We have studied the morphology of blends of PS/PMMA, PC/SAN24, and PMMA/EVA and compared the morphologies with and without modified organoclay Cloisite 20A or Cloisite 6A clays. In each case we found a large reduction in domains size and the localization of the clay platelets along the interfaces of the components. The increased miscibility was accompanied in some cases, with the reduction of the system from multiple values of the glass transition temperatures to one. In addition, the modulus of all the systems increased significantly. A model was proposed where it was proposed that in-situ grafts were forming on the clay surfaces during blending and the grafts then had to be localized at the interfaces. This blending mechanism reflects the composition of the blend and is fairly nonspecific. As a result, this may be a promising technology for use in processing recycled blends where the composition is often uncertain and price is of general concern.

Morphology, thermal and rheological properties of polymer-organoclay composites prepared by melt-blending of polystyrene (PS), poly(methyl methacrylate) (PMMA), and PS/PMMA blends with Cloisite organoclays were examined by transmission electron microscopy, small-angle X-ray scattering, secondary ion mass spectroscopy, differential scanning calorimetry, and rheological techniques. Organoclay particles were finely dispersed and predominantly delaminated in PMMA-clay composites, whereas organoclays formed micrometer-sized aggregates in PS-clay composites. In PS/PMMA blends, the majority of clay particles was concentrated in the PMMA phase and in the interfacial region between PS and PMMA. Although incompatible PS/PMMA blends remained phaseseparated after being melt-blended with organoclays, the addition of organoclays resulted in a drastic reduction in the average microdomain sizes (from 1-1.5 m to ca. 300 -500 nm), indicating that organoclays partially compatibilized the immiscible PS/PMMA blends. The effect of surfactant (di-methyl di-octadecyl-ammonia chloride), used in the preparation of organoclays, on the PS/PMMA miscibility was also investigated. The free surfactant was more compatible with PMMA than with PS; the surfactant was concentrated in PMMA and in the interfacial region of the blends. The microdomain size reduction resulting from the addition of organoclays was definitely more significant than that caused by adding the same amount of free surfactant without clay. The effect of organoclays on the rheological properties was insignificant in all tested systems, suggesting weak interactions between the clay particles and the polymer matrix. In the PS system, PMMA, and organoclay the extent of clay exfoliation and the resultant properties are controlled by the compatibility between the polymer matrix and the surfactant rather than by interactions between the polymer and the clay surface.

HEVs (PHEVs), besides the traditional applications in portable devices. To build the next generation LIBs with higher performances, high energy density materials are urgently pursued worldwide. [1][2][3] Lithium-rich (Li-rich) materials, with the specific capacity over 260 mAh g −1 and energy density up to ≈1000 Wh kg −1 , [4] have attracted great interest in the past decades. It is reported that Li-rich materials are composed of two phases of Li 2 MnO 3 (C 2/m ) and LiMO 2 (R m 3 ) (M = Ni, Co, Mn, etc.). [5][6][7][8][9] Despite the above advantages, several concerns including structural instability and the resulted voltage degradation, as well as the poor diffusion kinetics at the interface have become the bottlenecks of Li-rich materials. [9][10][11][12][13] In this regard, multifarious modification approaches, such as doping and surface coating, have been intensively investigated. [14][15][16] Particularly, Li + diffusion at the cathode-electrolyte interphase (CEI) is widely regarded as the rate determining step in LIBs. [17][18][19] From this viewpoint, metal fluorides (FeF 3 , [20] MOF, [21,22] AlF 3 , [23,24] etc.), metal oxides (MgO, [25] Al 2 O 3 , [26,27] etc.), metal phosphates (AlPO 4 , [28] LaPO 4 , [29] Li 3 PO 4 , [30] FePO 4 /Li 3 PO 4 , [31] Li-Mn-PO 4 , [32] etc.), and those with similar structure of Li-rich Li 2 MnO 3 (Li 2 SiO 3 [33,34] and Li 2 SnO 3 , [35] ) have been widely applied to modify the surface of bulk Li-rich materials. Recently, fast lithium-ion conductors (LiVO 3 , [36] Li 2 ZrO 3 , [37] Li-La-Ti-O, [38,39] LiPON, [40] etc.) have also been proposed to decorate the surface of Li-rich cathodes to enhance the apparent diffusion coefficients. All the aforesaid surface modification materials, unexceptionally, have been proved to be effective in both stabilizing the structure and facilitating the Li + kinetics. Nevertheless, in general, the decoration layers themselves seem rather "passive" in promoting Li + diffusion. Assuming they are Li + conductive (e.g., solid electrolyte materials), fast Li + diffusion channels will be provided besides the general separation effect (in suppressing side reactions and inevitable TM dissolution). As for Li + insulators (e.g., metal fluorides), only the benefit of physical barriers could be exploited. Therefore, a more "initiative" function interface is imperative to be built to more effectively promote the Li + transport at the electrode-electrolyte interphase.It is noteworthy that piezoelectric material, as an important category in the energy-conversion community, works on the As one of the most promising cathodes for next-generation lithium ion batteries (LIBs), Li-rich materials have been extensively investigated for their high energy densities. However, the practical application of Li-rich cathodes is extremely retarded by the sluggish electrode-electrolyte interface kinetics and structure instability. In this context, piezoelectric LiTaO 3 is employed to functionalize the surface of Li 1.2 Ni 0.17 Mn 0.56 Co 0.07 O 2 (LNMCO), aiming to boost t...

Biogenesis and tissue development are based on the heterogenesis of multipotent stem cells. However, the underlying mechanisms of stem cell fate specification are unclear. Chirality is one of the most crucial factors that affects stem cell development and is implicated in asymmetrical cell morphology formation; however, its function in heterogeneous cell fate determination remains elusive. In this study, it is reported that the chirality of a constructed 3D extracellular matrix (ECM) differentiates mesenchymal stem cells to diverse lineages of osteogenic and adipogenic cells by providing primary heterogeneity. Molecular analysis shows that left‐handed chirality of the ECM enhances the clustering of the mechanosensor Itgα5, while right‐handed chirality decreases this effect. These differential adhesion patterns further activate distinct mechanotransduction events involving the contractile state, focal adhesion kinase/extracellular signal‐regulated kinase 1/2 cascades, and yes‐associated protein/runt‐related transcription factor 2 nuclear translocation, which direct heterogeneous differentiation. Moreover, theoretical modeling demonstrates that diverse chirality mechanosensing is initiated by biphasic modes of fibronectin tethering. The findings of chirality‐dependent lineage specification of stem cells provide potential strategies for the biogenesis of organisms and regenerative therapies.

Bacterial infection is the main cause of implantation failure worldwide, and the importance of antibiotics on medical devices has been undermined because of antibiotic resistance. Antimicrobial hydrogels have emerged as a promising approach to combat infections associated with medical devices and wound healing. However, hydrogel coatings that simultaneously possess both antifouling and antimicrobial attributes are scarce. Herein, we report an antimicrobial hydrogel that incorporates adhesion-inhibiting polyethylene glycol (PEG) and colony-suppressing chitosan (CS) as a dressing to combat bacterial infections. These two polymers have important environmentally benign characteristics including low toxicity, low volatility, and biocompatibility. Although hydrogels containing PEG and CS have been reported for applications in the fields of wound dressing, tissue repair, water purification, drug delivery, and scaffolds for bone regeneration, there still has been no report on the application of CS/PEG hydrogel coatings in dental applications. Herein, this biointerface shows superior activity in early-stage adhesion inhibition (98.8%, 5 h) and displays remarkably long-lasting colony-suppression activity (93.3%, 7 d). Thus, this novel nanomaterial, which has potential as a dual-functional platform with integrated antifouling and antimicrobial functions with excellent biocompatibility, might be used as a safe and effective antimicrobial coating in biomedical device applications.

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The current density j s and relaxation rate Q have been measured on a ring shaped Tl 2 Ba 2 CaCu 2 O 8 film between 4.2 K and the irreversibility temperature in magnetic fields up to 7 T. The temperature and field dependent exponent m͑T , B e ͒ used to parametrize the activation energy U in the form U͑ j s , T , B e ͒ ͑U c ͞m͒ ͓͑ j c ͞j s ͒ m 2 1͔ is determined for many different fields. In the B e -T phase diagram we associate the m 0 line with the glass temperature T g and find that T g essentially drops to 0 K at B e ഠ 0.7 T, which indicates a dimensional crossover at this field. The m . 0 region ͑B e , 0.7 T, T # 55 K͒ corresponds to 3D elastic vortex motin while the m , 0 region corresponds to 2D dislocation mediated flux creep. [S0031-9007(97) The small coherence length, the presence of weak and dense point pinning centers, and the layered structure of high-T c superconductors are at the origin of the intricate nature of the mixed state phase diagram of these superconductors [1][2][3][4]. A lot of effort has been put into investigations of various phases and phase transitions [5][6][7][8]. It is generally believed that below the irreversibility line B irr ͑T ͒ there exists a vortex solid state which is usually described in terms of collective flux pinning (CFP) [3,4] or vortex glass (VG) [2,9] models. Both the CFP and VG models are based on elastic vortex motion. Dissipation due to the thermally activated motion of vortices is associated with an electric field E y 0 B e exp͓2U͑ j s , T , B e ͒͞k B T ͔, where U͑ j s , T, B e ͒ ͑U c ͞m͒ ͓͑ j c ͞j s ͒ m 2 1͔ is the activation energy at the external magnetic field B e and temperature T, y 0 an attempt hopping velocity, and U c the characteristic pinning energy. The superconducting current density j s is always smaller than the critical current j c for which U vanishes. Many different values have been predicted theoretically for the parameter m on the basis of the CFP and VG models. For all regimes and dimensionalities [1-4,9], however, it is found that m $ 0. A direct conclusion then is that the activation energy diverges when the current j s approaches 0. This is reasonable for a 3D elastic vortex system, but for a 2D vortex system, it may not be true [9]. For example, for a 2D system, the vortex glass state does not exist at finite temperatures [1,10]. As mentioned by Vinokur et al. [4], in strongly layered systems such as Bi 2 Sr 2 CaCu 2 O 8 and Tl 2 Ba 2 CaCu 2 O 8 pinning is too strong at high magnetic fields to allow vortices to creep collectively. Instead, dislocation-mediated (plastic) creep is expected to be predominant. However, as far as we know, no direct evidence has been found for plastic creep except in a small part of the phase diagram ͑T . 81 K and B e , 6 T͒ of a YBa 2 Cu 3 O 7 single crystal with a fishtail effect [11]. In this Letter, we conclude from a detailed investigation of the vortex dynamics in high quality Tl 2 Ba 2 CaCu 2 O 8 thin films that the B e -T plane below the irreversibility line is separated into two regions by a m 0 lin...

Bioinspired nanochannels for smart mass transport control have shown great potential for various applications in nanofluids, biosensing, and separation. Here, a nanochannel-based smart responsive platform exhibiting high formaldehyde (HCHO) sensitivity is designed and successfully fabricated by functionalizing the inner pore surface with ethylenediamine (EDA). By employing the nucleophilic addition reaction between HCHO and EDA immobilized on the nanochannels, the artificial nanochannels can switch from an open state to a closed state with the increase in HCHO. This is because the surface charge density and the wettability of the nanochannels change along with the HCHO immobilization. Meanwhile, the EDA-functionalized platform can hold a large amount of HCHO due to the abundant nanochannels of the membrane, so it presents a significant ability to remove HCHO in complex matrices. Also, the cultivation of mesenchymal stem cells in media containing HCHO can achieve excellent vitality in the presence of the EDA-functionalized nanochannels materials. This work paves an avenue for designing and developing bioinspired nanochannel based platform for harmful compounds detection and removal.