Laser swelling of polymer-like materials by nanosecond pulses: modeling

Mechanisms of laser swelling of polymers are considered. A theoretical model for one of the mechanisms is studied in detail. According to this model, swelling is provided by a thermo-elastic wave generated in the material by the laser pulse. The tensile stresses in this wave result in elastic and plastic deformation of polymer in the heated region and formation of a hump structure. The value of the threshold laser pulse fluence for the permanent hump formation and an expression for the permanent hump height are obtained analytically. The model allows us to explain earlier experimental data on laser swelling of PMMA film by UV laser pulses.