聚丙烯酸和水对中空二氧化硅尺寸和单分散性的影响

Effect of polyacrylic acid and water on size and monodispersity of hollow silica

以聚丙烯酸(PAA)、氨水和水(H2O)反应生成的混合物为模板,模板表面的NH+4催化正硅酸乙酯(TEOS)水解,并缩合形成中空二氧化硅纳米粒子(HSNPs)。通过TEM、激光粒度分析、Zeta电位和紫外吸收等一系列测试,对HSNPs的形貌、粒子尺寸与分布,PAA/NH4OH模板表面ζ电位,以及模板溶液中的游离氨含量进行分析。结果表明,PAA的量能控制模板的尺寸,从而影响HSNPs的尺寸,同时影响HSNPs的尺寸分布。使用不加H2O的模板溶液,当模板乳液中PAA的相对含量为0.2mmol/L时,所得预氨化模板较为均匀,所得HSNPs的平均尺寸约为179.9nm,尺寸分布宽度为5.5nm。随着预氨化阶段加H2O量的增加,模板的尺寸减小,HSNPs的平均尺寸可从179.9nm减小到106.0nm。H2O的添加对获得单分散性良好的HSNPs具有重要作用。当H2O添加量为3mL时,HSNPs的尺寸分布最窄可达1.2nm。

Using the mixture of polyacrylic acid(PAA),ammonia and water(H2O)as template,NH+4on the surface of the template catalyzed the hydrolysis and condensation of tetraethyl orthosilicate(TEOS)to form hollow silica nanoparticles(HSNPs).The morphology,particle size and distribution of HSNPs,theζpotential of PAA/NH4OH template,as well as the content of free ammonia in the template solution were studied by TEM,particle size analysis,zeta potential analysis and UV absorption.The results showed that the amount of PAA determined the size of the template,affected the size of HSNPs and size distribution of HSNPs in the meantime.Using the template solution without H2O,when the relative dosage amount of PAA in the template emulsion was 0.2 mmol/L,the pre-ammoniated template was relatively uniform,and in that case,the average size of the obtained HSNPs was about 179.9 nm and the width of size distribution was 5.5 nm.With the increase of the amount of H2O in the pre-ammoniation stage,the size of the template decreased and the average size of HSNPs was reduced from 179.9 nm to 106.0 nm.The addition of H2O played an important role in preparing HSNPs with good monodispersity.When the amount of H2O was 3 mL,the size distribution of HSNPs was the narrowest of about 1.2 nm.