The hydrolytic co-condensation of hydrophobic phenyltriethoxysilane (PTES) and hydrophilic γ-aminopropyltriethoxysilane (APS) was investigated in toluene and water by using hydrochloric acid (HCl) catalyst. A soluble and meltable poly(aminopropyl/phenylsilsesquioxane) (PAPSQ) was formed by controlling HCl amounts, APS/PTES molar ratios, water/silane molar ratios (Rw/si), organic co-solvents and re-equilibration steps as well. The compositions of PAPSQ bearing aminopropyl and phenyl groups with the capping of trimethylsilyl group were confirmed by element analysis, fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) and thermogravimetric analysis (TGA). Differential scanning calorimetry (DSC) was employed to characterize the melting behavior of the product. PAPSQ can be easily employed as functional molecular building blocks for the synthesis of diverse and novel inorganic-organic materials.
The iron/silica magnetic composite spheres were prepared by electrochemical method and reduced in hydrogen atmosphere at different temperatures. The morphology and structure of the composite were characterized by SEM, TEM and XRD. The iron/silica microspheres exhibit essential ferromagnetic behavior characterized by magnetometry. After being coated with silica in sodium silicate solution by acidifying technology, the surface of these magnetic composite spheres is with amino-silane coupling agent for their attachment to affinity ligands. Bovine serum albumin (BSA) was covalently immobilized onto the amino-silane modified magnetic silica supports by the glutaraldehyde method. The influence of pH, ionic strength as well as the initial protein concentration on BSA immobilization was studied. The results show that such amino-silane modified magnetic composite spheres are the effective supports for bioseparation and the maximum BSA immobilization capacity (up to 87.4 mg/g) is obtained in 0.1 mol/L phosphate buffer at pH 5.0.
Polystyrene brushes were constructed on cationically modified silica nanoparticles(SiO2-CBAFS)by electrostatic-assembly.TGA,TEM,AFM and contact angle were used to characterize the mass loss,microscopic images,topology,surface property of the products,respectively.The results show that PS-NH-SO3Na can be successfully attached to the surface of SiO2-CBAFS nanoparticles by electrostatic-assembly with high grafting density,which is much higher than that from the reports;the aggregation of silica can be prevented efficiently by being assembled a monolayer of PS-NH-SO3Na;the water contact angles of the Si/SiO2-CBAFS/PS-NH-SO3Na decrease with the increase of molecular weight and the mass concentration of PS-NH-SO3Na under different environments.
