Surface morphology regulation of colloidal Nanoparticles: A convenient Kinetically-Controlled seeded growth strategy

Except for chemical composition, surface morphology may endue colloidal nanoparticles with special interfacial behaviors, which is highly desired in certain scenarios, for example, ultra-stable Pickering emulsion for pharmaceutical applications where only limited chemicals are allowed. Herein, silica colloidal nanoparticle was chosen as a demo to illustrate a kinetically-controlled seeded growth strategy for the surface morphology regulation of colloidal nanoparticles.

Surface chemical heterogeneity was primarily introduced to the silica seed nanoparticles by a seeded growth process in the presence of mixed silicate moieties with thermodynamical incompatibility. Then a further kinetically-controlled seeded growth step was performed to regulate the surface morphology of silica nanoparticles by promoting the selective condensation of tetraethoxysilane on the hydrophilic microdomains.

Upon reducing the growing rate, tetraethoxysilane hydrolysates tend to condensate on silica microdomains, resulting in the formation of raspberry-like nanoparticles. The generality of the kinetically-controlled seeded growth strategy was validated by its success on differently-sized silica seeds modified with a range of silane coupling agents. This established strategy is facile and effective for massive production of raspberry-like silica colloidal nanoparticles with precisely-designed surface morphology and size, offering an ideal platform for the investigation on the exclusive contribution of morphology to the interfacial behaviors of nanoparticles.