热处理温度对静电自组装PDDA/SiO_2光学薄膜的影响

Heat-treatment Effect on PDDA/SiO_2 Optical Thin Film Prepared via Electrostatic Self-assembly Multilayer Method

以正硅酸乙酯(EthylSilicate,TEOS)为原料,乙醇为溶剂,NH3·H2O为催化剂,制备了胶粒带负电荷的SiO2溶胶。在低折射率(1.45)的玻璃基片上用静电自组装(ElectrostaticSelfassemblyMultiplayer,ESAM)法制备了带正电荷的聚电解质聚二烯丙基二甲基氯化铵PDDA与SiO2的有机/无机复合层状薄膜。然后对其进行热处理,研究了不同温度热处理对薄膜结构、组成、折射率、机械强度、激光损伤阈值以及光学性能的影响。得到了经520℃热处理后折射率为1.27、激光损伤阈值为68J/cm2、520nm处的透光率为99.0%、抗机械损伤强度大的SiO2光学增透薄膜。但最大的透光率是400℃热处理后520nm处的透光率为99.2%。

SiO2 colloidal solution was prepared using Si(OC2H5)4 (Ethyl Silicate, TEOS) analytical grade reagents as starting materials, ammonia water as catalyst, ethanol as solvent, the mixed liquor of ethanol and distilled water as dilution. The concentration of sol was 10 mg/mL, the particles of SiO2 in sol was negatively. Polyelectrolyte [Poly(diallyldimethylammonium chloride), PDDA] was positively. The PDDA/SiO2 complex films of 20 bilayers were fabricated on glass substrates via the electrostatic self-assembly multiplayer (ESAM) technique. SiO2 optic anti-reflective thin films were formed by heat-treatment under different temperature lower than 520°C. The micro-structure, composition, refractive index and thickness, anti-scratch intensity, laser damage threshold and light transmittance of the SiO2 films were characterized. The results showed that the anti-scratch intensity, laser damage threshold, light transmittance were further improved after heat-treatment. The high light transmittance attained 99.2% at wavelength 520 nm under 400°C heat-treatment and the laser damage threshold reached 68 J/cm-2 under 500°C heat-treatment.