Multilamellar mesoporous silica nanoparticles using a cationic co-surfactant dual-templating method.

The utility of mesoporous silica nanoparticles (MSNs) has been repeatedly proven in a wide range of biomedical applications. The general morphology of these particles is easily modifiable by various post-grafting possibilities and adjustments within the surfactant-based template. The synthesis of multilamellar vesicular silica nanoparticles has led to the discovery of beneficial attributes regarding said particles. Depending on the synthesis process, various parameters are affected including packaging capacity, stability, drug adsorption and release. This research focused on synthesis and characterization of multilamellar MSNs using a cationic-cationic co-surfactant templating route testing various ratios of cetyltrimethylammonium bromide (CTAB) and didodecyldimethylammonium bromide (DDAB). TEM imaging showed clear differences in size and morphology between the different samples, and was further characterized by BET and BJH analysis. All multilamellar nanoparticles did exhibit a similar pore size distribution and overall gradual release of drug contents. However, the degree of drug adsorption and overtime drug release was clearly influenced by the number of layers of the MSNs, proving the utility of adjusting the template. Further experiments could be conducted to validate the utility of beta- cyclodextrin as a template regulator and to investigate both biocompatibility and biodegradability of the multilamellar MSNs.

Acid Properties of Hierarchical Zeolites Y

The article reviews different strategies towards obtaining mesoporous zeolites Y: desilication; surfactant templating and assembly of zeolite crystals. The impact of those methods on physicochemical properties is covered, with a special focus on the acidity of the samples measured with infrared (IR) spectroscopy. The methods of characterization of acidity are presented. Quaternary ammonium cations used for desilication lead to obtaining crystalline; mesoporous and highly acidic zeolites. Si-OH-Al groups of extremely high acidity can be produced by calcination in a humid atmosphere. When the conditions are optimized, post-synthetic surfactant templating allows crystalline mesoporous zeolite to be obtained with no loss of material. All mesoporous zeolites Y proved to be active catalysts in liquid phase isomerization, catalytic cracking, and other reactions.