And 3-aminopropyltrimethoxysilane Research Articles

Robust Organic/Inorganic Hybrid Porous Thin Films via Breath‐Figure Method and Gelation Process

AbstractA novel organic/inorganic hybrid honeycomb patterned porous thin film was prepared using the breath‐figure method combined with a sol‐gel process. An in situ formed gelable block copolymer, formed by mixing poly(styrene‐alt‐maleic anhydride)‐block‐polystyrene (P(St‐a‐MAn)‐b‐PS) and 3‐aminopropyltrimethoxysilane (APS), was used as the structure directing agent. The porous film produced was dipped into an acid aqueous solution to induce a sol‐gel process in the wall of film. As a result of gelation, the structure of this film transformed into a crosslinked silica oxide hybridized with PS, and this film resisted those organic solvents which were once good solvents for the copolymer precursor.magnified image

A facile method to prepare a series of SiO 2@Au core/shell structured nanoparticles

This paper reports a systematic investigation of the attachment of different sized gold nanoparticles (3.5–32 nm) to the polyethyleneimine (PEI) and 3-aminopropyltrimethoxysilane (APTMS)-functionalized, respectively, surfaces of different sized silica nanoparticles (60–340 nm) at room temperature. Functionalization of the surfaces of silica nanoparticles with PEI or APTMS has a profound influence on the attachment gold nanoparticles. While PEI-functionalized silica surfaces bound the midnanometer gold nanoparticles (13–32 nm), APTMS-functionalized silica surfaces did not. A series of different silica–gold core–shell composites were characterized using transmission electron microscopy (TEM) and UV–vis absorbance spectra.

Dense and square lattice-free colloid crystals of highly charged monodisperse latex particles on 3-aminopropyl trimethoxysilane-modified glass substrate

Two- and three-dimensional colloid arrays are fabricated using highly charged, monodisperse poly(styrene/sodium p-styrene sulfonate) particles and 3-aminopropyl trimethoxysilane (APTMS)-modified glass substrates at 20 °C. The colloidal array patterns were investigated by SEM, AFM, and UV–visible analyses, and the pattern on the APTMS-modified glass substrate shows a denser packing and square lattice-free pattern without any crevices, as compared with that of cleaned, bare glass substrates. The adhesion force curves obtained from AFM analysis proved a negligible attractive force between APTMS and the poly(St/NaSS) particles. The APTMS layer guaranteed the free-slipping condition to prevent scattered pinnings of drawing particles into the nuclei. Consequently, the free-slipping led to a denser hexagonal close packing and particle deformation by a stronger capillary force arising from the reduced interstices among the particles. As a result, a dense (packing density ∼ 0.80) fcc (or hcp) packing and narrower stop bands were obtained.

New approach to the immobilization of glucose oxidase on non-porous silica microspheres functionalized by (3-aminopropyl)trimethoxysilane (APTMS)

The immobilization and encapsulation of glucose oxidase (GOD) onto the mesoporous and the non-porous silica spheres prepared by co-condensation of tetraethylorthosilicate (TEOS) and (3-aminopropyl)trimethoxysilane (APTMS) in the water-in-oil (W/O) emulsion system were studied. The terminal amine group was used as the important functionality for GOD immobilization on the silica substrate. When only TEOS is used as a silica source, the disordered mesoporous silica microspheres are obtained. As the molar ratio of APTMS to TEOS ( R AT) increases, the surface area and pore volume of the silica particles measured by nitrogen adsorption and desorption method and SEM decrease rapidly. Particularly, the largest change of the surface morphology is observed between R AT = 0.20 and R AT = 0.25. The amount and the adsorption time of immobilized enzyme were measured by UV spectroscopy. About 20 wt% of GOD was immobilized into the silica substrates above R AT = 0.60 and was completely adsorbed into the substrate of R AT = 0.80 with lapse of 4 h after addition. In the measurement of the thermal stability, GOD dissolved in buffer solution loses nearly all of its activity after 30 min at 65 °C. In contrast, GOD immobilized on the surface-modified silica particles still retains about 90% of its activity after the same treatment. At this temperature, the immobilized glucose oxidase retained half of its initial activity after 4 h. It is shown that the suitable usage of functionalizing agent like APTMS as well as the control of surface morphology is very important on the immobilization of enzyme.

Synthesis and characteristics of polyimide/titania nano hybrid films

Polyimide/titania (PI/TiO 2) nano hybrid films are synthesized by sol–gel technology. [4,4′-(4,4′-Isopropylidenediphenoxy) bis (phthalic anhydride)] (IDPA), 4,4′-diaminodiphenyl ether (ODA) and 3-aminopropyltrimethoxysilane (APrTMOS) mixed entirely and reacted at room temperature to form the polyamic acid (PAA). Tetraethyl orthotitanate (Ti(OEt) 4) and actylacetone, the latter one is used as chelating agent, are then added to the polyamic acid. After imidization at high temperature, PI/TiO 2 hybrid films with different block chain length, 5000 of PAA and 15000 g mol − 1 , and a cross-linked structure are formed. The resulting hybrid films, containing relatively small amounts of titania, exhibit higher transparency and flexibility. Moreover, as compared with pure PI, the hybrid film formed from APrTMOS has better ability to form a film with a higher titania content. Due to the high and low refractive index (RI) of TiO 2 and APrTMOS, their introduction may lead to the change of the RI of hybrid films. From the transmission electron microscope (TEM) images; the particle size of titania decreases with increasing APrTMOS content. Thermal decomposition temperatures ( T d), with a 5% weight loss, are in the range of 400–540 °C. The dynamic mechanical thermal analysis showed a systematic increase of glass transition temperature, along with a broader and weaker tan δ peak with increasing titania content.

Monodisperse Organosilica Microcapsules with Functional Groups by Self-catalysis

Abstract On the basis of the self-catalytic sol–gel reaction of methyl trimethoxysilane (MTMS) and 3-aminopropyl trimethoxysilane (ATMS) at oil/water interface, monodisperse organosilica microcapsules with functional groups were prepared in one step at room temperature, without any surfactant or mediating reagent.

Different Molecular Structures at Polymer/Silane Interfaces Detected by SFG

Buried polymer/silane interfacial molecular structures were examined using sum frequency generation (SFG) vibrational spectroscopy. The silanes under investigation included n-octadecyltrichlorosilane (OTCS), n-octadecyltrimethoxysilane (OTMS), and (3-aminopropyl)trimethoxysilane (ATMS). Poly(methyl methacrylate) (PMMA) and polystyrene (PS) were among the polymers studied, and to avoid spectral confusion, deuterated polymers (d-PMMA and d-PS) were also employed. When OTCS or OTMS contacted a polymer surface, a stable and ordered interface immediately formed. It was found that the silane molecules could adopt different conformations at the interface, depending on the surface structure of the polymer. Such interfacial structures revealed evidence of interfacial molecular interactions at polymer/silane interfaces. Conversely, ATMS molecules tended to become disordered while interacting with the polymer surface, accompanied by the loss of polymer surface order. Through our SFG studies, we demonstrated that by ...

Newly developed aminopropyl-silicate immunoisolation membrane for a microcapsule-shaped bioartificial pancreas.

An aminopropyl-silicate membrane, synthesized from tetramethoxysilane (TMOS) and 3-aminopropyltrimethoxysilane (APTrMOS) by the sol-gel method, was formed onto Ca-alginate gel beads via electrostatic interactions. The permeability of the membrane could be controlled easily by changing the molar ratio of both the precursors ([APTrMOS]/[TMOS]). The aminopropyl-silicate membrane prepared at a molar ratio of 2.40 rejected gamma-globulin and BSA successfully, whereas it permeated ovalbumin. This result indicates that the molecular weight cutoff point of this newly developed aminopropyl-silicate membrane is approximately 60 kDa.

Hydroxylation of phenol over surface functionalized MCM-41 supported metal catalyst

FeCl2 and 3-aminopropyltrimethoxysilane (ATMS) were grafted on Si-MCM-41. FeCl2, FeCl3, FePc(II) and FePc(III)Cl were also grafted with ATMS coupled Si-MCM-41, whose catalytic activities were evaluated by performing hydroxylation of phenol with H2O2. These chemically modified Fe-containing samples were characterized by FT-IR. When the FeCl2/Si-MCM-41 is used, the phenol conversion reveals about 16.5%. ATMS coupled Fe-containing Si-MCM-41 catalysts improve phenol conversion by 1.5–2 times and decrease the formation of benzoquinone remarkably, while catechol/hydroquinone is in the range of 2–3.5. The redox behavior between Fe(II) and Fe(III) is discussed based on ESR spectroscopy.