For Materials 1 and 2, irradiation resulted in polymer swelling and the formation of spiked structures ranging from 240 nm to 1.02 µm in height, as measured by stylus profilometry. For Material 1, the exposure time was roughly correlated with the height of the spike (Fig. ), while such control was not observed in the modification of Material 2. Remarkably, the spiked structures in Material 1 and 2 were persistent, as the same morphology was observed by profilometry several months after exposure to the laser light.