Octa-aminopropyl Polyhedral Oligomeric Silsesquioxane Research Articles

A novel proton exchange membrane with long-range ordered proton transport pathways through modulation of interfacial interactions via amino-functionalized polyhedral oligomeric silsesquioxane-grafted graphene oxide

Nano octa-aminopropyl polyhedral oligomeric silsesquioxane (OA-POSS) was grafted into graphene oxide (GO) via covalent bonding to synthesize OA-POSS-g-GO. A novel SP/OA-POSS-g-GO proton exchange membrane was prepared by adding sulfonated poly (ether ether ketone) (SPEEK, SP). OA-POSS was well dispersed on GO to form an ordered acid-base pair with SPEEK, which facilitated the construction of continuous ion channels. GO as a carrier facilitated the construction of long-range proton conduction pathways in the membrane. The strong interactions between OA-POSS and SPEEK along with the synergistic effect of GO modulate the size of ionic clusters and increased the bound water ratio within the membrane. The conductivity of the SP/OA-POSS-g-GO-2 membrane (80 °C, 95% RH) reached 0.2096 S⋅cm−1, which was 1.7 times higher than that of the SPEEK membrane (0.1265 S⋅cm−1). The conductivity of the SP/OA-POSS-g-GO-2 membrane increased at 100 °C and 40% RH, while that of the SPEEK membrane decreased with the temperature increased above 80 °C. The maximum power density of the single cell assembled from the composite membrane reached 305.8 mW⋅cm−2 at 80 °C and 95% RH, which was 1.4 and 1.3 times higher than that of the SPEEK and Nafion 117 membrane, respectively.

Modification of ricinoleic acid based nonisocyanate polyurethane using polyamine containing polyhedral oligomeric silsesquioxane

AbstractBiomass‐based polymers and their property regulation using functional materials have attracted much interest. In this work, ricinoleic acid‐derived cyclic carbonate was prepared and applied to the synthesis of nonisocyanate polyurethane (NIPU) with aliphatic diamine, in which octa(aminopropyl) polyhedral oligomeric silsesquioxane (OAP‐POSS) was incorporated as polyamine to partially or totally substitutes for the diamine to introduce POSS units into the polymer thus regulating the properties of the resultant material. In the curing process, Fourier transform infrared spectroscopy (FT‐IR) was used to track the reaction and curing at 50°C for 12 h was found to be sufficient for the polymerization. A series of POSS modified NIPUs were obtained by altering the molar fraction of OAP‐POSS in total amine components and the material with the highest thermal stability, shore hardness and water resistance was accessed with 100% substitution of OAP‐POSS for diamine.

Polyhedral oligomeric silsesquioxane (POSS)-modified citric-acid coated magnetic Fe3O4 nanoparticles for anticancer drug delivery

In this work, magnetic nanoparticles coated with citric acid (Fe3O4@Cit) were synthesized via co-precipitation strategy. Then, Fe3O4@Cit was modified with octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt nanoparticles (OAPOSS NPs) by amidation reaction between carboxylic acid end groups on Fe3O4@Cit and the amine groups of OAPOSS surface (Fe3O4@Cit@OAPOSS). The key point of this approach is utilizing a symmetric nanosized cagelike POSS NPs as coating material to obtain novel hybrid drug nanocarrier. The successful preparation of nanocarrier (Fe3O4@Cit@OAPOSS) was confirmed by various techniques. Drug loading and release behaviors of Fe3O4@Cit@OAPOSS were evaluated using doxorubicin (DOX), a standard anticancer model drug, in neutral and acidic conditions. Moreover, Higuchi and Korsmeyer-Peppas models were used to study the release kinetics of DOX. Obtained results confirmed the suitability of Fe3O4@Cit@OAPOSS as a potential novel nanocarrier for drug delivery.

Preparation of nano-polyhedral-oligomeric-silsesquioxane-sol based on aggregation induced emission effect and research on fluoride ion identification mechanism

Fluoride plays an indispensable role in physiological process, it is widely used in the fields of toothpaste and medicine, etc. However, excess fluoride ions can cause acute gastritis, malignant skeletal fluorosis and kidney problems. Consequently, the accurate identification of fluoride is of great importance. Therefore, we functionalized octa (aminopropyl) polyhedral oligomeric silsesquioxane (OAP-POSS) (T8) with traditional aggregation caused quenching (ACQ) aromatic luminogens to obtain phthalic-anhydride-OAP-POSS (PAOP), which not only solves the problem of ACQ, but also can be used to identify fluorine ions. The identification limit was 1.27 × 10-5 mol/L in THF(tetrahydrofuran) and 5.86 × 10-4 mol/L in DMSO (dimethyl sulfoxide). Moreover, through theoretical calculation (DFT and TD-DFT) and experiment, we further studied the action mechanism of fluorine on silicon and explored the possibility of F- encapsulated in POSS cage.

Functionalization of halloysite nanotubes via grafting of polyhedral oligomeric silsesquioxane (POSS) nanoparticles for paclitaxel drug delivery

To get high loading capacity and sustained release behavior of paclitaxel (PTX) anticancer drug, halloysite (Hal) nanotubes were functionalized with octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt nanoparticles (OAPOSS NPs) as novel drug delivery system. The novel nanocarrier, OAPOSS-g-Hal, was characterized using different methods. The in-vitro release experiments showed that PTX outflow rate from OAPOSS-g-Hal at pH 5.2 was higher than pH 7.4. The release kinetics of PTX were studied using Higuchi and Korsmeyer-Peppas models. Moreover, the cytotoxicity effect of the samples against cancer cells was studied using thiazolyl blue tetrazolium bromide assay (MTT). All the above results showed that OAPOSS-g-Hal had a great potential to be a novel drug delivery system.

Paclitaxel nano-conjugated to polyhedral oligomeric silsesquioxane (POSS) nanoparticles as a novel water-soluble prodrug

Condensed polyhedral oligomeric silsesquioxane (POSS) family of materials are very attractive as a nanoscale drug delivery system in cancer therapy. This work describes a novel method for conjugation of poorly soluble anticancer drug paclitaxel (PTX) to octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt nanoparticles (OA-POSS NPs). The synthesized nanoconjugate of PTX and OA-POSS NPs (PTXn-OA-POSS8-n prodrug) was fully soluble in aqueous solution as compared to the free PTX.

Corrosion resistance and adhesion behavior of an octa-(aminopropyl) polyhedral oligomeric silsesquioxane-modified graphene oxide-incorporated conversion coating for hot-dip galvanized steel

Graphene oxide (GO) was modified by a novel octa-(aminopropyl) polyhedral oligomeric silsesquioxane (OA-POSS) to improve its dispersion in a waterborne matrix. The modified GO was incorporated into preparing an eco-friendly conversion coating for the hot-dip galvanized layer. The compositions of the conversion coatings were unaffected by the presence of the mGO, but surface defects were modified. The corrosion current density was decreased to 6.50 × 10−5 A/cm2 and the corrosion rate was reduced to 9.69 mm/year by modified GO incorporation. Increased resistances to charge transfer and mass diffusion at one order of magnitude were also obtained. Moreover, the adhesion strength of the as-prepared conversion coating was improved 70% after the mGO addition, which effectively inhibited topcoat exfoliation.

A facile approach to incorporate silver nanoparticles into solvent-free synthesized PEG-based hydrogels for antibacterial and catalytical applications

This work aimed to immobilize silver nanoparticles with catalytic and antibacterial activity (AgNPs) inside of the PEG-based hydrogel through a facile and green design. First, the hybrid hydrogels were prepared under solvent-free conditions based on dianhydride ethylenediamine tetraacetic acid, poly (ethylene glycol) of different molar mass, glycerol, and octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt as organic and inorganic cross-linker agent. The well-dispersed AgNPs were fabricated in-situ in the polymeric matrix of the hybrid hydrogel through the reduction of Ag+ by NaBH4. The resulting hybrid nanocomposite hydrogels were characterized by various techniques, such as FT-IR spectroscopy, SEM, TEM, EDX, XRD, BET, and TGA. The swelling behavior, the antibacterial activity against the bacteria S. aureus (Gram-positive), and E. coli (Gram-negative), as well as the catalytic efficiency for the reduction reaction of 4-nitrophenol to 4-aminophenol of the nanocomposite hydrogels prepared, were examined. The facile and mass production synthetic method of the nanocomposite hydrogels, excellent dispersion of the AgNPs inside the hydrogel matrix, excellent catalytic recyclability, and antibacterial activity are some of the advantages of this system. The maximum inhibition zone was found to be 17.4 and 15.9 mm against the gram-positive species S. aureus and the gram-negative E. coli, respectively. Besides, the maximum catalytic activity was achieved in a short time period of 30 s.

Role of cellulose-based composite materials in synergistic reinforcement of environmentally friendly waterborne polyurethane

In this study, a graft modified Octa(aminopropyl) polyhedral oligomeric silsesquioxane (OPOSS)/ TEMPO-oxidized cellulose microfibrils (TOCMF) nanocomposite material (named PC) was prepared by a simple peptide-forming reaction to overcome the disadvantages of nanocellulose materials which have limited their application in environmentally friendly waterborne polyurethanes. The modified vegetable oil-based waterborne polyurethane (WPU) was prepared by reacting the excess amino group on the POSS with the -NCO group on the polyurethane matrix in the in-situ polymerization, in which the POSS particles function as a button-like bond between the oxidized cellulose and the polyurethane matrix. And the similar filamentous structure of TOCMF to the linear polyurethane matrix structure could greatly weaken the negative impact of the rigid structure of POSS particles on processability (Elongation at break). The performance test results showed that the mechanical properties, thermal stability and water resistance of the modified WPU composite film are greatly improved by the synergistic effect of the two nano materials. The initial decomposition temperature and water contact angle of the WPU composite film with a PC content of 0.7 wt.% were increased by 41.9 °C and 10°, respectively. Especially, the tensile strength of WPU/PC-0.7 wt.% was twice that of pure WPU.

Liquid-like secondary amine containing POSS as reactive nanoadditive to improve the anticorrosion performance of epoxy coating

The octaaminopropyl polyhedral oligomeric silsesquioxane (OapPOSS) was firstly synthesized through hydrolytic condensation of 3-aminopropyltriethoxysilane. Then, the secondary amine containing POSS was prepared by Michael addition reaction of OapPOSS and diethyl maleate. The resulting hybrid nanomaterial is a viscous liquid that can be uniformly dispersed in the epoxy resin as a reactive component. Results of electrochemical impedance spectroscopy indicated that functionalized POSS significantly enhanced the anticorrosion performance of epoxy coatings. The POSS, acts as a cross-linkage, improved the crosslink density of resin matrix and enhanced the impermeability of composite coatings.

Silver and copper nanoparticles stabilized on ionic liquids-functionalized polyhedral oligomeric silsesquioxane (POSS): Highly active and recyclable hybrid catalysts

Two novel heterogeneous hybrid catalysts were successfully synthesized using octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt (OA-POSS) and ionic liquids, followed by immobilization of Cu and Ag nanoparticles. The obtained hybrid catalysts, Cu@POSS-ILs and Ag@POSS-ILs, were characterized using FT-IR, SEM, EDX, TEM, XRD and TGA. Catalytic studies demonstrated that Cu@POSS-ILs was an excellent catalyst for click reaction in aqueous medium. Furthermore, Ag@POSS-ILs was also exhibited to be an active catalyst for 4-nitrophenol (4-NP) reduction. Simple preparation and easy catalysts recovery and recyclability of Cu@POSS-ILs and Ag@POSS-ILs for at least 3 and 6 runs, respectively, without loss of catalytic activity could be considered as important advantageous from catalytic application point of view.

Enhanced Performance of Near-Infrared-Absorption CdSeTe Quantum Dot-Sensitized Solar Cells Via Octa-Aminopropyl Polyhedral Oligomeric Silsesquioxane Modification

The charge recombination caused by surface defects limits photovoltaic properties of quantum dot-sensitized solar cells (QDSSCs), which can be suppressed by modifying organic or inorganic molecules and atomic ligands. In this paper, octa-aminopropyl polyhedral oligomeric silsesquioxane (OA-POSS) connected and modified near-infrared absorption CdSeTe quantum dots (QDs) through coupling agent (1-ethyl-3-3-dimethylaminopropyl carbodiimide hydrochloride). The results suggest that OA-POSS reduces the surface defects of CdSeTe QDs and suppresses charge recombination. Therefore, the power conversion efficiency improves nearly 41%, which increases from 2.00% to 2.82%.

A novel high-flux, thin-film composite desalination membrane via co-deposition of multifunctional polyhedral oligomeric silsesquioxane and polyoxometalate

This work describes the synthesis of a novel organic–inorganic nanocomposite membrane via an efficient one-pot approach of co-deposition of octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt (OA–POSS) and polyoxometalate (POSS–Mo36) onto a support membrane. The structure and morphology of the thin film nanocomposite (TFN) membranes were characterized by FT-IR spectroscopy, atomic force microscopy (AFM), energy-dispersive X-ray analysis (EDX), and scanning electron microscopy (SEM). In addition, the effect of POSS–Mo36 on the performance of the thin film nanocomposite (TFN) membranes was investigated in a forward osmosis (FO) process. Experimental results demonstrate the enhanced desalination performance of the synthesized as compared to thin-film composite (TFC) polyamide membranes.

Double network hydrogel of sodium alginate/polyacrylamide cross-linked with POSS: Swelling, dye removal and mechanical properties.

In this work, for the first time, we presented a novel design strategy to fabricate a new type of Octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt (OA-POSS)-based Alg/PAAm DN gels, consisting of PAAm gel as the first chemical network and Alg/OA-POSS gel as the second chemical-physical network. Incorporation of OA-POSS nanoparticles with various feed ratio into the second network not only led to form strong coordination interactions but also in comparison to the other Alg/PAAm gels demonstrated superior mechanical properties. pH, temperature, contact time and salt effects parameters were studied on the swelling and dye removal properties of the synthesized DN hybrid hydrogels. The adsorption experiments exhibited that 20 mg of Alg/PAAm/OA-POSS1 showed the maximum adsorption capacity for methylene blue (MB) at pH 9 and 11. Dye adsorption kinetics were modeled by the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetic equations under different conditions. Additionally, adsorption isotherms of the adsorption of MB were analyzed.

Organic-inorganic hybrid carbon dots for cell imaging

In this paper, nitrogen-doped carbon dots (CDs) had been synthesized directly by one-step ultrasonic treatment under mild conditions. During the functionalization process, Octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt (OA-POSS) was used as stabilizing and passivation agent, which lead to self-assembling of CDs in aqueous medium solution. OA-POSS was obtained via hydrolytic condensation of γ-aminopropyl triethoxy silane (APTES). The average size of CDs prepared was approximately 3.3 nm with distribution between 2.5 nm and 4.5 nm. The prepared organic-inorganic hybrid carbon dots have several characteristics such as photoluminescence emission wavelength, efficient cellular uptake, and good biocompatibility. The results indicate that OA-POSS can maintain the fluorescence properties of the carbon dots effectively, and reduced cytotoxicity provides the possibility for biomedical applications. More than 89% of the Hela cells were viable when incubated with 2 mg ml−1 or lesser organic-inorganic hybrid carbon dots. Thus, it provides a potential for multicolor imaging with HeLa cells.

Effect of carbon nanotubes and octa-aminopropyl polyhedral oligomeric silsesquioxane on the surface behaviors of carbon fibers and mechanical performance of composites

A kind of carbon fiber/carbon nanotubes/octa-aminopropyl polyhedral oligomeric silsesquioxane (CF/CNTs/POSS for short) reinforcement was prepared by grafting CNTs and OA-POSS to CFs surfaces in order to improve the mechanical properties and interfacial performance. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle testing and analysis were applied to characterize the carbon fibers surface. Tensile testing, bending testing and interlayer shear strength (ILSS) testing were employed to analyze the mechanical properties of composites. The experimental results of SEM and XPS indicate that CNTs and OA-POSS are grafted uniformly on fibers surface with chemical bonding of NH in CNTs and POSS and COOH on CFs surface. The contact angle test and analysis results show that the surface energy of modified CFs decrease compared with that of the unmodified. Furthermore, the mechanical properties of composites after coating with CNTs and OA-POSS are enhanced effectively. Especially, the properties of composites fabricated by CF/1%CNTs/POSS are significantly improved, because OA-POSS increases the interfacial strength and CNTs increases the thickness of the interfacial transition layer, which both improves the interface defects diffusion of composites. Therefore, CF/CNTs/POSS can improve the performance of the composites by forming interface transition layers.

Fabrication of POSS-coated CdTe quantum dots sensitized solar cells with enhanced photovoltaic properties

Surface trap defects limit application of quantum dots (QDs) in solar cells. The trapping states can be efficiently suppressed by modifying small molecular and atomic ligands on the core QDs. In this paper, octa-aminopropyl polyhedral oligomeric silsesquioxane (OA-POSS) was coated on CdTe QDs as capping agent to decrease surface defect density and to increase power conversion efficiency (PCE) of the CdTe QDs. POSS-CdTe QDs were prepared by conjugating OA-POSS to CdTe QDs through condensation reaction utilizing EDC. The light absorption region of CdTe QDs remains unchanged and the fluorescence intensity increases after the OA-POSS modification. The PCE of the POSS-CdTe QDs sensitized solar cells (QDSCs) is enhanced by 40% in comparison with that of CdTe QDSCs, which increase from 1.46% to 2.05% under 1.5 G one full sun illumination. The electrochemical impedance spectroscopy (EIS) measurements confirmed the suppressed charge recombination process in internal QDs and TiO2/QDs/electrolyte interfaces with the modification of OA-POSS around CdTe QDs.

Effect of octa(aminopropyl) polyhedral oligomeric silsesquioxane (OapPOSS) functionalized graphene oxide on the mechanical, thermal, and hydrophobic properties of waterborne polyurethane composites

ABSTRACTA novel graphene nanomaterial functionalized by octa(aminopropyl) polyhedral oligomeric silsesquioxane (OapPOSS) was synthesized and then confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), Raman spectroscopy, X‐ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy with energy‐dispersive X‐ray spectroscopy (SEM EDX), atomic force microscopy, and X‐ray diffraction. The obtained functionalized graphene (OapPOSS‐GO) was used to reinforce waterborne polyurethane (WPU) to obtain OapPOSS‐GO/WPU nanocomposites by in situ polymerization. The thermal, mechanical, and hydrophobic properties of nanocomposites as well as the dispersion behavior of OapPOSS‐GO in the polymer were investigated by TGA, a tensile testing machine, water contact angle tests, and field emission SEM, respectively. Compared with GO/WPU and OapPOSS/WPU composites, the strong interfacial interaction between OapPOSS‐GO and the WPU matrix facilitates a much better dispersion and load transfer from the WPU matrix to the OapPOSS‐GO. It was found that the tensile strength of the OapPOSS‐GO/WPU composite film with 0.20 wt % OapPOSS‐GO exhibited a 2.5‐fold increase in tensile strength, compared with neat WPU. Better thermal stability and hydrophobicity of nanocomposites were also achieved by the addition of OapPOSS‐GO. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44440.

In Vitro Studies of Polyhedral Oligo Silsesquioxanes: Evidence for Their Low Cytotoxicity.

As scientific literature considers polyhedral oligosilsesquioxanes (POSS) as potential drug delivery systems, it is necessary to check their impact on mammalian cells. Toxicity of octaammonium chloride salt of octaaminopropyl polyhedral oligomeric silsesquioxane (oap-POSS) towards two cell lines: mouse neuroblastoma (N2a) and embryonic mouse hippocampal cells (mHippoE-18) was studied. Experiments consisted of analysis of a cell cycle, cell viability, amount of apoptotic and necrotic cells, and generation of reactive oxygen species (ROS). POSS caused a shift in the cell population from the S and M/G2 phases to the G0/G1 phase. However, the changes affected less than 10% of the cell population and were not accompanied by increased cytotoxicity. POSS did not induce either apoptosis or necrosis and did not generate reactive oxygen species. A cytotoxicity profile of POSS makes it a promising starting material as drug carrier.

Polyhedral Oligomeric Silsesquioxane Functionalized Carbon Dots for Cell Imaging.

In the present study, octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt (OA-POSS) functionalized carbon dots (CDs/POSS) are prepared by a one-pot approach with glycerol as carbon source and solvent medium. OA-POSS serves as a passivation agent, and it is obtained via hydrolytic condensation of 3-aminopropyltriethoxysilane (APTES). During the functionalization process, the amino groups on OA-POSS combine with carboxylic groups on the bare CDs via formation of amide bond to construct organic-inorganic hybrid carbon dots. The obtained CDs/POSS are well dispersed in aqueous medium with a diameter of ca. 3.6 nm. It is demonstrated that CDs/POSS provide favorable photoluminescent property with a quantum yield of 24.0%. They also exhibit resistance to photobleaching and excellent photoluminescence stability in the presence of biological sample matrix (characterized by heavy metals and organic molecules), which facilitate cell imaging in biological systems. Both the photoluminescent emission wavelength and the fluorescence intensity depend closely on the excitation wavelength, and thus, it provides a potential for multicolor imaging as demonstrated with HeLa cells and MCF-7 cells.