongly. This predictive capability makes Hansen parameters a valuable tool in material selection and formulation across various industries.