One-Step Fabrication of Thermally Stable TiO₂/SiO₂ Nanocomposite Microspheres by Evaporation-Induced Self-Assembly

Abstract

Micrometric grains of anisotropic morphology have been achieved by evaporation-induced self-assembly of silica nanoparticles. The roles of polymer concentration and its molecular weight in controlling the buckling behavior of drying droplets during assembly have been investigated. Buckled doughnut grains have been observed in the case of only silica colloid. Such buckling of the drying droplet could be arrested by attaching poly(ethylene glycol) on the silica surface. The nature of buckling in the case of only silica as well as modified silica colloids has been explained in terms of theory of homogeneous elastic shell under capillary pressure. However, it has been observed that colloids, modified by polymer with relatively large molecular weight, gives rise to buckyball-type grains at higher concentration and could not be explained by the above theory. It has been demonstrated that the shell formed during drying of colloidal droplet in the presence of polymer becomes inhomogeneous due to the presence of soft polymer rich zones on the shell that act as buckling centers, resulting in buckyball-type grains.

Enhanced photocatalytic activities of TiO2–SiO2 nanohybrids immobilized on cement-based materials for dye degradation

“…This result points out that the addition of SiO 2 on a TiO 2 particle decreased the crystallinity by inhibiting the growth of the titania particle. It is also confirmed that the titania-silica mixture has high thermal stability that made it possible to calcine these particles at a higher temperature without forming the rutile phase [51,52]. In our research, the calcination temperature for nano-TiO 2 and nano-TiO 2 -SiO 2 were 673 and 723 K, respectively, and an anatase phase was identified for both of them (Fig.…”

The Influence of Feedstock and Process Variables on the Encapsulation of Drug Suspensions by Spray‐Drying in Fast Drying Regime: The Case of Novel Antitubercular Drug–Palladium Complex Containing Polymeric Microparticles

“…Liu et al demonstrated a similar behavior for colloidal particle dispersions that according to size and concentration accumulate on the MP surface, but, at high concentrations, they distribute evenly thickening the outer wall of the droplet and thus opposing to shell collapse at high buckling regime …”

“…Most literature addresses spray‐drying of homogenous solutions or colloidal suspensions, which are made of homogeneous particles, and only a few works deal with irregular noncolloidal drug particles . This is the case of the second‐line antitubercular drug–Pd complexes synthesized in our laboratory that, because of the insolubility in most organic and aqueous solvents, have to be fed as suspensions.…”

Porous nano-structured micro-granules from silica-milk bi-colloidal suspension: Synthesis and characterization

“…This indeed indicates the significant role of inter-particle interaction in morphological transformation. It should be mentioned that in some of the previous works [24][25]27,[29][30][31][47][48][49][50][51][52][53][54], using single-component colloidal suspension, it was indicated that the spherical shape of droplet is retained even in the granule because of isotropic drying at slow drying rate. It has also been discussed that the formation doughnut shape is a consequence of anisotropic drying and shell buckling when drying rate is fast enough.…”