Alumina Surface Treated Pigmentary Titanium Dioxide with Suppressed Photoactivity

The aim of the optimization of the technological process was to coat the surface of the pigment in a controlled manner and to supress photoactivity in the titanium dioxide (TiO2) pigment. As part of this research, a systematic approach to TiO2 pigment surface treatment with alumina was conducted. Surface treatment with alumina plays a significant role in the improvement of TiO2 properties (e.g. weather resistance and photostability). This research encompasses a raw material analysis and process conditions study. Sodium aluminate and aluminium sulphate were used as a source of alumina hydroxide. The effectiveness of surface treatment was determined using scanning-transmission (STEM) and transmission (TEM) electron microscopy. The photoactivity of pigmentary TiO2 was determined before and after surface treatment. A controlled surface treatment process resulted in pigmentary TiO2 particles with uniform amorphous layers, which supressed the photoactivity of the pigment

Stable TiO2 dispersions for nanocoating preparation

In this research the preparation and characterization of titanium (TiO2) coated self-cleaning cellulose materials starting from TiO2 P25 powder (Degussa. Germany) was studied. The aim of the research was to decrease high aggregation of TiO2 P25 nanoparticles, using surfactant species as dispersant and/or stabilisers (considering the balance between repulsive and attractive forces), in view of the fact that TiO2 nanoparticles, when optimally separated into smaller particle populations, present the best properties in the system they are used in (coatings). For this purpose cationic alkanediyl-alpha,omega-bis-N-dodecyl-N, N'-dimethyl-ammonium bromide (Gemini) and anionic sodium dodecyl sulphate (SDS) surfactants were applied, with concentrations under their CMSs. Size and zeta-potential (zeta-potential) characterization of stable colloidal dispersions were performed. For stable 0.5, 2.5 and 5.0 mg/mL TiO2 dispersions in the presence of 250 x 10(-6) mol/L Gemini surfactant (zeta-potential similar to 40 mV) only two scattering populations were determined, at 78-95 nm and at similar to 280 nm. As a proof of stabilized TiO2 P25-surfactant colloidal dispersions uniform coatings were obtained, generated at the fibre surfaces, which were analyzed by scanning electron microscopy (SEM). With the usage of proper amounts of surfactants, homogeneous thin TiO2 coatings were formed. Superior dense coatings on the fibre surfaces were formed after treatment in 5.0 mg/mL aqueous TiO2 P25 dispersions, in the presence of 250 x 10(-6) mol/L Gemini surfactant in 5.0 x 10(-3) Mol/LKBr at 25 degrees C. In addition to that, self-cleaning test was performed. Higher photocatalytic activity was determined for samples with denser coatings. Fibres with thin coatings had a lack of photocatalytic activity. (C) 2009 Elsevier B.V. All rights reserved

Light-induced Cleaning of CdS and ZnS Nanoparticles: Superiority to Annealing as a Postsynthetic Treatment of Functional Nanoparticles

The generation of clean CdS nanoparticles from as-synthesized ones was examined using visible light. Irradiating visible light onto the nanoparticles removes organic impurities from the synthesis of CdS, while preserving the crystalline phase and nanoscale structure of the as-synthesized semiconductor as well as creating mesopores. Compared with conventional thermal annealing, which causes oxidation and sintering of nanoparticles, the indigenous light-induced cleaning provides a better post-treatment procedure for photoactive semiconductor nanoparticles. A similar feature was also observed for the ZnS nanoparticle system. The water reduction activity (lambda >= 420 nm) of light-treated CdS was 5 times higher than that of annealed CdSclos

Synthesis, characterization and in vivo drug delivery study of a biodegradable nano-structured molecularly imprinted polymer based on cross-linker of fructose

In this study, a new biodegradable cross-linker agent based on fructose was reported for fabrication of brain targeted molecularly imprinted polymer (MIP). The applied strategy for targeting drug delivery was based on two mechanisms. Firstly, the magnetic structure of prepared MIP which facilitates the aggregation of carrier near target tissue under magnetic field. Second, the tendency of brain cell to use the produced fructose during degradation of MIP as fuel. In synthesis procedure magnetic fluorescent multi core shell structure MIP was prepared via co-precipitation polymerization in the presence of olanzapine as template and fructose with double acts, as monomer and cross-linker. Various kinds of in vitro and in vivo experiments were carried out to indicate the considered properties of carrier. The obtained data confirmed the designed carrier olanzapine satisfactorily meet the requirement in brain drug delivery application. The structure of magnetic fluorescent molecularly imprinted polymer as a carrier for targeting delivery of olanzapine to brain. [Display omitted] •Biodegradable carrier for brain drug delivery was designed.•The nano-sized structure of product simplifies it’s guidance through vessels.•The tendency of target cells to use the carrier as fuel improves the efficiency.•In-vivo and in-vitro experiments proved the efficiency of carrier

Formulation of Pickering emulsions for the development of surfactant‐free sunscreen creams

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