Torrisi L
Dipartimento di Fisica, Università di Messina Ctr, Papardo, S. Agata (ME), Italy.
Biomed Mater Eng. 1994;4(1):17-26.
Thin films of bio-polymers, such as polymethylmetacrylate, polytetrafluoroethylene, polyethylene-terephthalate and polyimide, are efficiently etched in air by UV laser pulses. A different sharp laser fluence threshold for significant etching is measured for each polymer. The thresholds are correlated to the chemical structure and to the wavelength-dependent absorption coefficient of the irradiated polymer. The polymers, having low absorption coefficients, show thresholds of the order of some J/cm2, about one magnitude higher than polymers having high absorption coefficients. Measurements on the polymer etching rates, in terms of removed molecules per eV at the used 347 nm wavelength, and a discussion on the laser-polymer interaction are presented. An interesting application of the laser ablation process to bio-polymers, concerning the ability to realize microfilters for the bio-medical field by irradiating the polymer surface through a perforated metal mask, is discussed.
生物聚合物薄膜，如聚甲基丙烯酸甲酯、聚四氟乙烯、聚对苯二甲酸乙二酯和聚酰亚胺，能被紫外激光脉冲在空气中有效蚀刻。每种聚合物都测得不同的显著蚀刻的尖锐激光能量密度阈值。这些阈值与被辐照聚合物的化学结构以及波长相关的吸收系数有关。吸收系数低的聚合物显示出约为几焦耳每平方厘米的阈值，比吸收系数高的聚合物高出约一个数量级。给出了在所用347纳米波长下以每电子伏特去除的分子数表示的聚合物蚀刻速率的测量结果，并对激光与聚合物的相互作用进行了讨论。讨论了激光烧蚀工艺在生物聚合物方面的一个有趣应用，即通过穿孔金属掩膜辐照聚合物表面来实现生物医学领域微滤器的能力。
