And 3-aminopropyltrimethoxysilane Research Articles

Synthesis of Mesoporous Silica from Palm Oil Boiler Ash (MS-POBA) with Addition of Methyl Ester Sulfonate as a Template for Free Fatty Acid Adsorption from Crude Palm Oil (CPO)

The synthesis of mesoporous material by utilizing palm oil boiler ash (POBA) waste as the silica source and methyl ester sulfonate (MES) surfactant as the template for a high-porosity was investigated for free fatty acids (FFA) adsorption. The research was initiated with silica extraction from POBA by sodium hydroxide addition through the sol-gel precipitation method. Silica modification was carried out with MES surfactant and 3-aminopropyltrimethoxysilane (APTMS) as the co-structure-directing agent (CSDA) in different calcination temperatures. Mesoporous silica-POBA (MS-POBA) free template had a surface area, pore diameter, and pore volume (41.033 m2/g, 4.180 nm, and 0.250 cm3/g) lower than MS-POBA with the template (71.0147 m2/g, 7.923 nm, and 0.524 cm3/g). The ability of MS-POBA to adsorb FFA reached its optimum conditions with an adsorption time of 20 min and an adsorbent dosage of 0.24 g. The FFA removal by MS-POBA with the template was found to have higher adsorption ability, which was 35.54%, compared to the MS-POBA free template of 26.68%. The high porosity of MS-POBA with a template makes the FFA adsorption capacity of this material higher than MS-POBA free template.

Green delamination of 2D LDH nanosheets incorporated in mixed matrix membrane for CO2 capture

Carbon capture is a critical issue due to worsening global warming. Mixed matrix membranes incorporating 2D fillers have been attractive since they exhibit superior separation performance. In this study, the synthesis of ALDH was adjusted by sodium dodecyl sulfate (SDS) intercalation and 3-aminopropyltrimethoxysilane (APTMS) surface functionalization. Owing to this modification, the ALDH was delaminated in Pebax solutions, leading to a green process for fabricating 2D ALDH nanosheets incorporated in mixed matrix membranes. Due to the increased filler-polymer interfacial area produced by the ALDH nanosheets, CO2 passed through the membrane more quickly, which endowed the membrane with efficient CO2 separation performance. The optimal performance was obtained by adding 50 % PEGDME and 4 % ALDH to Pebax-1657, and the CO2 permeability and CO2/N2 selectivity were 460 barrer and 63, respectively. No toxic solvent was used in the process, providing an environmentally friendly method for fabricating 2D ALDH MMMs for efficient CO2 capture.

Green-AgNPs modified membrane for monitoring mercury ions in cosmetic sample using pre-concentration assisted voltammetry technique

The carcinogenic and teratogenic properties of mercury have driven the necessity for the development of highly sensitive methods capable of detecting even trace amounts of the element. In response to this need, an analysis technique has been established for mercury ions, employing preconcentration methods utilizing filter paper modified by silver nanoparticles (AgNPs) and 3-Amino propyl trimethoxy silane (APTMS). This method allows for the detection of mercury ions through the voltammetry technique, ensuring accurate and reliable results. Upon conducting analyses using this method, it was found that the tested cosmetic samples were free from Hg2+ ions, indicating the absence of mercury contamination in the cosmetics under investigation. The correlation coefficient derived from the graph of the analysis results stands at an impressive value of 0.9976, affirming the strong relationship between the measured concentrations and the actual mercury content. Additionally, the method demonstrates excellent sensitivity, as evidenced by the low limit of detection (LOD) value of 0.0483 mM and the limit of quantification (LOQ) value of 0.1611 mM.

Microhardness measurement optimization in green derived silica/polyester composites using response surface methodology

Polymer composites based on unsaturated polyester resin (UPR) and reinforced with particles based on unmodified/modified plant provenance biosilica particles were synthesized and characterized. An unsaturated polyester resin was obtained from waste poly (ethylene terephthalate (PET). Biosilaca particles are made from rice husk biomass. The surface of the produced silica particles was modified using three different silanes: 3-trimethoxysilylpropyl methacrylate (MEMO), trimethoxyvinylsilane (TMEVS), and 3-aminopropyltrimethoxysilane (APTMS). The microhardness test method was used to investigate the mechanical properties of synthesized composite material with variations in dwell times and applied loads. Optimization of composite microhardness value prediction in function of synthesized parameters (type of modification of silica particles) and measurement parameters (applied loads and dwell times) was done using the method of response surface methodology (RSM) regression analysis. The maximal microhardness values (0.459 GPa) were obtained of type modification of silica particles with vinyl with 80% confidence for 120 experimental variables. This method can be used to choose the optimal dwell time and load for comparison of measurements between different composite materials and to enable the choice of the material in terms of optimization of the quality of reinforcement and quality of interphase determined by surface modification.

Development of a biomimetic DNA delivery system by encapsulating polyethyleneimine functionalized silicon quantum dots with cell membranes.

Quantum dots (QDs) are renowned for their remarkable optoelectronic properties, making them suitable for applications such as bioimaging and optoelectronics. However, their use in gene delivery has been restricted due to the low DNA loading capacity. This study aimed to develop a biomimetic DNA delivery system by encapsulating polyethyleneimine (PEI) functionalized silicon QDs (SiQDs) with cell membranes and evaluate its potential as a gene vector in vitro. To achieve this, hydrophilic dispersed silicon QDs (PQDs) were prepared through a one-pot hydrothermal reaction of PEI and 3-Aminopropyltrimethoxysilane (APTMS). Subsequently, red blood cell membrane (RBCM) encapsulated biomimetic QDs (CM-PQDs) was obtained through the extrusion method. The CM-PQDs exhibited higher DNA loading capacity and better stability than naked SiQDs. The CM-PQDs/DNA complex was effectively taken up by cells, as observed through the fluorescence characteristics of QDs themselves. Both CM-P10QDs (prepared with PEI10k) and CM-P25QDs (prepared with PEI25k) could deliver DNA into cells and express the reporter protein successfully. CM-P25QDs showed a higher transfection efficiency of 77.32% in 293T cells and 47.11% in HeLa cells than SiQDs and CM-P10QDs. The results also indicated that cell membrane encapsulation could effectively reduce the cytotoxicity of SiQDs further. Therefore, the study concludes that CM-PQDs have the potential to serve as a safe and traceable biomimetic gene delivery system.

Carbon nanotube‐based polymer nanocomposites: Evaluation of barrier, hydrophobic, and mechanical properties for aerospace applications

AbstractThe anticorrosive and mechanical properties of carbon nanotubes (CNTs) in epoxy resin (EP) coatings have been improved by the integration of molybdenum disulfide (MoS2) and 3‐aminopropyltrimethoxysilane (APTMS) for surface modification based on CNTs. SEM/EDX, TEM, TGA/XRD, XPS, and XRD techniques were used to characterize the composites for the various formulations, including APTMS/CNTs, CNTs/MoS2, and APTMS/CNTs‐MoS2. By including APTMS/CNTs‐MoS2 composite, the EP coating exhibits improved anticorrosive and mechanical performance, as demonstrated by electrochemical methods and mechanical testing. Superior hydrophobic property of EP‐APTMS/CNTs‐MoS2 is confirmed by its WCA of 167°. Additionally, it was discovered that the EP‐APTMS/CNTs‐MoS2 had a resistance that was significantly larger (17,421 kΩ.cm2) than the plain epoxy (102 kΩ.cm2), and its hardness (1695 MPa), adhesion (19.7 MPa), and tensile (237 MPa) properties all are improved significantly. Therefore, the newly developed EP‐APTMS/CNTs‐MoS2 could act as the vital material for coating AA7475 aluminum alloy used in aerospace applications.

Effect of Addition of Oleic Acid as a Template with Tetraethylorthosilicate (TEOS) as Source of Silica on Porosity Mesoporous Silica Material

Mesoporous silica material has been synthesized using tetraethylorthosilicate (TEOS) as a source of silica, oleic acid as a template, and 3-aminopropyltrimethoxysilane (APMS) as co-structure directing agents (CSDA). The synthesis of silica material was made with a variation in the mole ratio of TEOS: Oleic acid with a ratio of 1: 0.2; 1: 0.3; 1: 0.5; 1: 0.6; 1: 0.7; 1: 0.9, and 1: 1. A mixture between TEOS and APMS was added to a mixture of oleic acid, HCl 0.1N and demineralized water then stirred at room temperature for 2 hours. Then aging, the mix at 80oC for 48 hours until solids are formed. Product separation was used in the centrifugation method. The resulting solid was dried at 50oC, and to remove the template, calcined at 550oC for 6 hours. The product of XRD analysis has a wider diffraction peak that indicates an amorphous material. The FT-IR spectrum shows the Si-OH and Si-O-Si groups which area characteristic of silica material. The product of SEM analysis offers the presence of sheets and plates of particle forms with different sizes. Adsorption desorption isotherm (BET) shows an isotherm type IV curve, and dominant pore sizes are 1.945 and 4.588 nm.

Preparation and evaluation of organosilica nanocapsules encapsulating DCOIT by using the response surface optimization

AbstractAntifouling agent 4, 5‐dichloro‐2‐n‐octyl‐4‐isothiazolin‐3‐one (DCOIT) in a one‐stage process based on the self‐catalytic reaction between methyl trimethoxysilane (MTMS) and 3‐aminopropyl trimethoxysilane (APS) in an aqueous system without any surfactants and catalysts have been developed. The optimal preparation process parameters of organosilica nanocapsules encapsulating DCOIT (DCOIT@SiNC) were determined using response surface methodology (RSM) based on the single‐factor experimental results. The results of RSM optimization showed that 49.51% encapsulation efficiency (EE [%]) would be achieved with a shell–core mass ratio of 5.59:1, a MTMS‐APS mole ratio of 1.52:1, and a reaction temperature of 31°C. DCOIT@SiNC prepared according to the RSM optimal process exhibited a decent uniform sphericity with an average particle diameter of 660.50 nm. The encapsulation was characterized by Fourier‐transform infrared and X‐ray diffraction. The loading efficiency and thermal stability were verified via thermogravimetric analysis. Compared to DCOIT, DCOIT@SiNC had better controlled release performance, and the release kinetics investigated by Riger‐peppas model indicated that the release of DCOIT was diffusion‐controlled.

A label-free optical immunoassay based on birefringence of liquid crystal for insulin-like growth factor-I sensing

Human insulin-like growth factor-I (IGF-I) is a pleiotropic polypeptide hormone, which has been widely utilized for the diagnosis and management of growth hormone (GH) related disorders and diseases. In this work, we verify a label-free optical biosensor based on nematic liquid crystals (LCs) of 4-cyano-4-pentylbiphenyl (5CB) for ultrasensitive sensing of trace IGF-I in human serum samples. 5CB shows unique birefringence driven by the reorientation of the self-assembled N, N-dimethyl-N-(3-(trimethoxysilyl)propyl)−1-octadecanaminiuchloride (DMOAP) on glass. IGF-I antibody (AbIGF-I), as a specific recognition element, can be immobilized onto modified glass surface through a cross-linker of glutaradehyde (GA) and (3-aminopropyl) trimethoxysilane (APTES). Based on the number of specific recognition and binding between antibody (AbIGF-1) and antigen (AgIGF-1), the LC film exhibits gradual change from dark to bright under crossed polarizer. Under optimized conditions, the constructed LC-based biosensor demonstrates high sensitivity to IGF-I with a detection limit (LOD) of 1.0 ng/mL and a linear range of 10.0–2000.0 ng/mL (R2 = 0.989). This detection method possesses the advantages of easy construction, rapid sensing, good stability and repeatability, and high specificity for distinguishing IGF-I from other interfering proteins. Meanwhile, the format of biosensor could quickly detect IGF-I within a physiological range, providing profound information for prevention and treatment of GH-IGF-I axis related diseases in clinical diagnosis.

Investigation of aminolysis routes on PET fabrics using different amine‐based materials

AbstractIn this study, functionalization of PET fabrics with amino groups was achieved by aminolysis. Aminolysis routes were explored using different amine‐based materials including ethylenediamine (EDA), triaminotriethylamine (TAEA) and (3‐aminopropyl)trimethoxysilane (APTMS), (3‐trimethoxy‐silylpropyl)diethylentriamine (TRIAMO) in addition to amino‐functionalized silica nanoparticles as amino‐silane based reagents. The samples were deeply characterized by SEM, AFM, and XPS. Abrasion and tensile tests were carried out to evaluate the mechanical properties of the modified fabrics. Results showed that aminolysis conducted with EDA and TAEA as amino based reagents lower the performances of PET, while dense coatings can be deposited on the fibres by amino silane‐based reagents that act as protective layers. APTMS modified PET presented improved abrasion resistance compared to the native PET. The antibacterial activity of the PET surfaces functionalized with the different amino groups was also evaluated using the gram‐negative bacterium A. fischeri antibacterial assay. The results showed improved antibacterial performances of the native textile treated with APTMS and TAEA based reagents.

Influence of 1D and 2D carbon nanostructures in silica-based aerogels

Carbon nanostructures-silica aerogel composites were synthesized and characterized to assess the effect of carbon nanotubes (CNTs) or graphene oxide (GO) on the silica aerogel properties. The sol-gel chemistry was based on methyltrimethoxysilane (MTMS) and 3-aminopropyltrimethoxysilane (APTMS) as silica precursor system, with varying amounts of APTMS (0–20% mol of Si). APTMS significantly impacted the materials' physical properties. The chemistry and microstructure were investigated by FTIR, NMR, TEM, SEM, SAXS and BET. The addition of CNTs induced the growth of the silica matrix around them; thus, an elongated shape was observed in the silica structural units. APTMS and CNTs have a synergistic effect on the mechanical properties, increasing the Young's modulus up to 14 MPa. Small amounts of carbon materials (∼1 wt%) in the MTMS-matrix improved its thermal insulation property, particularly for temperatures above 50 °C. In terms of electrochemical properties, the carbon nanostructures lead to higher specific capacitances and a reduction in resistance. The characterizations here performed allowed a better understanding of the interactions between the silica and carbon phases. The possibility to obtain materials with tailored properties demonstrates their application potential in several areas, such as thermal insulation and energy storage.

COMPARISON OF THE INFLUENCE OF PHYTIC ACID AND SILANE ADDITIVES ON CORROSION RESISTANCE OF CERAMIC COATINGS ON Mg ALLOY BY PEO METHOD

Phytic acid (PA) and 3-aminopropyltrimethoxysilane (APTMS) were selected as organic additives and respectively doped into Na2SiO3-NaOH electrolyte to prepare ceramic coatings on AZ31B Mg alloys by Plasma Electrolytic Oxidation (PEO) method. The influences of two additives on corrosion resistance of the PEO coatings were compared. The microstructure, composition and corrosion resistance of the PEO coatings were examined by SEM, EDX, XPS, XRD, potentiodynamic polarization test and EIS measurement. The results indicated that each additive increased both the coating thickness and corrosion resistance. However, the PA-doped PEO coating achieves larger thickness but exhibits worse corrosion resistance than the APTMS-doped PEO coating due to larger pore size and looser microstructure.

Detailed investigation of structural and magnetic properties of multiphase binary Pd-Co alloys prepared by modified polyol process

Pd-Co based magnetic alloy nanoparticles were prepared by the modified polyol process and stabilized by polyvinylpyrrolidone (PVP) and 3-aminopropyl-trimethoxysilane (APES) capping agents and further reduction of metal salts with Sodium borohydride (NaBH4) at high temperature to form desired NPs. We have a detailed investigation of the effect of Pd concentration in the Pd-Co alloy NPs on structural and magnetic properties. XRD and Rietveld refinement analyses were confirmed that the multiphase structures of fcc-PdCo, fcc-Co, and hcp-Co phases coexist at low Pd loading samples. Over %50 of Pd loading resulted in a single fcc-PdCo phase with reduced lattice parameter to 4.0079 Å and d(111)-space to 2.31 Å. TEM and SEM images reveal well dispersed and uniformly distributed NPs with an average particle sizes of below 7 nm. The elemental compositions and the characteristic OH, CH, CO stretching peaks of capping agents were confirmed by EDS and FT-IR spectrums, respectively. M(T) and M(H) curves revealed that there are multi magnetic phase transitions in the Pd-Co structure as a function of Pd loading from superparamagnetic to ferromagnetic phase or back to superparamagnetic phase by reducing the temperature from 300 K to 5 K. We observed that the blocking temperature (TB) could not be detected due to 5% Pd loading below 300 K, while it reduced up to 55 K at high Pd loading of 62%. The coercive field (Hc) was increased to ~1900 Oe for Pd0.62Co0.38 sample due to the smallest particle size as 5.26 nm. The highest amount of Co resulted in maximum saturation magnetization (Ms) up to 65.5 emu/g for 5% Pd concentration. We measured the Mr/Ms ratios were less than 0.5, which is due to the internal stress that results in the uniaxial magnetic anisotropy in the structure. The maximum Keff and μf.u. values were found to be over 12.9 × 106 erg/cm3 and 0.72 μB at 5 K for 5% Pd concentration, respectively.

A study on the anticorrosion performance of epoxy nanocomposite coatings containing epoxy-silane treated nanoclay on mild steel in chloride environment

The halloysite nanoclay was chemically modified with different silanes such as 3-glycidoxypropyl trimethoxysilane (GPTMS) and 3-aminopropyl trimethoxysilane (APTMS) and examined by FTIR, TGA, and XRD techniques. The incorporation of functionalized nanoclay in the epoxy resin enhances the protectant properties of the coated steel. The anticorrosion properties were investigated by electrochemical measurements in chloride environment. The mild steel coated by epoxy-APTMS/clay nanocomposite displayed higher coating resistance (Rc = 5407.88 kΩ cm2) in comparision with pure epoxy coating (Rc = 549.51 kΩ cm2).The mechanical properties (hardness, adhesion strength and tensile strength) of the resultant nanocomposite were also evaluated. The introduction APTMS/clay (4 wt%) to the epoxy coating helps to increase the tensile strength to 80 MPa which is 25% higher than pure epoxy coating. The surface topographies of the studied coatings were investigated by SEM/EDX analysis. The results from electrochemical and mechanical investigations indicated that the as synthesized coatings consisting of epoxy-silanes/clay possessed an excellent adhesion, microhardness and corrosion protection properties.

Corrosion protection performance and interfacial interactions of polythiophene/silanes/MnO2 nanocomposite coatings on magnesium alloy in marine environment

The silane functionalized MnO2 nanoparticles were incorporated in polythiophene (PT) to produce PT/silanes/MnO2 nanocomposites. The surfaces of MnO2 nanoparticles were modified with ethyltrimethoxysilane (ETMS), 3-glycidyloxypropyltrimethoxysilane (GPTMS), and 3-aminopropyltrimethoxysilane (APTMS) and characterized by X-ray diffraction (XRD) studies. The corrosion resistance of newly synthesized PT, PT-ETMS/MnO2, PT-GPTMS/MnO2, and PT-APTMS/MnO2 composite coatings of magnesium alloy (AZ91A) was evaluated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP) studies, and scanning electrochemical microscopy (SECM) immersed in natural seawater for several days. The PT-APTMS/MnO2 nanocomposite coatings showed an excellent resistance against corrosion with a charge transfer resistance of over 7517.85 kΩ cm2, which were higher than that of the PT coating (548.25 kΩ cm2) after 80 days immersion in seawater. The coating with MnO2 nanoparticles modified by APTMS, GPTMS, and ETMS groups showed no significant penetration by corrosive ions during 80 days’ immersion due to the strong chemical bonding between amino/epoxide/ethyl groups on MnO2 and the sulfur of PT. Decreased current was detected at the scratch of investigated nanocomposite coatings by SECM analysis. The affinity between PT and silanes/MnO2 nanoparticles is enhanced due to their interfacial interactions, which improves the dispersion of silane functionalized MnO2 nanoparticles in PT to produce uniform coatings. Scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX) and XRD technique of synthesized nanocomposite coatings confirmed the presence of corrosion products which block the dissolution of Mg alloy. Excellent mechanical properties are shown by the investigated coatings. Highlights Newly synthesized polythiophene (PT), PT-ETMS/MnO2, PT-GPTMS/MnO2, and PT-APTMS/MnO2 composite coatings on magnesium alloy (AZ91A) was evaluated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP) studies, and scanning electrochemical microscopy (SECM) immersed in natural seawater for several days. The addition of MnO2 in the polymer resulted in the reduction of porosity of the coatings significantly. The silane functionalized MnO2 nanoparticles loaded nanocomposite coatings demonstrated excellent resistance against corrosion than that of the MnO2-free PT coating after 80 days of immersion. The corrosion resistance of the coatings was considerably improved due to enhanced interfacial interactions between silane functionalized MnO2 nanoparticles and PT by chemical bonding. The coating with MnO2 nanoparticles modified by amino (APTMS), epoxide (GPTMS), and ethyl (ETMS) groups showed no significant penetration by corrosive ions during 80 days’ immersion due to the strong chemical bonding between amino/epoxide/ethyl groups on MnO2 and a sulfur heterocycles of PT without changing the original crosslinking structure of PT. Interfacial interaction between phases also plays a key role in the affinity between MnO2 and PT, which determines the dispersion of MnO2 in coatings and uniform morphology of composite coatings.

Thermal and mechanical properties of epoxy resin reinforced with modified iron oxide nanoparticles

AbstractEpoxy polymers, having good mechanical properties and thermal stability, are often used for engineering applications. Their properties can be further enhanced by the addition of iron oxide (Fe3O4) nanoparticles (NPs) as fillers to the resin. In this study, pristine Fe3O4 NPs were functionalized with polydopamine (PDA), (3‐glycidoxypropyl)trimethoxysilane (GPTMS), and (3‐aminopropyl)trimethoxysilane (APTES). X‐ray diffraction and scanning electron microscopy (SEM) were used to study any changes in the crystal structure and size of the NPs while Fourier‐Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) were used to ensure the presence of functional groups on the surface. The mechanical properties of the Fe3O4‐based nanocomposites generally improved except when reinforced with Fe3O4/PDA. The maximum improvement in tensile strength (∼34%) and fracture toughness (∼13%) were observed for pristine Fe3O4‐based nanocomposites. Dynamic mechanical analysis (DMA) showed that the use of any of the treated NPs improved the material's initial storage modulus and had a substantial impact on its dissipation potential. Also, it was observed that the glass transition temperature measurements by DMA and differential scanning calorimetry were below that of pure epoxy. SEM of the cracked surfaces shows that the incorporation of any NPs leads to an enhancement in its thermal and mechanical properties.

Effect of silane/amine-based dopants on polymer-metal interaction of sub-surface silver nanoparticulate films

The optical and morphological properties of the vacuum-evaporated silver (Ag) nanoparticulate films on softened polyvinyl alcohol (PVA) modified with the 3-mercaptopropyl trimethoxysilane (MPTMS) and 3-aminopropyl trimethoxysilane (APTMS) dopants are reported. The topography of the particulate films is characterized by the field-emission scanning electron microscopy. The optical spectra broadening, red-shift, and the increase in the intensity values of the plasmonic resonance peak with the nature of dopant have a strong dependence on the particle size, shape, and inter-particle separation. The conducted experimental optical studies are supported by Finite Difference Time-Domain (FDTD) simulation results. Quantitative analysis of the Fourier-Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy studies confirm the surface modification of Ag nanoparticulate films on doped PVA substrates. The amount of polymer-metal interaction caused by the strongly interacting silane groups of the dopants and their influence on the morphology and optical properties are discussed.

Preparation of Green-Emissive Zinc Oxide Composites Using Natural Betacyanin Pigment Isolated from Red Dragon Fruit

In this work, we reported the synthesis of green-emissive composite materials of zinc oxide (ZnO) and isolated betacyanin pigment from red dragon fruit (RDF) extract utilizing organic linkers, i.e. (3-chloropropyl)trimethoxysilane (CPTMS) and (3-aminopropyl)trimethoxysilane (APTMS). Betacyanin was extracted using a maceration technique, while CPTMS-ZnO and APTMS-ZnO were prepared by mixing ZnO and the respective organic linker in ethanol. The obtained ZnO/CPTMS and APTMS-ZnO composites were separately added into the RDF extract, followed by stirring at room temperature for 24 h. As high as 80 and 90% of betacyanin was successfully impregnated onto CPTMS-ZnO and APTMS-ZnO, respectively. A comparison study was made by preparing RDF-CPTMS and RDF-APTMS first and then introducing them onto ZnO. In this case, as high as 81 and 100% of betacyanin in RDF-CPTMS and RDF-APTMS, respectively, were impregnated onto ZnO. These results revealed that APTMS was a better organic linker than CPTMS and the order of the steps to introduce APTMS was important. The presence of betacyanin on the composite materials was confirmed by FTIR and fluorescence spectroscopy. All the composite materials had an excitation signal at 426–428 nm and emission signals at 459 and 517–518 nm, demonstrating their promising application as green-emissive materials.

Facile Synthesis, Enhanced Photostability, and Long-term Cellular Imaging of Bright Red Luminescent Organosilica Nanoparticles.

We herein demonstrate a facile approach for the preparation of red luminescent organosilica nanoparticles (OSi NPs) via the addition reaction of indocyanine green (ICG) and (3-aminopropyl)trimethoxysilane (APTMS). Photoluminescent quantum yield (PLQY) of the resulting OSi NPs was tunable by simply changing the molar ratio of ICG and APTMS used in the reactions. Under the optimized molar ratio of ICG and APTMS, that is, 1:4, PLQY of the red luminescent OSi NPs was as high as 32%. The resulting OSi NPs presented greatly enhanced photostability, attributing to the promoted decay rate of the excited state and thus suppressed the generation of the reactive oxygen species in the OSi NPs. The integrated superiorities of high PLQY, enhanced photostability, low toxicity, and excellent biocompatibility endow the red luminescent OSi NPs extremely promising for long-term cellular imaging.

Effect of Surface Chemistry on the Glass-Transition Dynamics of Poly(phenyl methyl siloxane) Confined in Alumina Nanopores.

Broadband dielectric spectroscopy (BDS) and differential scanning calorimetry (DSC) are combined to study the effect of changes in the surface chemistry on the segmental dynamics of glass-forming polymer, poly(methylphenylsiloxane) (PMPS), confined in anodized aluminum oxide (AAO) nanopores. Measurements were carried for native and silanized nanopores of the same pore sizes. Nanopore surfaces are modified with the use of two silanizing agents, chlorotrimethylsilane (ClTMS) and (3-aminopropyl)trimethoxysilane (APTMOS), of much different properties. The results of the dielectric studies have demonstrated that for the studied polymer located in 55 nm pores, changes in the surface chemistry and thermal treatment allows the confinement effect seen in temperature evolution of the segmental relaxation time, τα(T) to be removed. The bulk-like evolution of the segmental relaxation time can also be restored upon long-time annealing. Interestingly, the time scale of such equilibration process was found to be independent of the surface conditions. The calorimetric measurements reveal the presence of two glass-transition events in DSC thermograms of all considered systems, implying that the changes in the interfacial interactions introduced by silanization are not strong enough to inhibit the formation of the interfacial layer. Although DSC traces confirmed the two-glass-transition scenario, there is no clear evidence that vitrification of the interfacial layer affects τα(T) for nanopore-confined polymer.