Mauser Tatjana, Déjugnat Christophe, Möhwald Helmuth, Sukhorukov Gleb B
Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14424 Potsdam, Germany.
Langmuir. 2006 Jun 20;22(13):5888-93. doi: 10.1021/la060088f.
Hollow microcapsules composed of the weak polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(methacrylic acid) (PMA) are templated on silicon oxide particles using the layer-by-layer adsorption. The colloidal template is removed with a buffer system of hydrofluoric acid and ammonium fluoride. With this buffer system, the template can be dissolved in mild pH conditions, where the polymeric layers are still stable. The morphology and the thickness of the resulting capsules are investigated with atomic force microscopy. The resulting hollow capsules show pH-dependent properties. The shells are stable over a broad pH range and swell and immediately dissolve for pH values below 2.3 and above 11. If the molecular weight of the poly(methacrylic acid) is increased, the enhanced entanglement of the polymers results in a reversible swelling of the capsules at low and at high pH. The swelling degree is probed with confocal laser scanning microscopy. In addition to the pH-dependent size variations, the different ionization degree of poly(methacrylic acid) as a function of pH is used for the selective binding of calcium ions.
由弱聚电解质聚（烯丙胺盐酸盐）（PAH）和聚（甲基丙烯酸）（PMA）组成的中空微胶囊通过层层吸附法以氧化硅颗粒为模板制备。使用氢氟酸和氟化铵缓冲体系去除胶体模板。利用该缓冲体系，模板可在温和的pH条件下溶解，而聚合物层仍保持稳定。用原子力显微镜研究所得胶囊的形态和厚度。所得中空胶囊表现出pH依赖性特性。壳在较宽的pH范围内稳定，对于pH值低于2.3和高于11的情况会膨胀并立即溶解。如果聚（甲基丙烯酸）的分子量增加，聚合物增强的缠结会导致胶囊在低pH和高pH下发生可逆膨胀。用共聚焦激光扫描显微镜探测膨胀程度。除了pH依赖性尺寸变化外，聚（甲基丙烯酸）随pH变化的不同电离程度用于钙离子的选择性结合。
