Polyhedral Oligomeric Silsesquioxane Research Articles

Organic–inorganic covalent–ionic network enabled all–in–one multifunctional coating for flexible displays

Touch displays are ubiquitous in modern technologies. However, current protective methods for emerging flexible displays against static, scratches, bending, and smudge rely on multilayer materials that impede progress towards flexible, lightweight, and multifunctional designs. Developing a single coating layer integrating all these functions remains challenging yet highly anticipated. Herein, we introduce an organic–inorganic covalent–ionic hybrid network that leverages the reorganizing interaction between siloxanes (i.e., trifluoropropyl–funtionalized polyhedral oligomeric silsesquioxane and cyclotrisiloxane) and fluoride ions. This nanoscale organic–inorganic covalent–ionic hybridized crosslinked network, combined with a low surface energy trifluoropropyl group, offers a monolithic layer coating with excellent optical, antistatic, anti–smudge properties, flexibility, scratch resistance, and recyclability. Compared with existing protective materials, this all–in–one coating demonstrates comprehensive multifunctionality and closed–loop recyclability, making it ideal for future flexible displays and contributing to ecological sustainability in consumer electronics.

Facile synthesis of polyhedral oligomeric silsesquioxanes with excellent thermosetting, fibrous and crystalline properties

The development of multifunctional polyhedral oligomeric silsesquioxanes (POSS) that are more serialized than traditional POSS is essential to reduce the economic investment and expand the category of high-performance POSS. This work employed a simple one-step method to synthesize a series of different physical states of methacryloxypropyl-phenyl POSS (AcPhPOSS). The FTIR, NMR and MS results showed that the products were mainly composed of regular T8, T10 and T12 cage-like structures, and the outer periphery of the AcPhPOSS cage carried different proportions of flexible methacryloxypropyl (R1) and rigid phenyl (R2) groups. In addition, the curable, fibrous, and crystalline properties of liquid, semi-solid, and powder AcPhPOSS were studied through thermal curing, electrospinning, and crystallization methods, respectively. The results showed that AcPhPOSS in three different states, especially AcPhPOSS@1:0 (liquid), AcPhPOSS@1:3 (semi-solid) and AcPhPOSS@0:1 (powder), exhibited good thermal curing properties, fiber and crystallization, respectively. Hence, this work proposes a facile strategy for producing multifunctional materials with good curing properties, fiber-forming properties, and crystallinity, which have broad application potential in thermosetting resins, fiber materials, and single crystal materials.

The salt removal from ancient sandstone using CaCO3 oligomer- and POSS siloxane-enhanced zwitterionic polymer

The weathering of outdoor sandstone cultural relics was dominantly induced by the circulating crystallization of soluble salt Na2SO4. This work proposed to weaken the salt-induced deterioration by a protective material that could reinforce the fragile sandstone and simultaneously remove the salt via continuously transporting the salt towards the air-sandstone interface without damage to the sandstone. Therefore, a new protective material bearing poly(methacryloyloxylethyl phosphorylcholine) (PMPC)-based zwitterionic polymer segment (PMH), hydrophobic polyhedral oligomeric silsesquioxane (POSS) segment (APTES-POSS) and small-size CaCO3 oligomer was prepared and denoted as POSS-PMH/CaCO3 composite. The presence of phosphorylcholine zwitterionic groups with water/salt affinity contributed greatly to the salt crystallization resistance of POSS-PMH/CaCO3 coating. Specifically, Na2SO4 crystallization pressure in the (POSS-PMH/CaCO3)-coated confined medium decreased by 88.1% and 59.6% as compared with that in the glass plate confined medium and that in the (APTES-POSS)-coated confined medium, respectively. In addition, the salt in (POSS-PMH/CaCO3)-treated sandstone could be ingeniously removed by zwitterion-induced outward transport. As a functional additive to traditional paper pulp poultice, POSS-PMH/CaCO3 could also achieve a high-efficiency extraction of salt from sandstone. More critically, the hydrophobicity and strong interfacial bonding ability of APTES-POSS segment, as well as the small size effect and crosslinking property of CaCO3 oligomer highly facilitated the interfacial adhesion of POSS-PMH/CaCO3 towards sandstone, improving the service life of POSS-PMH/CaCO3 and meanwhile avoiding the potential damage to sandstone during the removal of salt.

Hyaluronic acid-based ε-polylysine/polyurethane asymmetric sponge for enhanced wound healing

Asymmetric sponge dressings with a hydrophobic surface and a hydrophilic inner layer can prevent bacterial infiltration and ensure efficient absorption of wound exudate. In this work, ε-polylysine/aliphatic polyurethane sponge (EPU) was prepared by prepolymer foaming process, and oxidized hyaluronic acid (OHA) was cross-linked with ε-polylysine (EPL) in EPU through schiff-base reaction to obtain EHPU. Octaisobutyl polyhedral oligomeric silsesquioxane (Oi-POSS) was uniformly sprayed onto the surface of EHPU as the hydrophobic layer, resulting in asymmetric sponge dressings denoted as P-EHPU. These dressings demonstrate capabilities in resisting staining and bacterial invasion, with internal EPL effectively inhibiting bacterial proliferation on the wound surface. The introduction of OHA and EPL leads to a denser and more complete pore structure of the sponge, endowing it with good compression, tensile strength, and hemostatic performance. Wound healing studies indicate that P-EHPU effectively prevents external bacterial infiltration and promotes wound healing.

Acid Sensors Based on Luminochromism of Solid‐State Excimer Emission of Pyrene‐Modified Polyhedral Oligomeric Silsesquioxane

To obtain solid‐state fluorescence sensors, it is essential to simultaneously obtain solid‐state emission and stimuli‐responsiveness. In this research, the modified polyhedral oligomeric silsesquioxane (POSS) tethered with pyrenes was synthesized and we confirmed that both demands for developing solid‐state fluorescence sensors can be satisfied. The POSS derivative exhibited strong emission even in the solid state. In particular, we found that exposure of the POSS films to trifluoroacetic acid vapor resulted in a significant red‐shift of the peak wavelength of the emission band. Excitation spectroscopy and comparison with model compounds suggest that this significant red‐shift should be attributable to the formation of static excimer, meaning a preformed dimer in the ground state induced by protonation of the secondary amino groups. These results indicate that POSS is a promising scaffold for a solid‐state fluorescence sensor.

Doped double spirocyclic cationic POSS for nanocomposite anion exchange membranes with high conductivity and robustness

Organic-inorganic hybridization methods are receiving increasing attention as a method that can improve the performance of anion exchange membranes (AEMs) in a simpler and more effective way. Here, by selecting polyhedral oligomeric silsesquioxane (POSS) with good mechanical and thermal properties as inorganic fillers. Successful introduction of N-spirocyclic cations with bifunctional groups onto POSS yielded MDSU-poss. subsequently, we doped them into qPTP-IC-O-9% membranes as fillers in different ratios to obtain a series of composite membranes. High-density cations introduced by POSS with simultaneous organic-inorganic frameworks effectively inhibit membrane over-swelling. As a result, the membrane is able to achieve high ionic conductivity with the assurance of reasonable dimensional stability. At 80 °C, the 15 % MDSU-poss/qPTP-IC-O membrane achieved the ionic conductivity of 168.6 mS cm−1 at low SR with the peak power density of 431 mW cm−2. In addition, the mechanical properties of the composite membranes were all greatly improved due to the organic cations attached to the POSS with good affinity, contributing to the tensile strength of the 15 % MDSU-poss/qPTP-IC-O membrane of 57.4 MPa. The membrane was finally immersed in 3 M NaOH solution for 1032 h and still maintained 89.3 % of the starting ionic conductivity.

Preparation and Characterization of Atomic Oxygen-Resistant, Optically Transparent and Dimensionally Stable Copolyimide Films from Fluorinated Monomers and POSS-Substituted Diamine.

Optically transparent polyimide (PI) films with good atomic oxygen (AO) resistance have been paid extensive attention as thermal controls, optical substrates for solar cells or other components for low Earth orbit (LEO) space applications. However, for common PI films, it is usually quite difficult to achieve both high optical transparency and AO resistance and maintain the intrinsic thermal stability of the PI films at the same time. In the current work, we aimed to achieve the target by using the copolymerization methodology using the fluorinated dianhydride 9,9-bis(trifluoromethyl)xanthene-2,3,6,7-tetracarboxylic dianhydride (6FCDA), the fluorinated diamine 2,2-bis [4-(4-aminophenoxy)phenyl]hexafluoropropane (BDAF) and the polyhedral oligomeric silsesquioxane (POSS)-containing diamine N-[(heptaisobutyl-POSS)propyl]-3,5-diaminobenzamide (DABA-POSS) as the starting materials. The fluoro-containing monomers were used to endow the PI films with good optical and thermal properties, while the silicon-containing monomer was used to improve the AO resistance of the afforded PI films. Thus, the 6FCDA-based PI copolymers, including 6FCPI-1, 6FCPI-2 and 6FCPI-3, were prepared using a two-step chemical imidization procedure, respectively. For comparison, the analogous PIs, including 6FPI-1, 6FPI-2 and 6FPI-3, were correspondingly developed according to the same procedure except that 6FCDA was replaced by 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). Two referenced PI homopolymers were prepared from BDAF and 6FDA (PI-ref1) and 6FCDA (PI-ref2), respectively. The experimental results indicated that a good balance among thermal stability, optical transparency, and AO resistance was achieved by the 6FCDA-PI films. For example, the 6FCDA-PI films exhibited good thermal stability with glass transition temperatures (Tg) up to 297.3 °C, good optical transparency with an optical transmittance at a wavelength of 450 nm (T450) higher than 62% and good AO resistance with the erosion yield (Ey) as low as 1.7 × 10-25 cm3/atom at an AO irradiation fluence of 5.0 × 1020 atoms/cm2. The developed 6FCDA-PI films might find various applications in aerospace as solar sails, thermal control blankets, optical components and other functional materials.

Validation of experimental results for polyhedral oligomeric silsesquioxane, carbon nanotube and functionalized carbon nanotube/polymer nanocomposites through density functional theory study

The mechanical and thermal properties of polymer nanocomposites could be influenced by different parameters. Interfacial interaction between nanomaterial and polymer composite can effectively influence the properties of nanocomposite. In this paper, the interaction between carbon nanotube (CNT), functionalized carbon nanotube with Amin (CNT-Amin), and Polyhedral Oligomeric Silsesquioxane (POSS), absorbing on PA/EVA composite surface theoretically were investigated based on the density functional theory (DFT) calculations. The interaction energy of −36.64 kJ/mol between PA and CNT-Amin and −22.31 kJ/mol between EVA and CNT-Amin means that the absorption of CNT-Amin on PA and EVA monomer are stronger than CNT and POSS which could affect the mechanical and thermal properties of the nanocomposites. However, the interaction between the polymer composite and the nanomaterials was physisorption. Additionally, thermal and mechanical tests were conducted on nanocomposite samples. Thermal and mechanical results show that the DFT calculations are in good agreement with the experiment. DSC analysis shows that the melting temperature for PA in PA/EVA/CNT-Amin changed from 221.6 to 225.2 °C and crystallization temperature from 188.8 to 191.9 °C which illustrates that the CNT-Amin nanomaterial adsorbed to PA in PA/EVA composite. Finally, mechanical properties show that the modulus of PA/EVA/CNT-Amin nanocomposite changed from 307.4 to 327.2 MPa compared to neat PA/EVA composite emphasizing that the interaction between CNT-Amin nanomaterial and PA improves the strength of the nanocomposite and in addition, EVA adsorbs the CNT which affected the strain of the nanocomposite at break by 16 % which corresponds to the calculation result prediction.

Evaluation of the Mechanical Strength and Cell Adhesion Capacity of POSS Doped PVA/CMC Hernia Patch.

Peritoneal adhesion typically occurs in applications such as abdominal, pelvic, and vascular surgery. It is necessary to develop a mechanical barrier to prevent adhesion. In this study, a novel biomaterial as a mechanical barrier is developed by combining polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC), doped with polyhedral oligomeric silsesquioxane (POSS) to prevent peritoneal adhesion. Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) methods reveal that POSS nanoparticles in the PVA matrix disrupted the intramolecular hydroxyl groups and structure of the crystal region. Electron microscopy (EM) images reveal that high concentrations of POSS (2wt.%) cause irregular clustering in the composite matrix. As the concentration of POSS increases in the matrix, the degradation of the membranes increases, and protein adhesion decreases. In vitro cytotoxicity tests show a toxic effect on cells for PVA/CMC composite membranes, while on the other hand, the addition of POSS increases cell viability. According to the MMT test the POSS decreases cell adhesion of membranes. When comparing the POSS doped membrane to the undoped PVA/CMC membrane, an increase in the total antioxidant level and a decrease in the total oxidant level is observed.

Effect of semifluoroalkyl substituents in the POSS on atomic oxygen exposure

Due to the many recent Earth observation missions, very low Earth orbit (VLEO) have become a pressing topic for satellite research. Since the density of atomic oxygen (AO) in VLEO is higher than in low Earth orbit (LEO), the need for AO-resistant materials based on polyhedral oligomeric silsesquioxane (POSS) is strong. However, the effects of the side-chain groups in the POSS on AO exposure are unclear. In this study, we focused on POSS molecules modified with semifluoroalkyl groups as side chains because fluorocarbon groups, such as fluorinated ethylene propylene (FEP), are known to have high AO resistance. Semifluoroalkyl- and alkyl-substituted POSS films were fabricated and exposed to a laser-detonation AO source. Microbalance measurements showed that the mass losses of the semifluoroalkyl-substituted POSS films were larger than those of alkyl-substituted POSS films. X-ray photoelectron spectroscopy measurements showed that the silica layers formed on the semifluoroalkyl-substituted POSS were thicker than on alkyl-substituted POSS films. Surface observation using a field emission scanning electron microscope revealed microscale cracks on the surface of the semifluoroalkyl-substituted POSS. These findings indicate that POSS molecules with fluorine substituents warrant careful consideration of the AO-barrier performance of the silica layer formed during AO exposure.

Enhancing flame retardancy and mechanical strength of glass fiber-reinforced biomass polyamide composites with surface-functionalized black phosphorus

Fiber-reinforced polyamide exhibits exceptional mechanical properties and durability; however, its widespread application is impeded by potential fire hazards. In this study, a hybrid material consisting of black phosphorus (BP) and polyhedral oligomeric silsesquioxane (POSS) was synthesized, denoted as BP-CO-POSS. The fire safety of fiber-reinforced polyamide demonstrated significant enhancement upon the incorporation of aluminum diethyl phosphinate (Alpi) and BP-CO-POSS. This enhancement was evident in various aspects, including the suppression of heat release behaviors, reduction in the emission of toxic gases, and an increase in the UL-94 rating. Notably, with the additional inclusion of 0.5 wt% BP-CO-POSS, a substantial decrease in both heat release rate (31.15 %) and total heat release (37.59 %) was observed when compared to the application of Alpi and BP alone, thus affirming the existence of a synergistic effect. This observation was substantiated through a comprehensive analysis of results obtained from both gas and condensed phases. This study offers a practical methodology for the widespread utilization of phosphorus-rich advanced materials, thereby further enhancing the fire safety of fiber-reinforced polymers.

Exciplex Emission in the POSS Possessing Two Kinds of Luminophores

Here we report the synthesis and luminescent properties of the modified polyhedral oligomeric silsesquioxane (POSS) that possesses two types of luminophores, cyanobenzene and N,N‐diethylaniline for inducing significant emission not only from each dye but also from molecular interactions on the POSS core. From the optical measurements in the diluted solution, we observed both locally‐excited emission and excimer emission originating from intramolecular interactions assisted by POSS. Moreover, highly‐efficient exciplex emission was observed from the thin film, indicating that the interaction between luminophores easily occurs in the solid state by accumulating two kinds of molecules in the single POSS molecule. Finally, we also found that the modified POSS showed a unique acid responsiveness which can be caused by protonation at two types of amino moieties. In this manuscript, it is shown that POSS is able to play various roles at the same time: recruiting excited molecules to form exciplexes, suppressing concentration quenching in the solid state, and imparting stimulus responsiveness to exciplexes.

Polyhedral oligomeric silsesquioxane-modulated mesoporous amorphous bimetallic organic frameworks for the efficient isolation of immunoglobulin G

The efficient and accurate separation of immunoglobulin G (IgG) plays a vital role for disease diagnosis and therapy, but it is always hampered by the huge geometric size and complex structure of IgG. In this work, an amorphous Fe/Co bimetallic organic framework (denoted as PMOF-Fe/Co) is fabricated for IgG separation, with octa-carboxyl polyhedral oligomeric silsesquioxane (OCPOSS) as modulator for the first time. Benefiting from the rigid nanostructure and competitive coordination of OCPOSS, the aperture of PMOF-Fe/Co is enlarged to ∼20 nm along with the generation of enormous structural defects, which enables the accommodation of protein species with high molecular weights and large sizes. OCPOSS is also found exerting a positive impact on mediating the specific recognition and adsorption ability of PMOF-Fe/Co towards IgG through metal affinity, hydrophilic and hydrophobic interactions. Consequently, the multimode and multivalent affinity of PMOF-Fe/Co gives rise to an extraordinary adsorption capacity (2691.7 mg g−1) and satisfactory practical application performance. This study is convinced to provide a simple avenue for the efficient separation of specific large-sized proteins, as well as the engineering of abiotic affinity reagents with compositional and architectural complexity.

Preparation of ultraviolet‐cured silicone elastomer reinforced by SH‐POSS crosslinker for light emitting diode encapsulant

AbstractStable silicone encapsulants are essential for protecting high‐power light‐emitting diodes (LED) from dust and moisture and extending their service life. Herein, by incorporating thiol‐functionalized polyhedral oligomeric silsesquioxane (SH‐POSS) as a crosslinker into ultraviolet‐curable silicone elastomer (UVSE), a series of new UV‐cured silicone encapsulants (SH‐POSS/UVSE) have been developed through thiol‐ene click chemistry. It was found that SH‐POSS effectively enhanced the mechanical properties of SH‐POSS/UVSE. When 30 mol% SH‐POSS was added, the tensile strength and elongation at break reached 1.01 MPa and 422%, respectively, 2.1 and 1.6 times higher than pure UVSE. This could be ascribed to the more concentrated crosslinking network and the improved interfacial interactions between SH‐POSS and UVSE than physical blending. Moreover, the steric effect of branched and rigid SH‐POSS restricted the movement of UVSE molecular chains. Incorporating SH‐POSS also suppressed UVSE degradation and improved its thermal stability. Additionally, when the LED sample encapsulated by SH‐POSS/UVSE‐30 was immersed in boiling red ink for 2 h, no crack or stain was observed, indicating that SH‐POSS/UVSE‐30 possessed good adhesion to the LED lead frame. This work provides a new approach to fabricating high‐strength and stable silicone composites, which are promising candidates as LED encapsulants.

Arc-shaped air layer bioinspired by ginkgo nut to resist high humidity environment for PET fabrics

Developing simple processes and significant effect modification method for polyester (PET) fabrics to resist hygrothermal aging is a formidable challenge. In this study, inspired by the silver mirror phenomenon of natural ginkgo nut, we utilized the pea pod-shaped nanoparticles that zinc oxide (ZnO) was encapsulated in polyhedral oligomeric silsesquioxane (ZnO@POSS), and polydimethylsiloxane (PDMS) to construct stabilized arc-shaped air layer on the PET fabric surface to resist high humidity environment. The round belly structures of pea pod-shaped ZnO@POSS and interlaced physical networks assisted by PDMS on the PET fabrics surface served as the crucial roles to capture and retain air, resulting in the capacity of the arc-shaped air layer was significantly larger than other microstructures underwater. The water vapor was prevented from entering the fabric interstices that the self-catalytic hydrolysis behavior of PET macromolecular chains was efficiently restrained, and the strength retention of PET fabric was significantly improved from 45 % to 89 % after accelerated hygrothermal aging test (60 °C, 80 % RH, 600 h). This work represents a simple and effective approach to improve the durability for PET fabrics in high humidity environments.

Surface amphiphilic hybrid porous polymers based on cage-like organosiloxanes for pipette tip solid-phase extraction of microcystins in water

The occurrence of microcystins (MCs) during harmful algal blooms (HABs) represents a major threat to freshwater environments. In this work, a novel surface amphiphilic hybrid porous polymers based on cage-like organosiloxanes (PCSs) was prepared for the enrichment of MCs. The copolymerization of bifunctional amphiphilic monomers, 2-methacryloyloxyethyl phosphorylcholine (MPC) and N-benzylquininium chloride (BQN), with the cross-linker methacryl substituted polyhedral oligomeric silsesquioxane (POSS) was achieved in an ionic liquid-based porogenic medium. The hierarchical porous structure, a variety of surface functional groups and weak hydrophilicity were well characterized on the prepared materials using scanning electron microscopy, nitrogen adsorption/desorption analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential analysis and water contact angle testing, respectively. The as-prepared surface amphiphilic PCSs was used as an adsorbent for pipette tip solid-phase extraction (PT-SPE) to enrich microcystins (MCs) from surface waters before their analysis by capillary electrochromatography (CEC) and liquid chromatography-mass spectrometry (LC-MS). Under the optimal conditions, the established PT-SPE-LC-MS method exhibited a wide linear range (10–10,000 ng L−1), low limits of detection (4.0–8.0 ng L−1) and satisfactory recoveries (89.5–102.8 %) for MCs. An adsorption mechanism involving electrostatic interactions, hydrogen bonding, hydrophilic interactions, and π-π stacking has been proposed. The findings suggest that the use of surface amphiphilic PCSs materials as adsorbents in the PT-SPE platform facilitates efficient enrichment of MCs for subsequent chromatographic analysis. These investigations offer a new perspective on the simple and uncomplicated pretreatment of complex environmental samples.

Enhancing flame retardancy in 3D printed polyamide composites using directionally arranged recycled carbon fiber

Combining recycled carbon fiber (rCF) and 3D printing technology has shown great potential for fabricating functional prototypes and production parts used in the aerospace and automotive industries. However, it is still a challenge to design flame-retardant 3D printed parts with high mechanical properties and flame-retardant rating. In the work, a flame-retardant polyamide (PA)-based composite for material extrusion 3D printing was prepared by utilization of rCF, polyhedral oligomeric silsesquioxanes (POSS), and 9,10-Dihydro-9-oxa-10-phosphaphenanthrene (DOPO)-based flame retardant. The 3D-printed composites have high thermal stability, mechanical properties, and excellent flame retardancy with a V-0 rating. With the benefits of material extrusion 3D printing, directionally arranged rCF in 3D printed composites could effectively inhibit the fire spread, extend the time to ignition (TTI), reduce the total heat release (THR) and total smoke release (TSR) of 3D printed composites. The directional flame-retardant mechanism is mainly the thermal conductivity mechanism of the condensed phase and the promotion of stable ordered carbon layer formation. It provides a promising path for designing high-performance flame-retardant materials.

POSS‐reinforced covalent network in epoxy adhesive and its improvement in the high‐temperature adhesion, toughness, and transparency

AbstractDeveloping epoxy structural adhesives with excellent high‐temperature adhesion remains a great challenge. The incorporation of fillers can enhance the performance of epoxy adhesives, albeit at the expense of reduced high‐temperature adhesion properties. Polyhedral oligomeric silsesquioxanes (POSS) is considered a promising filler for enhancing high‐temperature adhesion properties due to its excellent compatibility and nano cage‐structured. Herein, the rigid cage‐structured was covalently introduced epoxy adhesives to improve the high‐temperature adhesion properties. The introduction of 1 wt% POSS significantly increased the high‐temperature (120°C) adhesion strength by 197% and toughness by 283%. The POSS‐reinforced adhesive also featured excellent wide temperature adaptability, indicating that it maintained high adhesion strength at various temperatures. Furthermore, POSS drastically enhanced the transparency of epoxy adhesive by three times. It is highly anticipated that this work will open a new avenue of designing epoxy adhesives with the excellent high‐temperature adhesion properties and transparency.

Synthesis of carboxyl group functionalized polyhedral oligomeric silsesquioxane for fabricating ultrastable foams driven by high temperature and salinity

Aqueous foams are thermodynamically unstable systems, and their instability increases with temperature and salinity. In this study, we successfully synthesized an amphiphilic polyhedral oligomeric silsesquioxane, POSS-NH2-BTCA, featuring phenyl and carboxyl groups, through a substitution reaction. Highly stable foams were prepared under temperatures conditions ranging from 50 to 90 °C and salinity levels between 20 and 80 g/L. Rheological tests and scanning electron microscopy analysis show that the interactions between divalent ions and carboxyl groups improve the film strength. However, the half-life of the drainage only increased from 38 s to 55 s. Therefore, the enhancement in foam stability is believed to be caused by the inhibition of coarsening and coalescence rather than the suppression of drainage. The strategy for fabricating amphiphilic nanoparticles can serve as a reference for designing new foam stabilizers for high temperature and salinity conditions.

Sulfonating and polyhedral oligomeric silsesquioxane crosslinking in one step to build multiple proton pathways for proton exchange membrane fuel cells over a wide temperature range

Developing proton exchange membrane fuel cells (PEMFCs) operating over a wide temperature range can avoid additional internal/external heating or cooling devices for the PEMFCs operating. Polybenzimidazole (PBI) doped with phosphoric acid (PA) exhibits significant potential in high-temperature proton exchange membrane fuel cells (HT-PEMFCs). Nevertheless, the traditional PA-PBI membranes are limited to operating within 140∼180 °C. In this work, a sulfonated polyhedral oligomeric silsesquioxane crosslinked polybenzimidazole membrane enriched pyridine and diazafluorene (CSPBI-X) is prepared where the sulfonation and crosslinking are accomplished by one-step heating. The theoretical calculations confirm that PA molecules have strong interactions with sulfonic acid groups and nitrogen-containing groups, enabling the membrane to achieve proton conductivity in a wide temperature range (80–180 °C). Moreover, the cross-linked sulfonated membranes have excellent PA retention ratio as high as 83.8% under 80 °C and 40% relative humidity for 120 h. Remarkably, with the acid doping level of 7.6, the proton conductivity of the CSPBI-20 membrane reaches 0.0491 S cm−1 and 0.145 S cm−1 at 80 °C and 180 °C in dry state, respectively. The highest power density of the CSPBI-20 at 80, 100, 120, 140, 160, and 180 °C is 257.3, 362.9, 485.3, 604.6, 755.3, and 956.1 mW cm−2, respectively.