Waterborne Colloidal Polymer/Silica Hybrid Dispersions and Their Assembly into Mesoporous Poly(melamine-formaldehyde) Xerogels.
Waterborne Colloidal Polymer/Silica Hybrid Dispersions and Their Assembly into Mesoporous Poly(melamine-formaldehyde) Xerogels.
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DOI：
10.1021/acs.langmuir.5b00990
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发表时间：
2015-07
期刊：
影响因子：
--
通讯作者：
Dana Schwarz;J. Weber
中科院分区：
文献类型：
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作者：
Dana Schwarz;J. Weber
在二氧化硅纳米粒子存在下，低聚（三聚氰胺-甲醛）在水相中的酸催化缩聚导致共存的二氧化硅和聚合物纳米粒子的稳定分散体。该分散体可以加工成中孔干凝胶（SBET ≤ 200 m（2）g（-1）），其孔隙率可以通过蚀刻二氧化硅提高至>400 m（2）g（-1）的比表面积。混合分散体的形成机制和特征对于由其衍生的材料至关重要，并使用多种实验技术（电子和力显微镜、光和X射线散射、超速离心和光谱学）进行详细分析。通过静电去稳定化的分散体到干凝胶的转化进行描述。此外，使用显微镜和孔隙率测定法对所获得的材料的孔隙率和形态进行表征。所选择的合成参数对所获得的性能的影响进行了讨论，并发现（最有趣的是），只有观察到稳定的孔隙率，如果二氧化硅纳米粒子存在于分散体内。
The acid-catalyzed polycondensation of oligo(melamine-formaldehyde) in aqueous phase and in the presence of silica nanoparticles leads to a stable dispersion of coexisting silica and polymer nanoparticles. The dispersion can be processed into mesoporous xerogels (SBET ≈ 200 m(2) g(-1)), whose porosity can be enhanced by etching of silica up to specific surface areas of >400 m(2) g(-1). The formation mechanism and the characteristics of the hybrid dispersion are crucial to the materials derived from it and analyzed in detail using a variety of experimental techniques (electron and force microscopy, light and X-ray scattering, ultracentrifugation, and spectroscopy). The transformation of the dispersion into xerogels by electrostatic destabilization is described. Furthermore, the obtained materials are characterized with regard to their porosity and morphology using microscopy and porosimetry. The impact of selected synthesis parameters on the obtained properties is discussed, and it was found (most interestingly) that stable porosity was only observed if silica nanoparticles were present within the dispersion.