Polyhedral Oligomeric Silsesquioxane Nanoparticles Research Articles

Correction to: Poly(lactic acid)/poly(butylene adipate-co-terephthalate) films reinforced with polyhedral oligomeric silsesquioxane nanoparticles: a morphological, mechanical, and thermal study

Correction to: Poly(lactic acid)/poly(butylene adipate-co-terephthalate) films reinforced with polyhedral oligomeric silsesquioxane nanoparticles: a morphological, mechanical, and thermal study

Poly(lactic acid)/poly(butylene adipate-co-terephthalate) films reinforced with polyhedral oligomeric silsesquioxane nanoparticles: a morphological, mechanical, and thermal study

Poly(lactic acid)/poly(butylene adipate-co-terephthalate) films reinforced with polyhedral oligomeric silsesquioxane nanoparticles: a morphological, mechanical, and thermal study

Biosensor for ATP detection via aptamer-modified PDA@POSS nanoparticles synthesized in a microfluidic reactor

This study introduces aptamer-functionalized polyhedral oligomeric silsesquioxane (POSS) nanoparticles for adenosine triphosphate (ATP) detection where the POSS nanoparticles were synthesized in a one-step, continuous flow microfluidic reactor utilizing thermal polymerization. A microemulsion containing POSS monomers was generated in the microfluidic reactor which was designed to prevent clogging by using a continuous oil flow around the emulsion during thermal polymerization. Surfaces of POSS nanoparticles were biomimetically modified by polydopamine. The aptamer sequence for ATP was successfully attached to POSS nanoparticles. The aptamer-modified POSS nanoparticles were tested for affinity-based biosensor applications using ATP as a model molecule. The nanoparticles were able to capture ATP molecules successfully with an affinity constant of 46.5 μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu $$\\end{document}M. Based on this result, it was shown, for the first time, that microfluidic synthesis of POSS nanoparticles can be utilized in designing aptamer-functionalized nanosystems for biosensor applications. The integration of POSS in biosensing technologies not only exemplifies the versatility and efficacy of these nanoparticles but also marks a significant contribution to the field of biorecognition and sample preparation.

MoEpPOSS nanotaneciğinin PA6/TPE karışımlarının morfolojik ve reolojik özelliklerine etkisinin incelenmesi

Polyamide 6 (PA6) is one of the used engineering thermoplastics with the advantages of high resistance to chemicals and abrasion, high fatigue resistance and toughness. However, it has some disadvantages such as low impact strength and notch sensitivity. The blend of PA6 with elastomers can mitigate these shortcomings. Lately, thermoplastic elastomers (TPE) have been frequently used to toughen notch-sensitive polymers such as PA6 due to their outstanding properties such as high elasticity, recyclability, and easy processing. As it is known, obtaining superior properties in polymer blends relies on the interfacial interaction between the components of the blend. Additionally, by using compatibilizers, blends with the required properties can be created by enhancing interaction between phases, or interfacial adhesion. Recently, polyhedral oligomeric silsesquioxane (POSS) nanoparticles, organic/inorganic hybrid nanoparticles, are preferred as an alternative compatibilizer to conventional types. In this study, PA6/TPE blends were compatibilized with POSS nanoparticle with single epoxy group (MoEpPOSS). The morphological and rheological properties of PA6/TPE blends compatibilized with MoEpPOSS nanoparticle were investigated. Also, possible chemical interactions between PA6 and/or TPE and MoEpPOSS nanoparticle were determined via Fourier transform infrared spectroscopy (FTIR) analyses.

Engineered nanocomposites through embedding of smaller “organic inorganic” nanoparticles in thermoplastic Poly(2-Vinylpyridine) polymer matrix

Polymer nanocomposites (PNCs) are significant for modern and future applications owing to their multifunctionality promoted by morphology and tailored interfaces between the constituents. However, ‘forward’ engineered polymer (host) composites with smaller size nanoparticles (guest) providing desired properties remains challenging as they depend upon nanoparticles aggregation, size, shape, and loading (volume or weight) fraction. This study strategically designs and develops PNCs comprising thermoplastic poly (2-vinylpyridine) (P2VP) polymer matrix impregnated with spherical polyhedral oligomeric silsesquioxane (N-POSS) nanoparticles (diameter ∼2–5 nm) and anisotropic planar nitrogenated graphene nanoribbons (GNR, strip width ∼5–10 nm) commensurate with polymer chain radius of gyration, Rg, (or segment length ∼1.5 nm) and comparable energy scales of electrostatic interaction and attractive hydrogen bonding. We investigated static and dynamic structure and thermophysical properties to correlate with interfacial regions and the results are compared with larger graphene oxide (GO, lateral dimension ∼100–200 nm) nanosheets and silica (SiO2, ∼25–50 nm) particles. While electron microscopy revealed nanoparticle distribution, the lattice bonding, conjugation length, and mechanical properties are determined from micro-Raman spectroscopy and atomic force microscopy, respectively. The differential scanning calorimetry provided a measure of glass transition temperature, Tg, with positive shift of ∼10–18 °C with nanoparticles loading indicating strength of structural relaxation/chain rigidity behavior and thermogravimetric analysis displayed increased thermal stability and conductivity (decreased interfacial resistance). We also measured temperature dependent dc electrical conductivity and dielectric relaxation spectroscopy gaining insights into percolation and dynamic interfacial layer. This study signified understanding of interactions and interfacial regions, key element to demystify the microscopic structure-property relationships.

Processing and Characterization of UV Irradiated HDPE/POSS Fibers.

High-performance polyethylene fibers, renowned for their superior attributes encompassing a high strength, modulus, and lightness, are conventionally manufactured through the gel spinning method. However, this method is encumbered by several drawbacks, including the requisite application of a separate process to eliminate solvents from the fibers and the utilization of chemicals deleterious to both the environment and human health. Alternatively, the adoption of the melt spinning method presents a cleaner and environmentally friendly approach to attain high-performance fibers. In the present investigation, high-density polyethylene (HDPE) fibers were produced employing the melt spinning method. After the spinning process, strategic orientation procedures were implemented to enhance the crystallinity of the spun fibers. As a concluding step, seeking to elevate the overall performance of the oriented spun HDPE fibers, a cross-linking treatment was applied via UV irradiation. Notably, this study pioneers the incorporation of polyhedral oligomeric silsesquioxane (POSS) hybrid nanoparticles into HDPE during melt spinning, presenting a novel advancement aimed at further enhancing the mechanical properties of oriented HDPE fibers during UV irradiation. For this purpose, two distinct types of POSS, namely octavinyl POSS (OVPOSS) and methacryl POSS (MACPOSS), both having unsaturated double bonds capable of participating in the network structure of oriented HDPE spun during UV cross-linking, were used. The thermal, morphological, and mechanical properties, as well as the crystal structure of samples with and without POSS molecules, were investigated. The mechanical properties of the fibers exhibited higher values in the presence of OVPOSS. The incorporation of OVPOSS and MACPOSS resulted in a noteworthy improvement in the material's tensile strength, exhibiting a marked increase of 12.5 and 70.8%, respectively. This improvement can be attributed to the more homogeneous dispersion of OVPOSS in HDPE, actively participating in the three-dimensional network structure. After orientation and UV irradiation, the tensile strength of HDPE fibers incorporating OVPOSS increased to 293 MPa, accompanied by a concurrent increase in the modulus to 2.8 GPa. The addition of POSS nanoparticles thus yielded a substantial improvement in the overall performance of HDPE fibers.

Effect of Amino-Functionalized Polyhedral Oligomeric Silsesquioxanes on Structure-Property Relationships of Thermostable Hybrid Cyanate Ester Resin Based Nanocomposites.

Nanocomposites of cyanate ester resin (CER) filled with three different reactive amino-functionalized polyhedral oligomeric silsesquioxane (POSS) were synthesized and characterized. The addition of a small quantity (0.1 wt.%) of amino-POSS chemically grafted to the CER network led to the increasing thermal stability of the CER matrix by 12-15 °C, depending on the type of amino-POSS. A significant increase of the glass transition temperature, Tg (DSC data), and the temperature of α relaxation, Tα (DMTA data), by 45-55 °C of the CER matrix with loading of nanofillers was evidenced. CER/POSS films exhibited a higher storage modulus than that of neat CER in the temperature range investigated. It was evidenced that CER/aminopropylisobutyl (APIB)-POSS, CER/N-phenylaminopropyl (NPAP)-POSS, and CER/aminoethyl aminopropylisobutyl (AEAPIB)-POSS nanocomposites induced a more homogenous α relaxation phenomenon with higher Tα values and an enhanced nanocomposite elastic behavior. The value of the storage modulus, E', at 25 °C increased from 2.72 GPa for the pure CER matrix to 2.99-3.24 GPa for the nanocomposites with amino-functionalized POSS nanoparticles. Furthermore, CER/amino-POSS nanocomposites possessed a higher specific surface area, gas permeability (CO2, He), and diffusion coefficients (CO2) values than those for neat CER, due to an increasing free volume of the nanocomposites studied that is very important for their gas transport properties. Permeability grew by about 2 (He) and 3.5-4 times (CO2), respectively, and the diffusion coefficient of CO2 increased approximately twice for CER/amino-POSS nanocomposites in comparison with the neat CER network. The efficiency of amino-functionalized POSS in improving the thermal and transport properties of the CER/amino-POSS nanocomposites increased in a raw of reactive POSS containing one primary (APIB-POSS) < eight secondary (NPAP-POSS) < one secondary and one primary (AEAPIB-POSS) amino groups. APIB-POSS had the least strongly pronounced effect, since it could form covalent bonds with the CER network only by a reaction of one -NH2 group, while AEAPIB-POSS displayed the most highly marked effect, since it could easily be incorporated into the CER network via a reaction of -NH2 and -NH- groups with -O-C≡N groups from CER.

Mechanical, thermal, and morphological studies of adding POSS reinforcement to the PA6/NBR composites

ABSTRACT In this study, a hybrid nanocomposite made of the polyamide 6 (PA6) and nitrile butadiene rubber (NBR) with polyhedral oligomeric silsesquioxanes (POSS) was prepared and mechanical, thermal, and morphology of nanocomposite were tested. The nanocomposite specimens were prepared through the melt mixing method. Tensile and Charpy impact showed that adding the NBR increases the impact strength while decreasing the tensile strength. However, POSS nanoparticles can improve the weakness of adding NBR rubber to the PA6. Additionally, traditional analytical techniques, including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), and scanning electron microscopy (SEM) were conducted.

Effects of Hybrid POSS Nanoparticles on the Properties of Thermoplastic Elastomer-Toughened Polyamide 6.

In this study, polyamide 6 (PA6)/thermoplastic elastomer (TPE) blends were prepared to decrease the notch sensitivity of PA6 for automotive applications, and the morphological, rheological, mechanical, and thermal properties of PA6/TPE blends, which are partially miscible or immiscible depending on the TPE ratio, were significantly improved in the existence of polyhedral oligomeric silsesquioxane (POSS) nanoparticles with multiple reactive epoxy groups as compatibilizers. An unstable phase morphology was obtained with the addition of TPE into PA6 without POSS nanoparticles, whereas interfacial interactions between phases in the presence of POSS were enhanced as a result of a significant decrease in the average particle size from 1.39 to 0.41 μm. The complex viscosity value of the 70PA6/30TPE blend, which was 20 kPa/s-1 at 0.1 rad/s angular frequency, reached 380 kPa/s-1 with the addition of POSS due to the formation of long chains by the generation of graft and/or block copolymers, which resulted in a 65% increase in Young's modulus value. Most notably, the Izod impact strength of pure PA6, which was 10 kJ/m2, increased by 290% with the incorporation of POSS. It was confirmed by FTIR analysis that the reactive multiple epoxy groups of MultEpPOSS and EPPOSS nanoparticles react with the proper groups of PA6 and/or TPE, and also, a partial hydrogen bonding interaction occurs between PA6-TPE from the shifting of N-H and carbonyl peaks. In conclusion, it can be suggested that POSS nanoparticles can serve as highly effective compatibilizers for PA6/TPE blends and have potential commercial applications, especially in the automotive sector.

Effect of polyhedral oligomeric silsesquioxane (POSS) nanoparticle on the miscibility and hydrogen bonding behavior of CO2 based poly(cyclohexene carbonate) copolymers

BackgroundSince the Industrial Revolution in the 1890s, cities have grown exponentially, leading to a significant increase in carbon dioxide emissions and contributing to a growing global environmental crisis. Carbon dioxide capture and storage alone cannot fully address the issue of carbon cycle imbalance. One promising approach is to convert carbon dioxide into polycarbonate polymer, which possesses good biodegradability and is considered a viable alternative to petroleum-based polyester. MethodsIn this experiment, poly(cyclohexene carbonate) copolymer containing polyhedral oligomeric sesquioxane (PCHCPOSS) was prepared using ring-opening copolymerization (ROCOP) method. By mixing it with poly(vinyl phenol) (PVPh), we can observe the forces both intramolecular and intermolecular hydrogen bonding interaction. Significant FindingsThe binary blend of PVPh/PCHCPOSS10 exhibits a single Tg value throughout the composition, indicating complete miscibility. When the proportion of POSS increases, these blends show two different Tg values, suggesting that the addition of POSS does not promote miscibility. The FTIR results indicate that POSS reduces the formation of intermolecular hydrogen bonding interaction. This is attributed to the screening effect in the PVPh/PCHCPOSS binary blend, which significantly diminishes the formation of hydrogen bonds between OH and O=C.

Intermediate Polymer Relaxation Explains the Anomalous Rheology of Nanocomposites with Ultrasmall Attractive POSS Nanoparticles.

The rheological properties of entangled polymers loaded with very small, strongly attractive polyhedral oligomeric silsesquioxane (POSS) fillers differ from that of nanocomposites with larger fillers by (1) the shorter breadth of the entanglement plateau and (2) the relatively unchanged terminal viscosity with increasing POSS loading. Although such anomalous rheological properties can rewrite the property-processing map of materials (e.g., high glass transition temperature and low viscosity), their mechanism remains unclear. In this study, we report that polymer relaxations on intermediate time scales between α and entire-chain relaxation, so-called "slower processes", are responsible for this unusual rheological behavior of poly(2-vinylpyridine)/octa(aminophenyl)silsesquioxane (P2VP/OAPS) nanocomposites. To uncover the effects of entanglements on the nanocomposite dynamics, rheometry is used for variable matrix molecular weights. Results show a systematic change in the rheological response, which is independent of the molecular weight, and in turn, the presence of entanglements. This supports a physical interpretation that a slower process dominates the rheological response of the material at intermediate frequencies on length scales larger than the segment length or the OAPS diameter, while the underlying physical time scales associated with the entanglement relaxation remain unchanged. Such insights are anticipated to assist the future rational design of other highly attractive and ultrasmall nanoparticles that enable a fine-tuned rheological response of nanocomposites across multiple length scales.

In situ formation of POSS layer on the surface of polyimide film and anti-atomic oxygen of SiO2/POSS coatings

Polyhedral oligomeric silsesquioxane (POSS) nanoparticles have attracted wide attention due to their unique capability to reinforce polymers. However, if POSS cannot be uniformly dispersed in the polymer matrix, the desired properties of composites will be reduced. To solve this problem, a method of in situ formation of POSS layer on the surface of polyimide (Kapton) was explored, which not only kept the original properties of polymer unaffected, but also endowed the composites with new properties. The Kapton film completely wetted by γ-aminopropyltriethoxysilane (APTES) was placed in a solution containing tetraethylammonium hydroxide (TEAOH) catalyst, and a POSS layer was gradually grown on the Kapton surface. Subsequently, SiO2 coating was deposited on the surface of POSS layer by magnetron sputtering to prepare SiO2/POSS/Kapton (SPK) samples. FTIR and XPS analyses showed that a layer with POSS structure was formed on the surface of Kapton after 6 h self-growth. Atomic oxygen irradiation test shows that the erosion rate of 6 h SPK sample is 0.19 × 10−24 cm3/atom, only equivalent to 6.0 % of original Kapton, which improves the corrosion resistance of polymer materials.

Unlocking the Potential Use of Reactive POSS as a Coagent for EPDM/PP-Based TPV.

Thermoplastic vulcanizates (TPVs) are multifunctional materials consisting of two or more phases with solid elastomeric properties at room temperatures and fluid-like properties above their melting point. They are produced through a reactive blending process known as dynamic vulcanization. The most widely produced TPV type is ethylene propylene diene monomer/polypropylene (EPDM/PP), which is the focus of this study. The peroxides are mainly selected to be used in crosslinking of EPDM/PP-based TPV. However, they still have some disadvantages, such as the side reactions resulting in the beta chain scission of the PP phase and undesired disproportionation reactions. To eliminate these disadvantages, coagents are used. In this study, for the first time, the use of vinyl functionalized polyhedral oligomeric silsesquioxane (OV-POSS) nanoparticles was investigated as a potential coagent in EPDM/PP-based TPV production via peroxide-initiated dynamic vulcanization. The properties of the TPVs having POSS were compared with the conventional TPVs containing conventional coagents, such as triallyl cyanurate (TAC). POSS content and EPDM/PP ratio were investigated as the material parameters. Mechanical properties of EPDM/PP TPVs exhibited higher values in the presence of OV-POSS, which resulted from the active participation of OV-POSS into the three-dimensional network structure of EPDM/PP during dynamic vulcanization.

Multifunctional Layer-by-Layer Coating Based on a New Amphiphilic Block Copolymer via RAFT-Mediated Polymerization-Induced Self-Assembly Process.

In this hi-tech world, the "smart coatings" have sparked significant attention among materials scientists because of their versatile applications. Various strategies have been developed to generate smart coatings in the past 2 decades. The layer-by-layer (LbL) technique is the most commonly employed strategy to produce a smart coating for suitable applications. Here, we present a smart coating with healing, antifogging, and fluorescence properties fabricated by the LbL assembly of an anionic amphiphilic block copolymer latex and cationic inorganic POSS (polyhedral-oligomeric-silsesquioxane) nanoparticles. In this case, a new anionic block copolymer (BCP), {poly(sodium styrene sulfonate)-block-poly[2-(acetoacetoxy)ethyl methacrylate]}, (PSS-b-PAAEMA) was synthesized via surfactant-free RAFT-mediated emulsion polymerization using the PISA technique. The PSS-b-PAAEMA was characterized by 1H NMR, dynamic light scattering, scanning electron microscopy, and transmission electron microscopy analyses as well as by UV-vis and photoluminescence spectroscopy. For LbL coating fabrication, an amine-modified glass was successively dipped in the anionic latex and cationic POSS solution. The transparent coating exhibited good fluorescence properties under UV light (blue color). The antifogging performance of the coating was also investigated using both cold-warm and hot-vapor techniques. Additionally, the coating surface showed a significant healing activity with a healing efficiency of >75% through ionic interaction. Thus, this finding provides a simple low volatile organic compound (VOC) water-based LbL coating with multifunctional properties that can be a potential material for versatile applications.

Synergistic enhancement of interfacial and anti-hydrothermal properties of HMCF reinforced Cyanate Ester composites by matrix stiffening and interphase optimization

Cyanate ester (CE) matrix and high-modulus carbon fiber (HMCF) surface were modified by epoxy-functionalized polyhedral oligomeric silsesquioxane (POSS), and the correlations of stiffened matrix and optimized interphase with interfacial and anti-hydrothermal properties of various HMCF/CE composites were investigated. The improved tensile modulus and reduced free volume contributed to decreasing coefficient of thermal expansion (CTE) of POSS-CE (PCE) matrix, and a layer of POSS nanoparticles on fiber surface caused the enhancement of surface chemical activity and roughness of POSS-HMCF (P-HMCF), which resulted in 30.9%, 48.9% and 79.8% increment of interfacial shear strength (IFSS) in P-HMCF/PCE composites from the broader modulus intermediate layer, compared to HMCF/CE, HMCF/PCE and P-HMCF/CE composites. After aging 30 days, P-HMCF/PCE composites exhibited the minimum moisture uptake (0.80%) and the highest interlaminar shear strength (ILSS) retention (84.9%), and thickness broadening and cracks propagation at interphase were hardly generated based on the quantitative analysis of interphase modulus distribution, which was attributed to suppressive moisture uptake of PCE matrix and superior interfacial adhesion between resin and P-HMCF.

Polyhedral Oligomeric Silsesquioxane-Based Nanoparticles for Efficient Chemotherapy of Glioblastoma.

Glioblastoma (GBM) is the most common lethal brain tumor with dismal treatment outcomes and poor response to chemotherapy. As the regulatory center of cytogenetics and metabolism, most tumor chemotherapeutic molecules exert therapeutic effects in the nucleus. Nanodrugs showing the nuclear aggregation effect are expected to eliminate and fundamentally suppress tumor cells. In this study, a nanodrug delivery system based on polyhedral oligomeric silsesquioxane (POSS) is introduced to deliver drugs into the nuclei of GBM cells, effectively enhancing the therapeutic efficacy of chemotherapy. The nanoparticles are modified with folic acid and iRGD peptides molecules to improve their tumor cell targeting and uptake via receptor-mediated endocytosis. Nuclear aggregation allows for the direct delivery of chemotherapeutic drug temozolomide (TMZ) to the tumor cell nuclei, resulting in more significant DNA damage and inhibition of tumor cell proliferation. Herein, TMZ-loaded POSS nanoparticles can significantly improve the survival of GBM-bearing mice. Therefore, the modified POSS nanoparticles may serve as a promising drug-loaded delivery platform to improve chemotherapy outcomes in GBM patients.

Characterization of Octa-aminopropyl polyhedral oligomeric silsesquioxanes (OA-POSS) nanoparticles and their effect on sweet basil (Ocimum basilicum L.) response to salinity stress

Salt stress is of the most detrimental abiotic stress factors on either crop or non-crop species. Of the strategies employed to boost the performance of the plants against harmful impacts of salt stress; application of novel nano-engineered particles have recently gained great attention as a promising tool. Octa-aminopropyl polyhedral oligomeric silsesquioxanes nanoparticles (OA-POSS NPs) were synthesized and then a foliar-application of OA-POSS NPs were carried out on sweet basil plants subjected to the salt stress. In that context, interactive effects of OA-POSS NPs (25, 50 and 100 mg L−1) and salinity stress (50 and 100 mM NaCl) were assayed by estimating a series of agronomic, physiological, biochemical and analytical parameters. OA-POSS NPs decreased the harmful effects of salinity by increasing photosynthetic pigment content, adjusting chlorophyll fluorescence, and triggering non-enzymatic (phenolic content) and enzymatic antioxidant components. The findings suggested that 25 mg L−1 OA-POSS NPs is the optimum concentration for sweet basil grown under salt stress. Considering the essential oil profile, estragole was the predominant compound with a percentage higher than 50% depending on the treatment. In comparison to the control group, 50 mM NaCl did not significantly affect estragole content, whilst 100 mM NaCl caused a substantial increase in estragole content. Regarding OA-POSS NPs treatments, increments by 16.8%, 11.8% and 17.5% were observed following application with 25, 50 and 100 mg L−1, respectively. Taken together, the current study provides evidence that POSS NPs can be employed as novel, ‘green’ growth promoting agents in combating salt stress in sweet basil.

Efficient, Robust, and Flame-Retardant Electrothermal Coatings Based on a Polyhedral Oligomeric Silsesquioxane-Functionalized Graphene/Multiwalled Carbon Nanotube Hybrid with a Dually Cross-Linking Structure.

Graphene electrothermal coatings have attracted considerable attention in recent years due to their important application prospects in a broad range of areas. So far, lots of strategies have been explored for producing them. However, these strategies usually involve a complicated process with sophisticated conditions, limiting their scalable applications. Herein, we demonstrate a facile strategy for preparing efficient, robust, and flame-retardant electrothermal coatings from liquid-phase exfoliated graphene, by combining with multiwalled carbon nanotubes (MWCNTs) and polyhedral oligomeric silsesquioxane (POSS) nanoparticles. This relies on the use of a hyperbranched polyethylene copolymer that simultaneously bears UV-reactive moieties and POSS terminal groups. As a stabilizer, the copolymer can effectively promote the exfoliation of both graphite and MWCNTs in common organic solvents under sonication, rendering the POSS-functionalized graphene and MWCNTs well dispersible in the solvent. From their dispersions, POSS-functionalized graphene/MWCNT hybrid electrothermal coatings have been successfully prepared simply by vacuum filtration and UV irradiation under mild conditions. It has been confirmed that a dually cross-linking structure can be formed in the hybrid system. This significantly improves the thermal resistance of resultant coatings, which remain exhibiting a stable work state even at a temperature high as 280 °C without the occurrence of flammation. Meanwhile, this also endows them with excellent electrothermal performance and service stability. At a relatively low voltage, 15 V, the steady temperature can reach 188.4 °C, with a response time < 30 s; after being alternately folded for 2700 cycles or scraped 200 times, the coating still maintains a stable state. In particular, the process involved is relatively simple with mild conditions. With these features, the coatings obtained herein may find their important applications in the area of wearable devices and household heating systems.

Poly(lactic acid) films reinforced with hybrid zinc oxide‐polyhedral oligomeric silsesquioxane nanoparticles: Morphological, mechanical, and antibacterial properties

AbstractNanoparticles of zinc oxide (ZnO), polyhedral oligomeric silsesquioxane (POSS), and their hybrids were added to polylactic acid (PLA) using solution casting process at different weight percentages of the nanoparticles (1, 3, and 5 wt%) to form developed nanocomposites for food packaging applications. According to FTIR and XRD studies, both nanoparticles displayed fair chemical interactions with the PLA matrix. Furthermore, morphological investigations (SEM‐EDS) revealed that POSS, ZnO, and their hybrids were uniformly dispersed into the matrix despite some microaggregations at 5 wt% of nanoparticles, especially for those containing POSS. Moreover, adding 1 wt% of POSS to PLA increased its tensile strength and modulus by 20% and 149%, respectively, while decreasing the elongation‐at‐break by 54%. In addition, the tensile strength, tensile modulus, and elongation‐at‐break of PLA all increased by 7.5%, 28.7%, and 162%, respectively, with the addition of 1 wt% ZnO. Contact angle and surface free energy experiments demonstrated that after incorporating ZnO and POSS into the PLA matrix, the hydrophobicity of the samples increased, and POSS nanoparticles could minimize bacterial adherence effectively. In addition to the antibacterial properties of ZnO and POSS nanoparticles, increasing the concentration of hybrid nanoparticles up to 5 wt% expanded the bacteria's inhibitory zone, particularly in the case of Gram‐positive bacteria (Staphylococcus aureus). Finally, the hybrid nanocomposites exhibited both balanced mechanical characteristics and promising antibacterial activity compared with those with ZnO and POSS alone.

Chitosan/POSS Hybrid Hydrogels for Bone Tissue Engineering.

Hybrid hydrogels composed of chitosan (CS) have shown great potential in bone tissue engineering and regeneration. The introduction of polyhedral oligomeric silsesquioxanes (POSS) in the biopolymeric matrix has been demonstrated to improve the rheological and biological properties of the hybrid composites. In this work, we have integrated the favourable features of chitosan (CS) and POSS nanoparticles to design new nanocomposites for bone tissue regeneration, focusing our attention on the effect of POSS concentration within the CS matrix (0.5, 1, and 1.5 equivalents in weight of POSS with respect to CS) on the chemical, physical, rheological, and in vitro biological properties of the final composites. The drug release ability of the synthesized hydrogel scaffolds were also investigated using, as the model drug, ketoprofen, that was included in the scaffold during the gelling procedure, showing a more controlled release for the hybrids with respect to CS (86-91% of drug released after two weeks). The results of the in vitro biological tests performed on human fetal osteoblastic cells (hFOB 1.19) culture demonstrated the great biocompatibility of the hybrid materials. The hybrids, at the different POSS concentrations, showed values of cell mortality superimposable with control cells (11.1 vs. 9.8%), thus revealing the CS/POSS hydrogels as possible candidates for bone tissue engineering applications.