Nucleation Points: The Forgotten Parameter in the Synthesis of Hydrogel-Coated Gold Nanoparticles

The implementation of gold-hydrogel core-shell nanomaterials in novel light-driven technologies requires the development of well-controlled and scalable synthesis protocols with precisely tunable properties. Herein, new insights are presented concerning the importance of using the concentration of gold cores as a control parameter in the seeded precipitation polymerization process to modulate—regardless of core size—relevant fabrication parameters such as encapsulation yield, particle size and shrinkage capacity. Controlling the number of nucleation points results in the facile tuning of the encapsulation process, with yields reaching 99% of gold cores even when using different core sizes at a given particle concentration. This demonstration is extended to the encapsulation of bimodal gold core mixtures with equally precise control on the encapsulation yield, suggesting that this principle could be extended to encapsulating cores composed of other materials. These findings could have a significant impact on the development of stimuli-responsive smart materials.

Improvement of Stirred Tank for Aluminum Hydroxide Seeded Precipitation

The known designs of tank for precipitation of aluminum hydroxide from sodium aluminate solution, used in the production of alumina are considered, and the improvement of the design of the precipitator with mechanical mixing is proposed, which allows to intensify the process of precipitation and to avoid strong caustic module of the solution changes.