Femtosecond Laser Thermal Accumulation-Triggered Micro-/Nanostructures with Patternable and Controllable Wettability Towards Liquid Manipulating

Versatile liquid manipulating surfaces combining patternable and controllable wettability have recently motivated considerable attention owing to their significant advantages in droplet-solid impacting behaviors,microdroplet self-removal,and liquid–liquid interface reaction applications.However,developing a facile and efficient method to fabricate these versatile surfaces remains an enormous challenge.In this paper,a strategy for the fabrication of liquid manipulating surfaces with patternable and controllable wettability on Polyimide(PI)film based on femtosecond laser thermal accumulation engineering is proposed.Because of its controllable micro-/nanostructures and chemical composition through adjusting the local thermal accumulation,the wettability of PI film can be tuned from superhydrophilicity(~3.6°)to superhydrophobicity(~151.6°).Furthermore,three diverse surfaces with patternable and heterogeneous wettability were constructed and various applications were successfully realized,including water transport,droplet arrays,and liquid wells.This work may provide a facile strategy for achieving patternable and controllable wettability efficiently and developing multifunctional liquid steering surfaces.

Nanostructured Ternary Metal Tungstate-Based Photocatalysts for Environmental Purification and Solar Water Splitting:A Review

Visible-light-responsive ternary metal tungstate(MWO_4) photocatalysts are being increasingly investigated for energy conversion and environmental purification applications owing to their striking features, including low cost,eco-friendliness, and high stability under acidic and oxidative conditions. However, rapid recombination of photoinduced electron–hole pairs and a narrow light response range to the solar spectrum lead to low photocatalytic activity of MWO_4-based materials, thus significantly hampering their wide usage in practice. To enable their widespread practical usage, significant efforts have been devoted, by developing new concepts and innovative strategies. In this review, we aim to provide an integrated overview of the fundamentals and recent progress of MWO_4-based photocatalysts. Furthermore, different strategies, including morphological control, surface modification, heteroatom doping, and heterojunction fabrication, which are employed to promote the photocatalyticactivities of MWO_4-based materials, are systematically summarized and discussed. Finally, existing challenges and a future perspective are also provided to shed light on the development of highly efficient MWO_4-based photocatalysts.

Bioinspired micro/nanostructured surfaces prepared by femtosecond laser direct writing for multi-functional applications

manufacturing of biomimetic micro/nanostructures due to its specific advantages including high precision,simplicity,and compatibility for diverse materials in comparison with other methods(e.g.ion etching,sol-gel process,chemical vapor deposition,template method,and self-assembly).These biomimetic micro/nanostructured surfaces are of significant interest for academic and industrial research due to their wide range of potential applications,including self-cleaning surfaces,oil-water separation,and fog collection.This review presents the inherent relationship between natural organisms,fabrication methods,micro/nanostructures and their potential applications.Thereafter,we throw a list of current fabrication strategies so as to highlight the advantages of FLDW in manufacturing bioinspired microstructured surfaces.Subsequently,we summarize a variety of typical bioinspired designs(e.g.lotus leaf,pitcher plant,rice leaf,butterfly wings,etc)for diverse multifunctional micro/nanostructures through extreme femtosecond laser processing technology.Based on the principle of interfacial chemistry and geometrical optics,we discuss the potential applications of these functional micro/nanostructures and assess the underlying challenges and opportunities in the extreme fabrication of bioinspired micro/nanostructures by FLDW.This review concludes with a follow up and an outlook of femtosecond laser processing in biomimetic domains.

激光冲击强化技术研究和多尺度模拟综述

激光冲击强化技术是一种利用高功率密度和短脉冲的激光对材料表面进行强化处理的新型表面改性技术,能够在材料表面形成梯度纳米结构并产生有益的梯度残余压应力场,有效提高材料的力学性能。本文介绍了激光冲击强化技术的发展历史和研究现状,并就该技术的应用前景进行了展望。随后,分析了激光冲击强化技术的原理,并分析了激光冲击诱导产生的残余应力和梯度纳米结构对材料的强化作用。综述了激光冲击强化技术对材料强韧性、抗疲劳性、耐磨性和抗应力腐蚀开裂能力的影响,最后从宏观、介观、细观、微观和纳观5个尺度介绍了激光冲击强化技术的多尺度模拟研究,并对比了不同尺度模拟手段的差异。

Recent advances in electrochemiluminescence imaging analysis based on nanomaterials and micro-/nanostructures

Electrochemiluminescence(ECL) is a kind of luminescent phenomenon caused by electrochemical reactions. Based on the advantages of ECL including low background, high sensitivity, strong spatiotemporal controllability and simple operation, ECL imaging is able to visualize the ECL process,which can additionally achieve high throughput, fast and visual analysis. With the development of optical imaging technique, ECL imaging at micro-or nanoscale has been successfully applied in immunoassay,cell imaging, biochemical analysis, single-nanoparticle detection and study of mechanisms and kinetics of reactions, which has attracted extensive attention. In this review, the basic principles and apparatus of ECL imaging were briefly introduced at first. Then several latest and representative applications of ECL imaging based on nanomaterials and micro-/nanostructures were overviewed. Finally, the superiorities and challenges in ECL imaging for further development were discussed.

Intrinsic Peroxidase-like Activity of Porous CuO Micro-/nanostructures with Clean Surface

Porous CuO micro-/nanostructures with clean surface,prepared through Cu_(2)(OH)_(2)CO_(3) precursor followed by calcination in air,were proven to be an effective peroxidase mimic.They can quickly catalyze oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine(TMB)in the presence of H_(2)O_(2),producing a blue color.The obtained porous CuO micro-/nanostructure have potential application in wastewater treatment.The apparent steady-state kinetic parameter was studied with TMB as the substrate.In addition,the potential application of the porous CuO in wastewater treatment was demonstrated with phenol-containing water as an example.Such investigation not only confirms the intrinsic peroxidase-like activity of micro-/nanostructured CuO,but also suggests its potential application in wastewater treatment.

生物材料力学研究新进展

作为生物力学中一个快速发展的重要研究领域,生物材料力学旨在通过实验研究和理论分析,揭示各种天然生物材料的功能、性能、结构和组分之间的基本关系和机理,并为新材料的仿生设计等提供来自大自然的启示。本文综述了近年来我国学者在该领域取得的一些最新研究进展,主要内容包括珍珠母、牛角等生物复合材料的强韧化机制,生物材料表面浸润特性与微纳米结构之间的关系,以及相关的一些仿生应用。本文还简要介绍了本期专刊所刊登的7篇邀请文章。

叠层圆柱台表面等离激元器件的共振特性

基于金属纳米结构增强光与物质的相互作用,调控光学响应是光学前沿研究。金属纳米结构能显著增强电磁场和热点空间位置调控,是表面等离激元器件应用的关键。借鉴衍射光学元件设计思想,文中提出一种简单的多尺度叠层圆柱台(double stacked nanocone,DSC)金属纳米结构,实现近/远场深度调控。在给定激发条件下,DSC纳米结构中腔模与局域表面等离激元模式间产生杂化,实现多尺度级联场增强,远场响应也得到有效调制,且"热点"能有效地定位到纳米结构的上表面。进一步,提出并研究了掩模重构的纳米加工方法,低成本、可控地制备了DSC纳米结构,工艺控制是三台阶DSC器件特性的关键,实验结果与理论设计一致。

常/微重力下微结构表面强化沸腾换热研究进展

表面改性是提高沸腾换热性能的重要手段。本文以自主开发的微结构表面为基础,简述了近三年来常重力条件下的微/纳结构表面强化池沸腾换热、临界热流密度预测模型及经验关联、微重力条件下(重力水平为10^(-2)～10^(-3)g0,g0=9.8m/s^2)加热面尺寸对沸腾换热的影响和气泡动力学等方面的研究进展。对柱状微结构参数和排布方式进行优化后的多尺度复合微结构表面相比柱状微结构表面和光滑表面,其壁面温度可分别降低8K和30K以上,而临界热流密度(CHF)则分别提高了28%和119%以上。体积分数为0.02%的乙醇/银纳米流体相对于单纯的乙醇工质,相同条件下换热壁面温度可降低8～15K,而机械作用对CHF约有25%的提高。通过对柱状微结构的几何参数以及临界发生时的供液机理研究,建立了考虑柱状微结构参数的CHF关联式、微/纳结构表面考虑液体毛细芯吸作用的CHF预测模型以及考虑液体铺展速度的CHF预测关联式。根据微重力下加热面尺寸对沸腾的影响的研究,提出了基于恒定热流密度的换热预测关联式。考虑微重力条件下主气泡和小气泡的表面张力,对传统的气泡脱离直径预测的力平衡模型进行了改进,进一步提高了微重力下气泡的脱离半径的预测精度。此外,对近年来以FC-72为工质的其他强化池沸腾换热微结构表面的研究成果进行了总结,并与自主研发的微结构表面换热性能进行了对比与分析,为今后的研究方向和应用指出了方向。

纳米修饰吸液芯超薄平板热管的传热特性

研制了一种总厚度为1.30 mm的新型超薄平板热管(UTFHP),其内部吸液芯是多孔介质底层(PL)和多孔介质丝(PW)组成的多尺度复合结构。经过化学改性处理,吸液芯表面生成纳米结构,具有超亲水特性。对热管的热性能进行实验研究,分析纳米结构、充液比以及角度对热性能的影响。结果表明,充液比为25%时,与未改性的热管相比,改性热管的临界热通量(CHF)提高了255%、总热阻最大可降低43.2%;纳米结构降低了冷凝段热阻,但在小功率时增大了蒸发段热阻。在高充液比时,纳米结构抑制热管的传热性能。角度对热管的热性能影响较大,当蒸发段位于冷凝段的正下方时,热管的热性能最佳。未改性和改性的热管都具有良好的传热特性,最高功率分别为83.7和44.3 W。

层次孔碳材料:结构设计、功能改性及新能源器件应用

发展电化学能源存储与转换技术是我国的长期重大需求。作为电化学能源器件中的关键材料,多孔碳材料已成为当前能源材料与化工领域的研究热点。层次孔碳材料是一类新型的多孔碳材料,同时兼具不同尺寸与功能的微孔、中孔或大孔。研究者通过对层次孔碳材料可控设计,已制得一系列孔结构、孔骨架及表面化学性质和微/纳拓扑形貌各异的新型层次孔碳及其复合材料,极大地提升了其能源存储和转化性能。本综述总结了近年来有关层次孔碳材料的结构设计、可控制备及其在电化学能源器件应用领域等方面的研究进展,并对其未来发展提出了建议与展望。

Metal–Organic Framework-Based Sensors for Environmental Contaminant Sensing

Increasing demand for timely and accurate environmental pollution monitoring and control requires new sensing techniques with outstanding performance, i.e.,high sensitivity, high selectivity, and reliability. Metal–organic frameworks(MOFs), also known as porous coordination polymers, are a fascinating class of highly ordered crystalline coordination polymers formed by the coordination of metal ions/clusters and organic bridging linkers/ligands. Owing to their unique structures and properties,i.e., high surface area, tailorable pore size, high density of active sites, and high catalytic activity, various MOF-based sensing platforms have been reported for environmental contaminant detection including anions, heavy metal ions,organic compounds, and gases. In this review, recent progress in MOF-based environmental sensors is introduced with a focus on optical, electrochemical, and field-effect transistor sensors. The sensors have shown unique and promising performance in water and gas contaminant sensing. Moreover, by incorporation with other functional materials, MOF-based composites can greatly improve the sensor performance. The current limitations and future directions of MOF-based sensors are also discussed.

In-situ design and construction of lithium-ion battery electrodes on metal substrates with enhanced performances：A brief review

For the ever-growing demand of advanced lithium-ion batteries, it is highly desirable to grow self-supported micro-/nanostructured arrays on metal substrates as electrodes directly. The in-situ growth of electrode materials on the conducting substrates greatly simplifies the electrode fabrication process without using any binders or conductive additives. Moreover, the well-ordered arrays closely connected to the current collectors can provide direct electron transport pathways and enhanced accommodation of strains arisen from lithium ion lithiation/delithiation. This article summarizes our recent work on design and construction of lithium-ion battery electrodes on metal substrates. An aqueous solution-based process and a microemulsion-mediated process have been respectively presented to control the kinetic and thermodynamic processes for the micro-/nanostructured array growth on metal substrates, with particular attention to CuO nanorod arrays and microcog arrays successfully prepared on Cu foil substrates. They can be directly used as binder-free electrodes to build advanced lithium-ion batteries with high energy, high safety and high stability.

PERSPECTIVES IN MECHANICS OF HETEROGENEOUS SOLIDS

The Micro- and Nano-mechanics Working Group of the Chinese Society of Theoretical and Applied Mechanics organized a forum to discuss the perspectives, trends, and directions in mechanics of heterogeneous materials in January 2010. The international journal, Acta Mechanica Solida Sinica, is de- voted to all fields of solid mechanics and relevant disciplines in science, technology, and engineering, with a balanced coverage on analytical, experimental, numerical and applied investigations. On the occasion of the 30TM anniversary of Acta Mechanica Solida Sinica, its editor-in-chief, Professor Q.S. Zheng invited some of the forum participants to review the state-of-the-art of mechanics of heterogeneous solids, with a particular emphasis on the recent research development results of Chinese scientists. Their reviews are organized into five research areas as reported in different sections of this paper. ~I firstly brings in fo- cus on micro- and nano-mechanics, with regards to several selective topics, including multiscale coupled models and computational methods, nanocrystal superlattices, surface effects, micromechanical damage mechanics, and microstructural evolution of metals and shape memory alloys. ~II shows discussions on multifield coupled mechanical phenomena, e.g., multi-fields actuations of liquid crystal polymer networks, mechanical behavior of materials under radiations, and micromechanics of heterogeneous materials. In ~III, we mainly address the multiscale mechanics of biological nanocomposites, biological adhesive surface mechanics, wetting and dewetting phenomena on microstructured solid surfaces. The phononic crystals and manipulation of elastic waves were elaborated in ~IV. Finally, we conclude with a series of perspectives on solid mechanics. This review will set a primary goal of future science research and engineering application on solid mechanics with the effort of social and economic development.

Reduced graphene oxide-supported CoP nanocrystals confined in porous nitrogen-doped carbon nanowire for highly enhanced lithium/sodium storage and hydrogen evolution reaction

Rational synthesis of a hierarchical porous architecture with highly active and consecutive conductive network is very critical to achieve the high-performance of nanomaterials in electrochemical energy conversion and storage.We propose here a hierarchical micro-/nanostructured hybrids constructed by the dual carbon shell nanowire host containing CoP nanocrystals of several nanometers,which generates Co-based metal-organic framework on graphene oxide nanosheets in situ and followed a direct phosphorization(CoP@NC/rGO).The dual carbon shell,consisting of Co-based metal-organic framework derived porous doped carbon(NC)and reduced graphene oxide(rGO),can not only impedes CoP nanocrystals from coalescing,and renders highly exposed the electrochemically accessible active sites,but also provides the multidimensional pathways for rapid electron and ion transportation.More importantly,the covered dual carbon shell on CoP nanocrystals plays a role as a protective layer to impede the nanocrystals’corrosion.By virtue of compositional and structural advantages,the micro-/nanostructured CoP@NC/rGO hybrids manifest outstanding energy storage properties when evaluated as anodes for lithium/sodium ion batteries.Remarkably,it also reveals highly efficient electrocatalytic performance for hydrogen evolution reaction in acid media with low Tafel slope,overpotential and robust durability.

飞秒激光诱导钛表面可控微纳结构用于水下气泡操纵

针对典型金属材料钛,利用自主搭建的飞秒激光振镜扫描加工系统,加工了具有特定形貌特征的多尺度微纳结构.在此基础上对多尺度微纳结构的可逆润湿性及水下气泡操纵特性进行了实验探究,并从微观界面化学的角度阐释了可逆润湿性的调谐机理.研究结果表明:在飞秒激光烧蚀挤压作用下,钛表面诱导的多尺度微纳结构对原始表面的润湿性具有放大效应,固液接触角减小,水下气泡接触角增大;在辅助加热条件下,固液接触角增大,水下气泡接触角同时减小,气泡在表面完全铺展;随后将超疏水表面置于紫外灯下曝光,多尺度微纳结构上的液体接触角又开始减小,并最终实现了超疏水到超亲水性以及水下超亲气到超疏气的可逆调谐.另外,液体接触角与水下气泡接触角的可逆调谐特性呈现相反的变化趋势,这与固液气三相接触线的移动机制密切相关.本文对实现钛表面微纳结构设计与调控,提高具有可逆润湿性的金属表面在水下气泡操纵与收集,以及污水处理等领域的应用都具有重要意义.

梯度纳米结构金属力学性能、变形机理和多尺度计算研究进展

近年来,梯度纳米结构金属因其优越的力学性能和独特的塑性变形机理受到广泛关注,已成为材料与力学学科的热点和前沿.论文首先介绍梯度纳米结构金属的强度、塑性、加工硬化和抗疲劳等核心力学性能,以及晶粒长大、塑性应变梯度和几何必需位错等塑性变形机理及其力学研究.其次介绍梯度纳米结构金属的多尺度计算与模拟研究.最后讨论梯度纳米结构金属研究领域存在的挑战.

Characterization and evaluation of a femtosecond laser-induced osseointegration and an anti-inflammatory structure generated on a titanium alloy

Cell–material interactions during early osseointegration of the bone–implant interface are critical and involve crosstalk between osteoblasts and osteoclasts.The surface properties of titanium implants also play a critical role in cell–material interactions.In this study,femtosecond laser treatment and sandblasting were used to alter the surface morphology,roughness and wettability of a titanium alloy.Osteoblasts and osteoclasts were then cultured on the resulting titanium alloy disks.Four disk groups were tested:a polished titanium alloy(pTi)control;a hydrophilic micro-dislocation titanium alloy(sandblasted Ti(STi));a hydrophobic nano-mastoid Ti alloy(femtosecond laser-treated Ti(FTi));and a hydrophilic hierarchical hybrid micro-/nanostructured Ti alloy[femtosecond laser-treated and sandblasted Ti(FSTi)].The titanium surface treated by the femtosecond laser and sandblasting showed higher biomineralization activity and lower cytotoxicity in simulated body fluid and lactate dehydrogenase assays.Compared to the control surface,the multifunctional titanium surface induced a better cellular response in terms of proliferation,differentiation,mineralization and collagen secretion.Further investigation of macrophage polarization revealed that increased anti-inflammatory factor secretion and decreased proinflammatory factor secretion occurred in the early response of macrophages.Based on the above results,the synergistic effect of the surface properties produced an excellent cellular response at the bone–implant interface,which was mainly reflected by the promotion of early ossteointegration andmacrophage polarization.