要 研究以紫外光光化学反应为基础的在聚甲基丙烯酸甲酯(PMMA)表面区域选择性金属化的方法。 通过对无臭氧紫外光、紫外光+臭氧(UV/O3)、臭氧对PMMA表面亲水化改性效果的对比, 发现仅有UV/O3可有效地使PMMA表面亲水。 表面红外光谱表明, UV/O3对PMMA表面协同作用的结果是在辐照区域生成了羧基等含氧活性基团。 以此含氧活性基团为基础, 经过胺化、氯金酸阴离子交换、NaBH4还原等表面反应, 在UV/O3作用区域形成化学镀所必须的金纳米催化中心, 再将PMMA浸入镀金、镀铜等化学镀浴中, 即可实现PMMA表面的区域金属化。 以打印的菲林片为原始掩膜, 该方法分辨率可达50 μm或更小。 以该法制备了金和铜的薄膜微电极、金膜微电热器等金属微器件, 并表征了它们的物理化学性能。
Poly(methylmethacrylate) (PMMA) has been widely used in the fields of optical instruments, aviation and auto industry, construction industry, advertising and decoration industry due to its optical transparency, low cost, low toxicity, and less fragile property. Recently it has been exploited to fabricate microfluidic chips. Region-selective metallization of PMMA surfaces are frequently required to improve the surface properties of PMMA and to integrate micro metal devices in PMMA microfluidic chips. This article presents our recent study on region-selective metalization of PMMA by means of UV/O3-based surface modification in combination of region-selective electroless plating. Deep UV-lights, ozone, and deep UV-lights in cooperation with ozone were compared with respect to the efficiency of hydrophilization of the PMMA surface. It was observed with water contact angle measurements that only synchronized deep UV and ozone treatment can turn the PMMA surface from hydrophobic to hydrophilic effectively. Attenuated total reflection fourier transform infrared spectra revealed that polar moieties such as carboxyl groups were generated on the UV/O3 treated areas. These polar moieties served as the anchors for further chemical reactions including amination of the carboxyl groups with ethylenediamine, adsorption of chloraurate anion onto the amine groups, and reduction of the Au(III) in the chloraurate anion to Au(0) by borohydride. These reactions led to the formation of the catalysis center of gold nano-particles on the UV-irradiated areas, which is indispensable for region-selective electroless plating. After optimization of the experimental conditions, a novel method for preparation of micro metal devices on PMMA surface has been established. With the printed poly(ethylene terephthalate) (PET) film serv- ing as the primary photo mask, the achievable resolution of the prepared micro metal patterns was 50 pm or less. The depos- ited metal films adhered to the PMMA surface so strongly that they co