Inorganic Polyhedral Oligomeric Silsesquioxane Research Articles

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.

Interphase Building of Organic-Inorganic Hybrid Polymer Solid Electrolyte with Uniform Intermolecular Li+ Path for Stable Lithium Metal Batteries.

Lithium (Li) metal has been generally noticed as the most prospective anode for next-generation batteries attributed to its outstanding theoretical capacity and low electrochemical potential. Nevertheless, the unstable solid-electrolyte interphase (SEI) and uncontrollable dendrite growth cause poor reversibility and fetter the practical application of Li metal anodes. Herein, a new organic-inorganic hybrid polymer artificial SEI (POSS-LiBMAB) layer with uniform lithium-ion paths at a molecular level is designed to stabilize Li metal anodes. The SEI layer is constructed by the thiol-ene "click chemistry" reaction between inorganic polyhedral oligomeric silsesquioxane containing eight-mercaptopropyl (POSS-SH) with lithium bis (allylmalonato) borate (LiBMAB) on Li foil. What is more, the POSS-LiBMAB film can be cross-linked and self-reinforced via intermolecular SC bonds. Benefiting from its flexible polymeric covalent structure and noble inorganic Si8 O16 -type cubes, the organic-inorganic hybrid polymer layer is flexible and effectively tolerates the volume change of Li metal anodes during plating/stripping cycles. In addition, this layer shows loose and uniformly distributed electrostatic interaction between Li+ and charge delocalized sp3 boron-oxygen anions, which aids to form a uniform intermolecular Li+ path regulating the homogeneous distribution of Li+ flux on Li anodes. Finally, the designed POSS-LiBMAB layer has high ionic conductivity and lithium-ion transference number, which can effectively promote Li+ diffusion and guide Li deposition beneath the SEI layer. Therefore, with the protection of the POSS-LiBMAB layer, the Li metal anode exhibits stable cycling at 5mA cm-2 for more than 1000 h, and the LFP//Li full cells also present outstanding cycling stability.

Development of Flame Retarding Separator for Lithium Ion Battery By Crosslinkable Binder Coating

Conventional polyolefin separators undergo thermal shrinkage under abnormal conditions such as overcharging and overheating, and this may induce catastrophic thermal runaway in LIBs, resulting in gas venting, fire, rupture, or explosion. Ceramic-coated separators (CCSs) have been widely used because inorganic materials with high heat resistance protect the polyolefin surface to prevent thermal shrinkage of the separator. However, without the use of highly adhesive and thermally stable polymeric binders, the ceramic coating layer is incapable of functioning properly to maintain the thermal stability of the CCSs when exposed to heat.As one method for securing the thermal stability of the separator, we propose crosslinking of the binder in the ceramic coating layer. This study presents a thermally stable crosslinkable silsesquioxane-based ceramic-coated separator (x-CCS) with flame-retarding capabilities for the fabrication of safe Li-ion batteries. The binder used for crosslinking is ePOSS (inorganic polyhedral oligomeric silsesquioxane with epoxy functional end groups) with high thermal stability, which can form crosslinks with each other through UV irradiation. The x-CCS was fabricated by applying a 3 μm thick composite layer of Al2O3/ePOSS/PVdF-HFP to both sides of a conventional polyethylene separator. This remarkably improved the thermal stability of the separator at 140°C, with the original form of the separator maintained even after an ignition test. Because ePOSS, which has high thermal stability, is crosslinked like a net in the coating layer and maintains its shape after combustion. Although the permeability of the CCS was slightly decreased by the applied coating, the resultant improved wettability towards liquid electrolyte thereby enhancing the ionic conductivity, cycle performance, and rate capability when used in a Li-ion battery.

Novel Bulky Lithium Salts and Their Electrolytes for Safer Solid-State Lithium Metal Battery

In recent years, Lithium metal batteries (LMBs) have gained great interests thanks to their high capacity that can respond to the continuous increasing need for energy storage and device. The design and development of new solid-state electrolytes e.g. polymer based ones (SPEs) then became crucial towards intrinsically safer LMBs. A successful electrolyte candidate needs to fulfill several requirements such as high transference number (tLi +) and a compromise between two antagonist properties: conductivity and mechanical properties. Most researches focused on the synthesis of single-ion conducting electrolytes as a strategy to overcome these difficulties1,2. However, these materials often require complicated and delicate chemistry and their conductivity often remains low (σ < 10-5 S/cm at 60°C). An alternative promising route that received much less attention is the development of bulky Lithium salts with macroanion. The bulky anion reduces ion paring and salts aggregation and present negligible mobility compared to Lithium cation resulting in higher transference number3.In this work, we present a new macroanion based on Polyhedral Oligomeric Silsesquioxane (POSS) grafted with either polyethylene oxide oligomers (PEG) and/or Lithium sulfonyl (trifluoromethanesulfonyl) imide (LiTFSI) denoted as POSS-LiTFSI-PEG or POSS-LiTFSI respectively. Thus, SPE has been prepared with a reference high molecular weight polyethylene oxide at different OE/Li ratio from 10 to 25. This new concept of bulky multi-anion based on TFSI moieties allows a complete salt dissociation, an enhancement of the mechanical properties thanks to the presence of the inorganic POSS multi anions that play the role of nano fillers, and finally, a strong increase of the Li+ transference number (tLi+>0,55), which opens many perspectives. The cycling performance obtained in both Lithium symmetric cells and LMBs prototypes will be also presented.References(1) Bouchet, R.; Maria, S.; Meziane, R.; Aboulaich, A.; Lienafa, L.; Bonnet, J.-P. P.; Phan, T. N. T.; Bertin, D.; Gigmes, D.; Devaux, D.; et al. Single-Ion BAB Triblock Copolymers as Highly Efficient Electrolytes for Lithium-Metal Batteries. Nat. Mater. 2013, 12 (5), 452–457.(2) Zhang, H.; Li, C.; Piszcz, M.; Coya, E.; Rojo, T.; Rodriguez-Martinez, L. M.; Armand, M.; Zhou, Z. Single Lithium-Ion Conducting Solid Polymer Electrolytes: Advances and Perspectives. Chem. Soc. Rev. 2017, 46 (3), 797–815.(3) Chinnam, P. R.; Wunder, S. L. Polyoctahedral Silsesquioxane-Nanoparticle Electrolytes for Lithium Batteries: POSS-Lithium Salts and POSS-PEGs. Chem. Mater. 2011, 23 (23), 5111–5121. Figure 1

Daunorubicin-silsesquioxane conjugates (POSS-DAU) for theranostic drug delivery system: Characterization, biocompatibility and drug release study

In this study, we describe the synthesis, physicochemical characterization and in vitro results of the evaluation of the biological behaviour of multifunctional nanoplatform based on inorganic polyhedral oligomeric silsesquioxane (POSS) grafted with antracycline antibiotics (daunorubicin, DAU) and/or short poly (ethylene glycol) chains (PEG). A high-efficient synthetic route is used to obtain soluble POSS-DAU and PEG-POSS-DAU conjugates. The POSS cage is activated by attachment of the anhydride rings and thus formed octakis-[3-(2-succinic anhydride)propyl, dimethylsiloxy]octasilsesquioxane (POSSAN) reacts with amino group of daunorubicin or methoxy-PEG. The chemical structure of conjugates is confirmed by 1H, 13C NMR and HRMS analyses. In vitro anticancer cytotoxic activity is compared for (i) full-substituted POSS (POSS-DAU8), (ii) partially substituted POSS (POSS-DAU3) and (iii) POSS with mixed substituents (mPEG4-POSS-DAU3) in HeLa cells using the MTT assay. The ability to intercalate into DNA strains is confirmed by gel electrophoresis method.

Facile preparation and properties of polyhedral oligomeric silsesquioxane (POSS) nano-hybrid materials with disaggregation effect

This work reports on a facile and efficient strategy for preparing a class of chromophores- including organic-inorganic functional hybrid materials. These hybrid materials are based on pyrene and octavinyl-polyhedral oligomeric silsesquioxane (OV-POSS), in which the positive vinyls in OV-POSS were heck coupling reacted with pyrenes. It was found that the incorporation of polyhedral oligomeric silsesquioxane (POSS) can significantly precluded aggregation of hybrid molecules due to the inhibition of π-π stacking between chromophore units, which were also further confirmed by theoretical simulation. Moreover, the fluorescence quantum efficient of H2 (Φsolid = 80%) is higher than H1 (Φsolid = 65%) and H3 (Φsolid = 68%), respectively. AFM and OM images showed the smooth surface structure of the hybrid film, which demonstrated that the incorporation of inorganic POSS could improve the film-forming property of organic chromophores. Simultaneously, thermogravimetric analysis (TGA) results also display inorganic POSS core leads to the good thermal stabilities (>250 °C) of the functional hybrids materials.

Transparent, High Glass-Transition Temperature, Shape Memory Hybrid Polyimides Based on Polyhedral Oligomeric Silsesquioxane

Optically transparent polyimides with excellent thermal stability and shape memory effect have potential applications in optoelectronic devices and aerospace industries. A series of optically transparent shape memory polyimide hybrid films are synthesized from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and 2,2′-bis-(trifluoromethyl)biphenyl-4,4′-diamine (TFMB) with various polyhedral oligomeric silsesquioxane (POSS) contents and then subjected to thermal imidization. The hybrid films show good optical transparency (>80% at 400 nm and >95% at 500 nm) with cutoff wavelengths ranging from 318 to 336 nm. Following the incorporation of the inorganic POSS structure, the hybrid films exhibit excellent thermal stability with glass transition temperature (Tg) ranging from 351 to 372 °C. The hybrid films possess the highest Tg compared with the previously-reported shape memory polymers. These findings show that POSS is successfully utilized to develop transparent polyimides with excellent thermal stability and shape memory effect.

Crosslinkable polyhedral silsesquioxane-based ceramic-coated separators for Li-ion batteries

Inorganic polyhedral oligomeric silsesquioxane with epoxy functional groups (ePOSS) is newly presented as a co-binder for the ceramic-coated separator (CCS) for safe Li-ion batteries. The ePOSS-incorporated coating layer significantly improved the dimensional stability of the CCS at 140°C and maintained the original form even after an ignition test. Although the permeability of the CCS was slightly decreased due to the crosslinked structure of the silsesquioxane coating layer, it showed high electrochemical stability up to 5V. Moreover, the improved liquid electrolyte wettability by ePOSS co-binder enhanced the ionic conductivity and showed 93% of cycle capacity at 0.5C rate in Li-ion batteries.

Synthesis of Janus POSS star polymer and exploring its compatibilization behavior for PLLA/PCL polymer blends

Synthesis of hybrid hetero-arms star polymer with precisely defined arms distribution in three dimensional (3D) space is still a challenge. Herein, we have employed cubic polyhedral oligomeric silsesquioxane (POSS) nanoparticle as a scaffold to synthesize a biodegradable Janus POSS star polymer (oom-T8PLLA5PCL3), which contains an inorganic rigid POSS core, three poly(ε-caprolactone) (PCL) arms and five poly(l-lactide) (PLLA) arms on the POSS cage two sides, respectively. The chemical structure of oom-T8PLLA5PCL3 was confirmed by NMR, SEC, and FTIR spectra. As an example of application for the Janus POSS star polymer, oom-T8PLLA5PCL3 was used for the compatibilization of biodegradable PLLA/PCL (w/w = 70/30) blends. It was found that oom-T8PLLA5PCL3 could reduce the dispersed PCL phase size in PLLA matrix and enhance the properties of PLLA/PCL polymer blends, which was reflected in the increase of Izod impact strength and tensile performance of the polymer blends.

Structural analysis of dendrimers based on polyhedral oligomeric silsesquioxane and their assemblies in solution by small-angle neutron scattering: Fits to a modified two correlation lengths model

The small-angle neutron scattering (SANS) technique has been used to investigate the structure of dendrimers based on polyhedral oligomeric silsesquioxane (POSS) in solution. Three generations and two distinct terminal groups (either vinyl or polyethylene glycol (PEG) terminal groups) as well as four concentrations for each dendrimer have been measured in deuterated tetrahydrofuran. Two main scattering regimes, one with a length scale of nm and the other with a length scale of sub-micron, are found to contribute to the SANS signals. In order to fit the SANS data, a new modified two correlation lengths model has been developed. Fit parameters include scale factors, correlation lengths, Porod exponents and “particle” elongation parameters. Our fit results show that the local structure does not correspond to single dendrimer molecules, but rather to POSS-rich domains surrounded by POSS-poor domains. The large-scale structure represents the overall morphology of multi-dendrimer aggregates. The flexible PEG outer links help to enhance the stability of inorganic POSS cages, and allow the hybrid polymers to adjust their conformation in order to respond to their surroundings. With increasing concentration, the local structure becomes more compact as evidenced by the decrease of correlation length and concurrent increase of the Porod exponent. The deformation of local structure during the compaction process is also observed. The structure becomes elongated at intermediate concentrations whereas it tends to be more globular at low and high concentrations.

Biomimetic and nanostructured hybrid bioactive glass

Inspired by nature's toughening mechanisms, we designed a new polyhedral oligomeric silsesquioxane (POSS)-derived hybrid glass (PHG) that has covalent interactions on the molecular scale between the inorganic POSS cage and organic phase. These features allow “elastic deformation” of the inorganic POSS cage in limited scale. The final product is a bulk hybrid material with toughness (3.56 ± 0.25 MPa·m1/2) similar to natural bone (2.4–5.3 MPa·m1/2). PHG exhibited excellent bioactivity by promoting the formation of plate-like hydroxyapatite on its surface in simulated body fluid and showed good cell adhesion. PHG also can be a platform to guide adipose tissue-derived mesenchymal stem cells differentiation and mineralization. The key structural features of this material can be used to guide the design of bio-inspired composites with unique toughness, which would be of great benefit to hard tissue engineering.

Tailor‐Made Hybrid Organic–Inorganic Porous Materials Based on Polyhedral Oligomeric Silsesquioxanes (POSS) by the Step‐Growth Mechanism of Thiol‐Ene “Click” Chemistry

Clicking 3D materials: Hybrid, organic–inorganic polyhedral oligomeric silsesquioxane precursors are woven into macroscopically shaped entities by thiol-ene chemistry in a radical-mediated, step-growth fashion, by photo or thermal initiation (see figure). The materials are nanostructured and their macroporous features and physical properties are easily tailored.

Star-shaped inorganic–organic hybrid polymers with polyhedral oligomeric silsesquioxane core: Synthesis, self-assembly and tunable thermoresponse

A series of novel star-shaped hybrid P(2-(2-methoxyethoxy)ethylmethacrylate)-co-oligo(ethylene glycol) methacrylate (P(MEO2MA-co-OEGMA)) polymers with polyhedral oligomeric silsesquioxane (POSS) core (POSS-(P(MEO2MA-co-OEGMA))8) were synthesized via atom transfer radical polymerization (ATRP). The obtained inorganic–organic hybrid polymers can self-assemble into micelles in aqueous solution owing to the amphiphilic property resulting from the hydrophobic inorganic POSS core and the hydrophilic P(MEO2MA-co-OEGMA) segments. The hybrid polymeric micelles show a significant tunable temperature responsive property which can be adjusted from 29.7 to 39.1°C through altering the ratio of MEO2MA and OEGMA in P(MEO2MA-co-OEGMA) polymers. These amphiphilic hybrid polymers have potential applications in nano-carrier, nano-reactor, smart materials and biomedical fields.

Synthesis of peptide dendrimers with polyhedral oligomeric silsesquioxane cores via click chemistry

Abstract Inorganic polyhedral oligomeric silsesquioxane (POSS) was used as the core for the synthesis of poly( l -lysine) peptide dendrimer via copper-catalyzed azide–alkyne click chemistry. The inorganic/organic composite dendrimer was characterized by MS, 1H NMR, FTIR, GPC and DLS.

A generic and effective strategy for highly effective “intrinsic” molecular luminescence in the condensed state

A generic and efficient strategy to realize a high effective “intrinsic” single molecular luminescence in the condensed state was proposed by theoretical simulation at the macrostructure level at first, and then was confirmed by molecular design and preparation of a dumbbell-type (H2) and tadpole-type (H1) polyhedral oligomeric silsesquioxane (POSS) based hybrid. The enhancement mechanism of the optical properties was investigated in theory and with experiments. It was found that the incorporation of a “huge” inorganic POSS core on the nanoscale into the organic light-emitting molecules to form three-dimensional (3D) organic–inorganic hybrids effectively improved the optical properties in the condensed matter by decreasing the intermolecular dipole–dipole and π–π stacking interactions owing to the hindrance of the intermolecular charge-transfer between adjacent organic molecules. The dumbbell-type hybrid (H2) showed a better enhancement effect of the optical properties than the resultant tadpole-type hybrid (H1) owing to the crisscross-type arrangement of its dimer induced by the incorporation of POSS. Simultaneously, the two hybrids exhibited high thermal stability and good film forming ability.

Synthesis and thermal stability of star polymer with eight arms using polyhedral oligomeric silsesquioxane as a core

AbstractA Polyhedral oligomeric silsesquioxane (POSS) containing eight 3- chloropropyl groups was synthesized and incorporated into poly(methyl methacrylates) to form star polymer. First, octa(3-chloropropyl) POSS [(ClCH2CH2CH2)8Si8O12] was prepared by hydrolysis and condensation of 3- chloropropyltriethoxysilane, and then two star-shaped POSS/PMMA composites with different POSS content was synthesized at 110 °C, using octa(3-chloropropyl) POSS as an multifunctional initiator, CuCl and 2-2’ bipyridine (Bpy) as catalyst system. The structures of octa(3-chloropropyl) POSS and star-shaped POSS/PMMA composite were characterized by analytical methods including FTIR, NMR, GPC and XRD, with results showing that POSS molecule was successfully formed which accorded well with the reported work and was dispersed into PMMA matrix evenly by atom transfer radical polymerization method. The TGA results indicated that synthetic POSS molecule possessed good thermal stability, and the thermal stability of POSS/PMMA composite enhanced with the increase of POSS content, which is due to the incorporation of inorganic POSS molecule

Hydrolytic degradation of POSS–PEG–lactide hybrid hydrogels

A polyhedral oligomeric silsesquioxane (POSS), functionalized with eight arms of poly(ethylene glycol) (PEG; MW 400) and then acrylated, was incorporated into a hydrogel network based on triblock copolymers of poly(lactide- b-ethylene glycol- b-lactide) diacrylates using a redox-initiated polymerization. The organic–inorganic hybrid hydrogels so prepared contained the inorganic crosslinker POSS from 1 to 28 wt.%. The degradation properties of the hydrogels in a pH 7.4 phosphate-buffered saline solution at 37 °C were studied using measurements of mass loss, cryogenic SEM, and ATR-FTIR spectroscopy. It was found that copolymerization of acrylated 1kPEG-lactide with increasing amounts of POSS created a more porous network which was more resistant to hydrolysis. The ATR-FTIR technique was used to monitor the progress of degradation with exposure time through the changes in the carbonyl and C–H deformation bands of the lactide and the Si–C stretching band of the POSS. Increasing POSS incorporation resulted in decreased rate of degradation due to its hydrophobic nature and inertness to hydrolysis. Conversely, an increase in lactide content increased the degradation rate due to the increased number of hydrolytically-sensitive ester groups in the network.

POSS-based hybrids by melt/reactive blending

Organic–inorganic polyhedral oligomeric silsesquioxane (POSS)–polymer hybrids have gained a wide research interest in the last decade, thanks to the great versatility of POSS synthesis and availability of different chemical structures, aimed at modifications of physical/chemical properties of polymers or at delivering new functional properties. Traditionally, in situ copolymerisation of POSS to produce hybrid organic–inorganic polymers with pendent POSS groups has been used both for thermoplastics and thermosets. In recent years, attention has been also given to the possibility of preparing POSS–polymer systems by melt blending techniques, taking advantage of (i) miscibility of POSS into polymers thanks to physical interactions or (ii) chemical reaction between POSS and the polymer. These two methods, usually referred to respectively as melt blending and reactive blending, represent very appealing, inexpensive and environmentally friendly processes for industrial development of POSS technology. This paper reviews the present state of the art on both melt blending and reactive blending of POSS into thermoplastic polymers, discussing present achievements and limitations from both methods.

Controllable Preparation and Optical Limiting Properties of POSS-Based Functional Hybrid Nanocomposites with Different Molecular Architectures

A series of soluble polyhedral oligomeric silsesquioxane (POSS) based inorganic−organic hybrid nonlinear optical materials with different architectures, such as dumbbell-type, bead-type and network-type structure, were prepared based on the hydrosilylation addition reaction of multifunctional octahydridosilsesquioxane (T8H) with different azobenzene chromophore monomers. These resultant hybrid composites are soluble in common organic solvents such as tetrahydrofuran, toluene, and chloroform, and exhibit good film-forming ability. Their structures and properties were characterized and evaluated with IR, 1H NMR, 29Si NMR, TGA, DSC, optical limiting measurement and Z-scan technique, respectively. The results show that the structure of these resultant hybrids can be effectively tuned by simply varying the feed ratio and molecular structure of organic chromophore monomers. The incorporation of inorganic POSS into organic azobenzene chromophore has endowed the hybrids with well optical limiting properties and high thermal stability. Simultaneously, the relationship between molecular structure and properties of these hybrids were investigated in detail.

Preparation and properties of ethylene/POSS copolymer with rac‐Et(Ind)2ZrCl2 catalyst

AbstractThe various monovinyl‐functional polyhedral oligomeric silsesquioxane (POSS) monomers had been copolymerized with ethylene (E) using rac‐Et(Ind)2ZrCl2 and a modified methylaluminoxane (MMAO) cocatalyst. The unreacted POSS monomer could be removed completely by washing the copolymerization product with n‐hexane. And the copolymers were characterized with 1H NMR, TEM, DSC, TGA, and GPC to know the composition, thermal properties, molecular weight and its distribution, respectively. According to 1H NMR data, the monomer reactivity ratios of various POSS monomers were calculated by the Fineman‐Ross and Kelen‐Tudos methods. Thermogravimetric analysis of E/POSS copolymers exhibited an improved thermal stability with a higher degradation temperature and char yields, demonstrating that the inclusion of inorganic POSS nanoparticles made the organic polymer matrix more thermally robust. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009