高温水热合成具有超低介电常数的规则介孔氧化硅材料

Hydrothermal Synthesis of Ordered Mesoporous Silicas with Extraordinarily Ultra-low Dielectric Constants

分别以高分子三嵌段共聚物P123(PEO20-PPO70-PEO20)和F127(PEO106-PPO70-PEO106)为模板剂,通过高温水热法制备了具有超低介电常数的规则介孔氧化硅材料(OMSs).当合成温度达到200℃时,得到的产物仍可保持规则的介孔结构.X射线衍射和氮气吸附结果表明,OMSs系列材料具有规则的二维六方或体心立方介孔结构、大的比表面积和孔容及均一的孔径分布.29Si MAS NMR分析表明,OMSs与低温(100℃)合成产物相比具有更高的骨架缩合度,从而具有优异的水热稳定性.由于具有大的孔容和高的骨架缩合度,OMSs表现出了超低的介电常数.以P123为模板剂,200℃下合成的OMS的介电常数可达1.31.OMSs作为一类稳定的超低介电常数材料,对于绝缘材料的发展具有潜在的应用价值.

Ordered mesoporous silica samples with extraordinarily ultra-low dielectric constants （k） were hydrothermally synthesized at different temperatures （150-200 °C ） via soft-templates including amphiphilic triblock polymers of P123 （ PEO20-PPOv0-PEO20 ） and F127 （ PEO106-PPOT0-PEO106 ）. The characterizations of XRD and N2 adsorption-desorption isotherms show that these samples have ordered mesostructure, high BET surface area, large pore volume and uniform pore size. 29 Si MAS NMR spectra show that the samples have much higher silica condensation degree than the ones synthesized at relatively low temperatures. More importantly, these samples exhibit extraordinarily ultra-low dielectric constant （k）. For example, ordered mesoporous silica of SBA-15 synthesized at 200 °C gives k value as low as 1.31, which is interpreted by a collaborative effect of large pore volume with high silica condensation degree. These samples with extraordinarily ultra-low dielectric constants would be potentially important for applications of superior insulators in electronic industry.