Na Moonkyong, Park Hoyyul, Ahn Myeongsang, Lee Hyeonhwa, Chung Ildoo
Advanced Materials & Application Research Laboratory, KERI, Changwon 641-120, Korea.
J Nanosci Nanotechnol. 2010 Oct;10(10):6992-5. doi: 10.1166/jnn.2010.2988.
Organic-inorganic hybrid sols were synthesized from nano silica particles dispersed in water and from organoalkoxysilanes, using the sol-gel reaction. This work focuses on the effects of the three multifunctional organoalkoxysilanes dimethyldimethoxysilane (DMDMS), methyltrimethoxysilane (MTMS), and tetramethoxysilane (TMOS) to form a transparent and high-thermal-resistance coating film. The stability of the hybrid sol was evaluated as a function of the reaction time for 10 d through the variation of the viscosity. The viscosity of the silica/DMDMS and silica/MTMS sol was slightly increased for 10 d. The multifunctional organoalkoxysilanes formed dense silica networks through hydrolysis and condensation reaction, which enhanced the thermal resistance of the coating films. No thermal degradation of the silica/DMDMS sample occurred up to 600 degrees C, and none of the silica/MTMS and silica/TMOS samples occurred either up to 700 degrees C. The organic-inorganic hybrid sols were coated on the glass substrate using a spin-coating procedure. The organic-inorganic hybrid sols formed flat coating films without cracks. The transmittance of the hybrid sol coating films using MTMS and DMDMS was shown to be over 90%. The transmittance of the silica/TMOS sol coating film reacted for 10 d abruptly decreased due to faster gelation. The silica/DMDMS and silica/MTMS hybrid sols formed smooth coating films while the surface roughness of the silica/TMOS coating film markedly increased when the hybrid sol reacted for 10 d. The increase of the surface roughness of the silica/TMOS coating film can be attributed to the degradation of the stability of the hybrid sol and to the loss of transmittance of the coating film. It was confirmed in this study that the use of organic-inorganic hybrid sol can yield transparent and high-thermal-resistance coating films.
采用溶胶-凝胶反应，由分散于水中的纳米二氧化硅颗粒和有机烷氧基硅烷合成了有机-无机杂化溶胶。本工作重点研究了三种多功能有机烷氧基硅烷，即二甲基二甲氧基硅烷（DMDMS）、甲基三甲氧基硅烷（MTMS）和四甲氧基硅烷（TMOS）对形成透明且具有高耐热性涂膜的影响。通过粘度变化，在10天的反应时间内评估了杂化溶胶的稳定性。二氧化硅/DMDMS和二氧化硅/MTMS溶胶的粘度在10天内略有增加。多功能有机烷氧基硅烷通过水解和缩合反应形成致密的二氧化硅网络，增强了涂膜的耐热性。二氧化硅/DMDMS样品在高达600℃时未发生热降解，二氧化硅/MTMS和二氧化硅/TMOS样品在高达700℃时也均未发生热降解。采用旋涂工艺将有机-无机杂化溶胶涂覆在玻璃基板上。有机-无机杂化溶胶形成了无裂纹的平整涂膜。使用MTMS和DMDMS的杂化溶胶涂膜的透光率显示超过90%。由于凝胶化速度更快，反应10天的二氧化硅/TMOS溶胶涂膜的透光率急剧下降。二氧化硅/DMDMS和二氧化硅/MTMS杂化溶胶形成了光滑的涂膜，而当杂化溶胶反应10天时，二氧化硅/TMOS涂膜的表面粗糙度显著增加。二氧化硅/TMOS涂膜表面粗糙度的增加可归因于杂化溶胶稳定性的下降和涂膜透光率的损失。本研究证实，使用有机-无机杂化溶胶可制备出透明且具有高耐热性的涂膜。
