Tuning the Cell Adhesion on Biofunctionalized Nanoporous Organic Frameworks

The ability to control the structure and surface chemistry of biomaterials on a molecular level is crucial for optimizing their performance. Here, a novel type of nanoporous organic framework that is suited for the fabrication of thin films is described. These surface‐grafted gels (SURGELs) are prepared and functionalized using two orthogonal, metal‐free click chemistries. The SURGELs are shown to be cytocompatible and to efficiently mediate adhesion of osteoblast‐like cells. This process can be further enhanced by surface modification. In addition, the use of light‐triggered reactions in combination with photomasks allows a patterned functionalization of the substrates. The potential to vary and exactly adjust the parameters within the SURGEL polymer network (including porosity and exact network topology on the nanometer scale as well as addressable functional groups) combined with the ability to functionalize their surfaces with any clickable biomolecule of choice in any desired pattern allow the targeted design of novel SURGEL‐based biomaterials for applications in nanomedicine, tissue engineering scaffolds, wound dressing,and medical implants.     

A study of the effect of post-metal etch wet cleaning processes and silicon oxynitride film on charge induced corrosion of tungsten vias

We report the experimental study of prevention of charge induced corrosion of tungsten vias after metal etch using wet chemical solutions and silicon oxynitride (SiON) shielding film. It was found that one of the solutions could effectively prevent corrosion of tungsten vias and leave essentially no polymer residue on metal lines. The performance of other solutions is poor due to the formation of polymer residues or sidewall erosion on metal lines. We have demonstrated that the combination of wet chemical treatment with SiON as the dielectric charge shielding film was as effective as other standard methods for preventing corrosion of tungsten vias. It was also found that SiON has strong impacts on chamber wall conditions and metal line profile.     

纳秒激光诱导氧化钛片及涂层的润湿性研究

采用纳秒激光在纯钛片表面制备微织构,并辅助化学处理的方法,获得了类似"荷叶效应"且润湿稳定的超疏水表面。通过调整激光加工工艺参数,获得了具有不同润湿性的微纳米结构;在此基础上,采用全氟癸基三甲氧基硅烷和乙醇溶液的混合溶液在微结构表面制备涂层。采用扫描电子显微镜和能谱分析后可知钛板在激光作用下产生了多尺度的氧化钛多孔微结构;通过接触角测量表征进一步分析了钛片表面的亲水性与微纳米结构表面变化规律的关系,以及涂层对表面润湿性的影响,为生物医学药物输送方面的研究提供了参考。     

Highly Conductive Transition Metal Carbide/Carbonitride(MXene)@polystyrene Nanocomposites Fabricated by Electrostatic Assembly for Highly Efficient Electromagnetic Interference Shielding

Highly conductive polymer nanocomposites are greatly desired for electromagnetic interference (EMI) shielding applications. Although transition metal carbide/carbonitride (MXene) has shown its huge potential for producing highly conductive films and bulk materials, it still remains a great challenge to fabricate extremely conductive polymer nanocomposites with outstanding EMI shielding performance at minimal amounts of MXenes. Herein, an electrostatic assembly approach for fabricating highly conductive MXene@polystyrene nanocomposites by electrostatic assembling of negative MXene nanosheets on positive polystyrene microspheres is demonstrated, followed by compression molding. Thanks to the high conductivity of MXenes and their highly efficient conducting network within polystyrene matrix, the resultant nanocomposites exhibit not only a low percolation threshold of 0.26 vol% but also a superb conductivity of 1081 S m^?1 and an outstanding EMI shielding performance of >54 dB over the whole X‐band with a maximum of 62 dB at the low MXene loading of 1.90 vol%, which are among the best performances for electrically conductive polymer nanocomposites by far. Moreover, the same nanocomposite has a highly enhanced storage modulus, 54% and 56% higher than those of neat polystyrene and conventional MXene@polystyrene nanocomposite, respectively. This work provides a novel methodology to produce highly conductive polymer nanocomposites for highly efficient EMI shielding applications.     

Use of thin film of a Co<Subscript>15</Subscript>Ti<Subscript>40</Subscript>N<Subscript>35</Subscript> alloy for CVD catalytic growth of carbon nanotubes

It is shown that multiwalled carbon nanotubes can be grown on the catalytic surface of a Co–Ti–N alloy with low (~10 at %) cobalt content by the conventional method of chemical deposition from acetylene. Adding nitrogen to the composition of the Co–Ti contributes the formation of the TiN compound and extrusion of Co onto the surface where it makes a catalytic effect for CNT growth. It was found that the tubes begin growth at a temperature of 400°C. It is shown by studies using Raman spectroscopy that the quality of CNT improves with increasing temperature.     

Crystallization of 2D Hybrid Organic–Inorganic Perovskites Templated by Conductive Substrates

2D hybrid organic–inorganic perovskites are valued in optoelectronic applications for their tunable bandgap and excellent moisture and irradiation stability. These properties stem from both the chemical composition and crystallinity of the layer formed. Defects in the lattice, impurities, and crystal grain boundaries generally introduce trap states and surface energy pinning, limiting the ultimate performance of the perovskite; hence, an in-depth understanding of the crystallization process is indispensable. Here, a kinetic and thermodynamic study of 2D perovskite layer crystallization on transparent conductive substrates are provided—fluorine-doped tin oxide and graphene. Due to markedly different surface structure and chemistry, the two substrates interact differently with the perovskite layer. A time-resolved grazing-incidence wide-angle X-ray scattering (GIWAXS) is used to monitor the crystallization on the two substrates. Molecular dynamics simulations are employed to explain the experimental data and to rationalize the perovskite layer formation. The findings assist substrate selection based on the required film morphology, revealing the structural dynamics during the crystallization process, thus helping to tackle the technological challenges of structure formation of 2D perovskites for optoelectronic devices.     

Chemically Homogeneous Complex Oxide Thin Films Via Improved Substrate Metallization

A long‐standing challenge to the widespread application of complex oxide thin films is the stable and robust integration of noble metal electrodes, such as platinum, which remains the optimal choice for numerous applications. By considering both work of adhesion and stability against chemical diffusion, it is demonstrated that the use of an improved adhesion layer (namely, ZnO) between the silicon substrate and platinum bottom electrode enables dramatic improvements in the properties of the overlying functional oxide films. Using BaTiO₃ and Pb(Zr,Ti)O₃ films as test cases, it is shown that the use of ZnO as the adhesion layer leads directly to increased process temperature capabilities and dramatic improvements in chemical homogeneity of the films. These result in significant property enhancements (e.g., 300% improvement to bulk‐like permittivity for the BaTiO₃ films) of oxide films prepared on Pt/ZnO as compared to the conventional Pt/Ti and Pt/TiO_x stacks. A comparison of electrical, structural, and chemical properties that demonstrate the impact of adhesion layer chemistry on the chemical homogeneity of the overlying complex oxide is presented. Collectively, this analysis shows that in addition to the simple need for adhesion, metal‐oxide layers between noble metals and silicon can have tremendous chemical impact on the terminal complex oxide layers.     

Graphene Oxide-Assisted Multiple Cross-Linking of MXene for Large-Area,High-Strength,Oxidation-Resistant,and Multifunctional Films

Transition metal carbides/nitrides (MXenes) with metallic electrical conductivity and excellent processability attract increasing attention for assembling multifunctional macrostructures. However, the challenges, involving poor mechanical strength, inferior oxidation stability, and limited scalable manufacturing, impede their wide applications. Herein, the large-area, high-strength, ultra-flexible hybrid films are developed through the multiple physical and chemical cross-linking of MXene/cellulose films facilitated by graphene oxide. The MXene-based films manifest significantly improved hydrophobicity, water/solvent resistance, and oxidation stability, and meanwhile, maintain excellent conductivity and electromagnetic interference shielding performance. The X-band surface-specific shielding effectiveness (SE) of 18,837.5 dB cm² g⁻¹ and an SE over 60 dB in an ultra-broadband frequency range are achieved, comparable to the best shields ever reported. Furthermore, the wearable films demonstrate excellent photothermal antibacterial and electrothermal deicing applications. Thus, such high-performance MXene-based films developed through a facile and scalable manufacturing method have substantial application prospects in flexible electronics, thermotherapy, electromagnetic compatibility, and aerospace.     

Plant‐Inspired Pyrogallol‐Containing Functional Materials

Pyrogallol‐containing molecules are ubiquitous in the plant kingdom. The chemical synthesis of these molecules remains challenging. Thus, they are obtained via purification from heterogeneous mixtures of plant extracts. Previous studies have focused on their biological roles, such as antioxidants. Additionally, the molecules are used as ink colorants and in tanning processes for leather. Recently, many disciplines have paid attention to adhesiveness of pyrogallol‐containing molecules, including the control of interface properties in energy storage/generation and medical devices, as well as the changes in wettability related to membrane technologies. In particular, pyrogallol‐containing molecules act as “molecular glues,” binding to virtually all biomacromolecules, for example, DNA/RNA, soluble proteins, insoluble extracellular matrices, and peptides. Furthermore, the cohesion of pyrogallol by forming pyrogallol‐to‐pyrogallol covalent bonds is useful for the preparation of bulk hydrogels and thin films. The content of this review focuses on interactions with biomacromolecules used as molecular glues, used as modifiers in material‐independent surface chemistry, and applied as chemical moieties to form covalent linkages to fabricate hydrogels and related biomaterials. Future perspectives include the development of new pyrogallol‐containing materials, the understanding of chirality in adhesion, and the improvement of the mechanical stability for applications in various biomedical, energy, and industrial devices.     

High Throughput Screening of Dynamic Silk‐Elastin‐Like Protein Biomaterials

The need for dynamic, elastomeric polymeric biomaterials remains high, with few options with tunable control of mechanical properties, and environmental responses. Yet the diversity of these types of protein polymers pursued for biomaterials‐related needs remains limited. Robust high‐throughput synthesis and characterization methods will address the need to expand options for protein‐polymers for a range of applications. Here, a combinatorial library approach with high throughput screening is used to select specific examples of dynamic protein silk‐elastin‐like polypeptides (SELPs) with unique stimuli responsive features, including tensile strength and adhesion. Using this approach, 64 different SELPs with different sequences and molecular weights are selected out of over 2000 recombinant E. coli colonies. New understanding of sequence‐function relationships with this family of proteins is gained through this combinatorial‐screening approach and can provide a guide to future library designs. Further, this approach yields new families of SELPs to match specific material functions.     

多层陶瓷电容器BaNd_2Ti_4O_(12)的化学腐蚀研究

以混合酸作为腐蚀液,研究了BaNd2Ti4O12多层陶瓷电容器的化学腐蚀的工艺条件。提高酸的浓度、时间和温度,都会加快腐蚀,其中温度的影响最大。硝酸替代氢氟酸,无法将BaNd2Ti4O12样品的晶界腐蚀出来。适宜的腐蚀条件为:40%氢氟酸3 mL、浓盐酸12 mL配制成100 mL溶液,加热温度60℃,时间30 s。     

Preparation of Metallic Films on Elastomeric Stamps and Their Application for Contact Processing and Contact Printing

The formation of permanent or reversible metallic patterns on a substrate has applications in microfabrication and analytical techniques. Here, we investigate how to metallize an elastomeric stamp, either for processing of a substrate mediated by the proximity between the metal on the stamp and an active layer on the substrate, or for contact printing of the metal from a stamp to a substrate. The stamps were made from poly(dimethylsiloxane) (PDMS) and were modified before metallizing them with Au by adding to or removing from their bulk mobile silicone residues, by oxidizing their surface with an O₂‐plasma, by surface‐fluorination via silanization, or by priming them with a Ti layer. The interplay between the adhesion of the different layers defines two categories of application: contact processing and contact printing. Contact processing corresponds to keeping the metal on the stamp after contacting a substrate; it is reversible and nondestructive, and useful to define transient electrical contacts or quench fluorescence on a surface, for example. Contact printing occurs when the metal on the stamp adheres to the printed surface. Contact printing can transfer a metal, layers of metals, or an oxide onto a substrate with submicrometer lateral resolution. The transfer can be total or localized to the regions of contact, depending on the morphology of the metal on the stamp and/or the surface chemistry of the substrate.     

生物医用钛合金的激光表面改性

生物医用钛及其合金是外科植入首选的替代材料，激光表面改性是改善钛合金表面磨损和腐蚀性能的有效方法。采用高功率连续波Nd:YAG激光在Ti6Al4V合金表面进行激光气体氮化改性，获得了均匀致密、无孔洞裂纹等缺陷的氮化物改性层，合金表面对人体有害元素Al、V含量明显降低。利用扫描电子显微镜(SEM)、显微硬度计、振动摩擦磨损实验机及恒电位仪对Ti6Al4V合金气体氮化改性层的组织、磨损及在模拟人体体液中的电化学腐蚀性能进行研究。实验结果表明，激光气体氮化改善了Ti6Al4V合金作为生物医学材料使用的表面性能，其抗磨损及腐蚀性能显著提高。     

Multifunctional and Water‐Resistant MXene‐Decorated Polyester Textiles with Outstanding Electromagnetic Interference Shielding and Joule Heating Performances

Although multifunctional, flexible, and wearable textiles with integrated smart electronics have attracted tremendous attention in recent years, it is still an issue to balance new functionalities with the inherent performances of the textile substrates. 2D early transition metal carbides/nitrides (MXenes) are considered as ideal nanosheets for fabricating multifunctional and flexible textiles on the basis of their superb intrinsic electrical conductivity, tunable surface chemistry, and layered structure. Herein, highly conductive and hydrophobic textiles with exceptional electromagnetic interference (EMI) shielding efficiency and excellent Joule heating performance are fabricated by depositing in situ polymerized polypyrrole (PPy) modified MXene sheets onto poly(ethylene terephthalate) textiles followed by a silicone coating. The resultant multifunctional textile exhibits high electrical conductivity of ≈1000 S m^?1 in conjunction with an exceptional EMI shielding efficiency of ≈90 dB at a thickness of 1.3 mm. The thin silicone coating renders the hydrophilic PPy/MXene‐decorated textile hydrophobic, leading to an excellent water‐resistant feature while retaining a satisfactory air permeability of the textile. Interestingly, the multifunctional textile also exhibits an excellent moderate voltage‐driven Joule heating performance. Thus, the deposition of PPy‐modified MXene followed by silicone coating creates a multifunctional textile that holds great promise for wearable intelligent garments, EMI shielding, and personal heating applications.     

Polysulfide Filter and Dendrite Inhibitor: Highly Graphitized Wood Framework Inhibits Polysulfide Shuttle and Lithium Dendrites in Li–S Batteries

The design and manufacture of advanced materials based on biomaterials provide new opportunities to solve many technological challenges. In this work, a highly graphitized wood framework (GWF) with a porous tunnel structure and microvilli is constructed as a multifunctional interlayer to improve the electrochemical performance of lithium–sulfur (Li–S) batteries. The GWF not only retains the 3D transport network of wood, but also offers increased deposition sites for polysulfides through the microvilli which grow on the inner surfaces of the carbon tunnels. Electrochemical tests show that GWF effectively enhances the initial discharge capacity of the Li–S battery to 1593 mAh g⁻¹ at 0.05 C, with a low capacity decline of 0.06% per cycle at 1 C. Besides, the GWF interlayer also effectively protects lithium anodes from corrosion by S_x²⁻, thus they still keep their metallic luster and clean surface even after long charge-discharge cycles. These enhancements are attributed to the high conductivity, abundant microvilli, and tunnel confinement effects of GWF, which effectively inhibit the shuttle effect of polysulfides by the same principle as nose hairs filtering the air. This work presents a new understanding of bionic/biomaterials and a new strategy to improve the performance of Li–S batteries.     

Real-time stress evolution during Si1-xGex Heteroepitaxy: Dislocations, islanding, and segregation

We have used sensitive real-time measurements of film stress during Si_1-xGe_x molecular beam epitaxy to examine strain relaxation due to coherent island formation, and to probe the kinetics of Ge surface segregation. We first describe our novel curvature-measurement technique for real-time stress determination. Measurements of the relaxation kinetics during high temperature Si₇₉Ge₂₁ growth on Si (001) are reported in which formation of highly regular arrays of [501]-faceted islands produce 20% stress relaxation. An island shape transition is also observed that reduces the effective stress by up to 50% without dislocations. Nonuniform composition profiles due to Ge surface segregation during growth of planar alloy films are determined with submonolayer thickness resolution from the real-time stress evolution. Up to two monolayers of Ge can segregate to the growth surface.     

Interaction of Zoospores of the Green Alga Ulva with Bioinspired Micro‐ and Nanostructured Surfaces Prepared by Polyelectrolyte Layer‐by‐Layer Self‐Assembly

The interaction of spores of Ulva with bioinspired structured surfaces in the nanometer–micrometer size range is investigated using a series of coatings with systematically varying morphology and chemistry, which allows separation of the contributions of morphology and surface chemistry to settlement (attachment) and adhesion strength. Structured surfaces are prepared by layer‐by‐layer spray‐coating deposition of polyelectrolytes. By changing the pH during application of oppositely charged poly(acrylic acid) and polyethylenimine polyelectrolytes, the surface structures are systematically varied, which allows the influence of morphology on the biological response to be determined. In order to discriminate morphological from chemical effects, surfaces are chemically modified with poly(ethylene glycol) and tridecafluoroctyltriethoxysilane. This chemical modification changes the water contact angles while the influence of the morphology is retained. The lowest level of settlement is observed for structures of the order 2 µm. All surfaces are characterized with respect to their wettability, chemical composition, and morphological properties by contact angle measurement, X‐ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy.     

Surface-Bound Microgels for Separation,Sensing, and Biomedical Applications

This study presents a comprehensive survey of microgel-coated materials and their functional behavior, describing the complex interplay between the physicochemical and mechanical properties of the microgels and the chemical and morphological features of substrates. The cited literature is articulated in four main sections: i) properties of 2D and 3D substrates, ii) synthesis, modification, and characterization of the microgels, iii) deposition techniques and surface patterning, and iv) application of microgel-coated surfaces focusing on separations, sensing, and biomedical applications. Each section discusses – by way of principles and examples – how the various design parameters work in concert to deliver functionality to the composite systems. The case studies presented herein are viewed through a multi-scale lens. At the molecular level, the surface chemistry and the monomer make-up of the microgels endow responsiveness to environmental and artificial physical and chemical cues. At the micro-scale, the response effects shifts in size, mechanical, and optical properties, and affinity towards species in the surrounding liquid medium, ranging from small molecules to cells. These phenomena culminate at the macro-scale in measurable, reversible, and reproducible effects, aiming in a myriad of directions, from lab-scale to industrial applications.     

Click Chemistry in Materials Science

Despite originating only a little more than a decade ago, click chemistry has become one of the most powerful paradigms in materials science, synthesis, and modification. By developing and implementing simple, robust chemistries that do not require difficult separations or harsh conditions, the ability to form, modify, and control the structure of materials on various length scales has become more broadly available to those in the materials science community. As such, click chemistry has seen broad implementation in polymer functionalization, surface modification, block copolymer and dendrimer synthesis, biomaterials fabrication, biofunctionalization, and in many other areas of materials science. Here, the basic reactions, approaches, and applications of click chemistry in materials science are highlighted, and a brief look is taken into the future enabling developments in this field.     

Electrocapacitive Deionization: Mechanisms,Electrodes, and Cell Designs

Capacitive deionization (CDI) is an emerging water desalination technology for removing different ionic species from water, which is based on electric charge compensation by these charged species. CDI is becoming popular because it is more energy-efficient and cost-effective than other technologies, such as reverse osmosis and distillation, specifically in dealing with brackish water having low or moderate salt concentrations. Over the past decade, the CDI research field has witnessed significant advances in the used electrode materials, cell architectures, and associated mechanisms for desalination applications. This review article first discusses ion storage/removal mechanisms in carbon and Faradaic materials aided by advanced in situ analysis techniques and computations. It then summarizes research progress toward electrode materials in terms of structure, surface chemistry, and composition. More still, it discusses CDI cell architectures by highlighting their different cell design concepts. Finally, current challenges and future research directions are summarized to provide guidelines for future CDI research.