以丙醇锆(Zr(OPr)4)为原料,乙酸(HAc)为络合剂,聚乙二醇(PEG200)和聚乙烯吡咯烷酮(PVP)为大分子添加剂,在乙醇体系中成功合成了ZrO2及聚合物掺杂ZrO2溶胶.用旋涂法在K9玻璃基片上制备单层光学增反射膜.借助小角X射线散射和激光动态光散射技术研究胶体的微结构.采用傅里叶变换红外光谱、差示扫描量热分析、X射线衍射分析、原子力显微镜、紫外,可见,近红外透射光谱以及椭偏仪对薄膜的结构和光学性能进行表征.用输出波长为1064nm的强激光,采用“R/1”模式测试薄膜的抗激光损伤性能.研究发现,改变体系中HAc和R0的量,可以方便地调节HAc配合反应和H2O分子亲核取代反应发生的概率,从而调控溶胶的稳定性与微结构.在HAc和H2O量配置适当的情况下,原位引入适量的PEG200和PVP可以明显修饰溶胶.凝胶过程,提高溶胶稳定性,促进胶粒之间相互联结成均匀的网络状结构.与溶胶的微结构密切相关,添加PEG200和PVP的薄膜具有更加平整的表面,而膜层均匀的结构及网络状特征赋予薄膜良好的抗激光损伤性能.添加质量分数为10%PEG200和15%PVP的聚合物掺杂ZrO2薄膜,激光损伤阈值可达24.5J/cm^2(脉冲宽度为1ns);在中心波长λ0处,由反射引起的透射率降低约为2%,显示良好的增反射性能.
A series of ZrO2 and polymer doped-ZrO2 sols have been synthesized by the controlled hydrolysis of zirconium n-propoxide. Acetic acid was used as the chelating agent. Poly(ethylene glycol) (PEG) 200 and polyvinylpyrrolidone(PVP) were introduced to produce the hybrid sols. ZrO2 and the polymer doped-ZrO2 optical thin films were then prepared by spin-coating the stable sols on K9 glass substrates. Effects of various synthetic parameters were studied, on the sol stability, the microstructure of colloidal system, the structural and optical properties of the films, as well as the laser damage resistance. In our reaction systems, both hydrolysis and chelation coexist. The preference for any of the two reactions strongly depends on the system composition and ultimately determines the stability and microstructurc of the colloidal system. Besides, the addition of a proper amount of PEG200 and PVP, which probably acts as the competitive ligands, particle surface protective polymers and structure directive agents, can modify the hydrolysis-condensation process, thus producing more stable, uniform sols with mass fractal structure (fm = 2.33-2.46) and average particle diameter of 19.1123.7 nm. Benefiting from the precursor sol structure, the polymer doped-films exhibit excellent surface planarity and uniform inner structure, which endows the films with good optical property and excellent laser damage resistance. For instance, the hybrid film with 10% PEG200 and 15% PVP (mass fractions) showed a high laser damage threshold of 24.5 J/cm^2(for Ins pulse duration) and a reflectivity increase of about 2% than that of the substrate at wavelength of about 1000 nm.