飞秒激光辅助超临界流体进行生物医用高分子材料微加工

项目名称： 飞秒激光辅助超临界流体进行生物医用高分子材料微加工

项目编号： No.61275131

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 无线电电子学、电信技术

项目作者： 贾威

作者单位： 天津大学

项目金额： 82万元

中文摘要： 飞秒激光烧蚀高分子材料过程中有剩余热存在和多脉冲热积累效应，所以，加工区边缘（过热）形成热影响区，发生改性，这不但影响加工质量，也影响生物可降解特性，成为激光加工技术应用的瓶颈。超临界流体可以对高分子材料进行氧化分解，因此，可以将激光聚焦在高分子材料与液体交界面上，利用焦点处形成的极端物理条件，使（焦点微区内）液体形成超临界态，以氧化分解方式去除需加工的材料，达到微加工的目的，本并可保持加工区生物可降解特性。由于飞秒激光的脉冲宽度极短、峰值功率极高，在透明液体中，多光子吸收占优势，烧蚀阈值很精确，可以在透明液体内部形成超临界态，因此，将激光强度控制在正好等于或略高于超临界态阈值，可进行低于衍射极限的亚微米加工。从而避免了激光直接加工产生的改性和加工质量问题。本项目旨在系统研究利用高功率高重复率飞秒激光和超临界流体相结合进行生物医用高分子材料微加工的物理过程及其加工工艺。

中文关键词： 飞秒激光；激光加工；高分子材料；；

英文摘要： The residual pulse energy and accumulation behavior occurred under ultrashort pulsed laser ablation in polymer materials. It is shown that heat affected zone may be involved due to superheating, and damage the biodegradable properties and clean micromachining, and has become the last bottleneck of laser micromachining. A method based on supercritical fluid is an effective technique used to decompose organic polymers. So, we could put the organic polymer into a supercritical fluid, then move laser focus to the interface between the organic polymer and supercritical fluid, and drive the liquid in laser focus into supercritical state by the extreme physical condition in laser focus. The organic polymer in laser focus would be decomposed and removed. And the biodegradable properties in the boundary of the laser ablated zone could be maintained. Because of the ultrashort pulsewidth and very high peak intensity of femtosecond laser, multiphoton absorption is dominant in a transparent materials, and the breakdown threshold becomes precise. Only inside the transparent liquid, the breakdown would be achieved. If we manipulate the laser intensity just above the breakdown threshold, sub-diffraction limited structure would be produced. The modified texture would be avoid, and the biodegradable properties would be maintained

英文关键词： femtosecond laser；laser machining；polymeric material；；