Microporous polymer surfaces prepared by an excimer laser ablation technique.

This paper presents an excimer laser microprocessing method to prepare microporous polymer surfaces. The irradiation of a KrF excimer laser (248 nm) was applied to several polymer films by passing a laser pulse through an optical microscope, resulting in ablative photodecomposition. The control unit was designed to control the fluence of the laser, pulse number, size of irradiated areas, and irradiation micropositioning. The ablation depth linearly increased with an increase in the accumulation of pulses. The chemical composition of the ablated surfaces did not vary with the accumulation of pulses, confirmed by x-ray photoelectron spectroscopy measurements. Excellent structuring quality of ablated micropores was obtained for polyurethane, polyimide, and polycarbonate films. As an application of the ablation technique, polyurethane films were micropored by the excimer laser ablation technique in conjunction with open-cell structured, small diameter grafts under development. In vitro cell ingrowth and compliance on the micropored polyurethane films were examined. Rapid ingrowth was observed on pore sizes of a few microns to several tenths of a micron in diameter. Higher density micropores provided enhanced elastomeric properties.