다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Polydopamine and Its Derivative Materials: Synthesis and Promising Applications in Energy, Environmental, and Biomedical Fields

Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

5. In Situ Polymerization 3907 5.1. General Polymerization 3907 5.2. Photopolymerization 3910 5.3. Surface-Initiated Polymerization 3912 5.4. Other Methods 3913 6. Colloidal Nanocomposites 3913 6.1. Sol-Gel Process 3914 6.2. In Situ Polymerization 3916 6.2.1. Emulsion Polymerization 3917 6.2.2. Emulsifier-Free Emulsion Polymerization 3919 6.2.3. Miniemulsion Polymerization 3920 6.2.4. Dispersion Polymerization 3921 6.2.5. Other Polymerization Methods 3923 6.2.6. Conducting Nanocomposites 3924 6.3. Self Assembly 3926 7. Other Preparative Methods 3926 8. Characterization and Properties 3928 8.1. Chemical Structure 3928 8.2. Microstructure and Morphology 3929 8.3. Mechanical Properties 3933 8.3.1. Tensile, Impact, and Flexural Properties 3933 8.3.2. Hardness 3936 8.3.3. Fracture Toughness 3937 8.3.4. Friction and Wear Properties 3937 8.4. Thermal Properties 3938 8.5. Flame-Retardant Properties 3941 8.6. Optical Properties 3942 8.7. Gas Transport Properties 3943 8.8. Rheological Properties 3945 8.9. Electrical Properties 3945 8.10. Other Characterization Techniques 3946 9. Applications 3947 9.1. Coatings 3947 9.2. Proton Exchange Membranes 3948 9.3. Pervaporation Membranes 3948 9.4. Encapsulation of Organic Light-Emitting Devices 3948

Polymer/Silica Nanocomposites: Preparation, Characterization, Properties, and Applications

Surface modification of inorganic nanoparticles for development of organic–inorganic nanocomposites—A review

Covalent organic frameworks (COFs) hold great promise in molecular separations owing to their robust, ordered and tunable porous network structures. Currently, the pore size of COFs is usually much larger than most small molecules. Meanwhile, the weak interlamellar interaction between COF nanosheets impedes the preparation of defect-free membranes. Herein, we report a series of COF membranes through a mixed-dimensional assembly of 2D COF nanosheets and 1D cellulose nanofibers (CNFs). The pore size of 0.45–1.0 nm is acquired from the sheltering effect of CNFs, rendering membranes precise molecular sieving ability, besides the multiple interactions between COFs and CNFs elevate membrane stability. Accordingly, the membranes exhibit a flux of 8.53 kg m−2 h−1 with a separation factor of 3876 for n-butanol dehydration, and high permeance of 42.8 L m−2 h−1 bar−1 with a rejection of 96.8% for Na2SO4 removal. Our mixed-dimensional design may inspire the fabrication and application of COF membranes. The fabrication of defect-free covalent organic framework (COF) membranes for the separation of small molecules is challenging. Here, the authors report robust COF membranes with precise molecular sieving through a mixed-dimensional assembly, exhibiting high performance for alcohol dehydration and salt rejection.

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Covalent organic framework membranes through a mixed-dimensional assembly for molecular separations.

Composite membranes comprising a continuous polymer phase and a dispersed filler phase have revealed appealing potential in selective transport of molecules and ions. The multiphase characteristics of composite membranes provide more degrees of freedom to manipulate multiple interactions, tailor multiscale structures, and integrate multiple functionalities, compared to pristine polymer membranes. In this feature article, we have reviewed the various methods for the fabrication of composite membranes. In particular, we have thoroughly discussed two typical methods: the physical blending method and the sol–gel method. For each method, the major advances and challenges have been summarized. We have also tentatively delineated the new generation of composite membranes.

Recent advances in the fabrication of advanced composite membranes

Metal-organic framework (MOF) glasses are promising candidates for membrane fabrication due to their significant porosity, the ease of processing, and most notably, the potential to eliminate the grain boundary that is unavoidable for polycrystalline MOF membranes. Herein, we developed a ZIF-62 MOF glass membrane and exploited its intrinsic gas-separation properties. The MOF glass membrane was fabricated by melt-quenching treatment of an in situ solvothermally synthesized polycrystalline ZIF-62 MOF membrane on a porous ceramic alumina support. The molten ZIF-62 phase penetrated into the nanopores of the support and eliminated the formation of intercrystalline defects in the resultant glass membrane. The molecular sieving ability of the MOF membrane is remarkably enhanced via vitrification. The separation factors of the MOF glass membrane for H2 /CH4 , CO2 /N2 and CO2 /CH4 mixtures are 50.7, 34.5, and 36.6, respectively, far exceeding the Robeson upper bounds.

A MOF Glass Membrane for Gas Separation

Enhanced water permeation through sodium alginate membranes by incorporating graphene oxides

In nature, the biological membrane can selectively transport essential small molecules/ions through facilitated diffusion via carrier proteins. Intrigued by this phenomenon and principle, membrane researchers have successfully employed synthetic carriers and carrier-mediated reversible reactions to enhance the separation performance of synthetic membranes. However, the existing facilitated transport membranes as well as the relevant facilitated transport theories have scarcely been comprehensively reviewed in the literature. This tutorial review primarily covers the two aspects of facilitated transport theories: carrier-mediated transport mechanisms and facilitated transport chemistries, including the design and fabrication of facilitated transport membranes. The applications of facilitated transport membranes in energy-intensive membrane processes (gas separation, pervaporation, and proton exchange membrane fuel cells) have also been discussed. Hopefully, this review will provide guidelines for the future research and development of facilitated transport membranes with high energy efficiency.

Fusheng Pan

Papers

Covalent organic framework membranes through a mixed-dimensional assembly for molecular separations.

Recent advances in the fabrication of advanced composite membranes

A MOF Glass Membrane for Gas Separation

Enhanced water permeation through sodium alginate membranes by incorporating graphene oxides

Facilitated transport of small molecules and ions for energy-efficient membranes