CONTROLLED STRUCTURING OF POLYMER SURFACES BY UV-LASER IRRADIATION

Excimer laser irradiation of polymers is often accompanied by a modification of the surface morphology at the irradiated regions in the form of a regular, roll-like structure. This modification has a great effect on the properties of a polymer, examples of which are given in this paper for several applications in the textile field. A synergetic model of this surface modification is proposed. This model is based on the assumption that the laser pulse leads to the formation of a very thin molten pool of material beneath the ablated layer. Because of the high absorption coefficient and the high energy densities involved the conditions in this thin layer are far from equilibrium and phenomena like self-organizing material convection occur. The model regards blocked stress fields in the fibrous polymer, which are either internal due to the spinning process or applied externally, and released by the high temperatures, as the driving forces of the effect. © 1990.