摘要
以聚苯乙烯微球离心后形成的三维规则排列的胶晶作模板 ,以正硅酸乙酯、水、乙醇和盐酸等配制的溶胶填充微球间的间隙 ,然后原位形成凝胶 ,最后通过焙烧除去微球得到三维规则排列大孔二氧化硅材料 .以苯乙烯为原料 ,过硫酸钾为引发剂 ,在 70℃下搅拌 2 8h后得到含聚苯乙烯微球 (直径约为 6 0 0nm)的母液 .将母液在 90 0～ 10 0 0r/min的转速下离心 12～ 2 4h得到紧密堆积排列的胶晶 .以正硅酸乙酯作为硅源 ,按n(Si(OEt) 4) ∶n(EtOH) ∶n(HCl) ∶n(H2 O) =1∶3 9∶0 3∶1 8制成透明的SiO2 溶胶 .溶胶浓度控制在 0 5～ 1 0mol/L .滴加在胶晶上的溶胶靠毛细管的作用力填充入微球间隙 .重复填充多次 (一般不超过 5次 ) .焙烧在流量为 1L/min的空气中进行 ,升温速度控制在 5℃ /min以下 .在 30 0℃下恒温 5h以除去聚苯乙烯微球 ,在 5 70℃下焙烧 5h .焙烧后的样品表面可观察到五颜六色的彩光 .SEM分析结果表明 ,球形孔 (孔径约 5 0 0nm)大小均匀 ,排列整齐 ,保持了微球的紧密堆积排列结构 .孔与孔之间由小孔窗相互交连 ,孔壁比较充实 ,壁厚约为
Three-dimensionally ordered macroporous silica was successfully synthesized using latex sphere colloid crystal as template and sol of tetraethyl orthosilicate, water, ethanol and hydrochloric acid as filling fluid. The latex spheres (with diameter of about 600 nm) were synthesized using emulsifier-free emulsion polymerization technique. By centrifugalizing the latex spheres mother liquor (900 similar to 1 000 r/min, 12 similar to 24 h), close-packed colloid crystal template can be obtained. The sol was synthesized according to molar ratio of Si(OEt)(4) : EtOH : HCl : H2O = 1 : 3.9 : 0.3 : 1.8. The sol concentration was controlled between 0. 5 mol/L and 1.0 ml/L. The sol filled in the voids among spheres by capillary force, and then transformed into gel in-situ. The latex spheres were removed by calcination ( < 5 degreesC/min; 300 degreesC, 5 h; 570 degreesC, 5 h). The macroporous SiO2 shows a beautiful iridescence in reflected light. SEM images indicated that the pores (with diameter of about 500 nm) arrayed periodically and connected each other by small windows.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2002年第2期179-181,共3页
