Spectrofluorimetric analysis of captopril based on its obstruction effect of the nanomaterial surface energy transfer between acridine orange and gold nanoparticles

A simple and sensitive method for detection of captopril was established based on its obstructive effect on nanomaterial sur- face energy transfer （NSET）. It was found that the acridine orange （AO） could be adsorbed onto the surface of citrated-gold nanoparticles （AuNPs） through electrostatic interaction. Incidentally, the fluorescence of AO was quenched owing to the dipole-dipole interaction of NSET between AO fluorophore and the AuNPs. However, captopril could obstruct the occurrence of NSET between AO and AuNPs effectively with the formation of Au-S covalent bonds between it and the AuNPs. Consequently, AO molecules were moved away from the surface of AuNPs leading to a decline of the energy transfer efficiency. Moreover, the fluorescence of AO could be gradually restored with the addition of captopril. Under the optimal conditions, the recovered fluorescence intensity correlated linearly with the concentration of captopril in the range of 400 nmol/L-2.0μmol/L with a detection limit of 71 μmol/L. Besides, the proposed method was successfully applied for the detection of captopril in troches with the recovery of 93%-102% and the RSD lower than 2.24%. The results were in good agreement with those obtained from the HPLC method,

The Fabrication of Microstructure Surface of Superhydrophobic Coating by Surface Gelation Technology

The microstructured surface of materials were fabricated by a two-step acid-base catalyzed sol-gel process. In fluorinated polymer with PTFE doping, the well-proportioned composite sols were prepared using sol-gel processing under the hydrochloric acid and deficiency of water conditions. After the substrate was coated by composite sols, and the gelation treatment on the surface of composite coating, the micrometer-scale and nanometer-scale hierarchical structures were formed in surface layer of material. XPS and TEM technologies were employed to identify that the gelation occurs just on the surface of composite coating. The morphology of coating surface was observed by SEM and AFM technologies. The microstructured surface of material can be fabricated using this inexpensive and easily controlled method on low surface energy resin materials, the super-hydrophobic coatings materials can be prepared.

Targeted Sub-Attomole Cancer Biomarker Detection Based on Phase Singularity 2D Nanomaterial-Enhanced Plasmonic Biosensor

Detection of small cancer biomarkers with low molecular weight and a low concentration range has always been challenging yet urgent in many clinical applications such as diagnosing early-stage cancer,monitoring treatment and detecting relapse.Here,a highly enhanced plasmonic biosensor that can overcome this challenge is developed using atomically thin two-dimensional phase change nanomaterial.By precisely engineering the configuration with atomically thin materials,the phase singularity has been successfully achieved with a significantly enhanced lateral position shift effect.Based on our knowledge,it is the first experimental demonstration of a lateral position signal change>340μm at a sensing interface from all optical techniques.With this enhanced plasmonic effect,the detection limit has been experimentally demonstrated to be 10^(-15) mol L^(−1) for TNF-α cancer marker,which has been found in various human diseases including inflammatory diseases and different kinds of cancer.The as-reported novel integration of atomically thin Ge_(2)Sb_(2)Te_(5) with plasmonic substrate, which results in a phase singularity and thus a giant lateral position shift, enables the detection of cancer markers with low molecular weight at femtomolar level. These results will definitely hold promising potential in biomedical application and clinical diagnostics.

Reiner-Rivlin nanomaterial heat transfer over a rotating disk with distinct heat source and multiple slip effects

The thermodynamic features of the Reiner-Rivlin nanoliquid flow induced by a spinning disk are analyzed numerically.The non-homogeneous two-phase nanofluid model is considered to analyze the effect of nanoparticles on the thermodynamics of the Reiner-Rivlin nanomaterial,which also includes a temperature-dependent heat source(THS)and an exponential space-dependent heat source(ESHS).Further,the transfer of heat and mass is analyzed with velocity slip,volume fraction jump,and temperature jump boundary conditions.The finite difference method-based routine is used to solve the complicated differential equations formed after using the von-Karman similarity technique.Limiting cases of the present problem are found to be in good agreement with benchmarking studies.The relationship of the pertinent parameters with the heat and mass transport is scrutinized using correlation,which is further evaluated based on the probable error estimates.Multivariable models are fitted for the friction factor at the disk and heat transport,which accurately predict the dependent variables.The Reiner-Rivlin nanoliquid temperature is influenced comparatively more by the ESHS than by THS.The Nusselt number is decreased by the ESHS and THS,whereas the friction factor at the disk is predominantly decremented by the wall roughness aspect.The increment in the non-Newtonian characteristic of the liquid leads more fluid to drain away in the radial direction far from the disk compared with the fluid nearby the disk in the presence of the centrifugal force during rotation.The increased thermal and volume fraction slip lowers the nanoliquid temperature and nanoparticle volume fraction profiles.

Ab Initio Nonadiabatic Dynamics of Semiconductor Materials via Surface Hopping Method

Photoinduced carrier dynamic processes are without doubt the main driving force responsible for the efficient performance of semiconductor nanomaterials in applications like photoconversion and photonics.Nevertheless,establishing theoretical insights into these processes is computationally challenging owing to the multiple factors involved in the processes,namely reaction rate,material surface area,material composition etc.Modelling of photoinduced carrier dynamic processes can be performed via nonadiabatic molecular dynamics(NA-MD)methods,which are methods specifically designed to solve the time-dependent Schrodinger equation with the inclusion of nonadiabatic couplings.Among NA-MD methods,surface hopping methods have been proven to be a mighty tool to mimic the competitive nonadiabatic processes in semiconductor nanomaterials,a worth noticing feature is its exceptional balance between accuracy and computational cost.Consequently,surface hopping is the method of choice for modelling ultrafast dynamics and more complex phenomena like charge separation in Janus transition metal dichalcogenides-based van der Waals heterojunction materials.Covering latest stateof-the-art numerical simulations along with experimental results in the field,this review aims to provide a basic understanding of the tight relation between semiconductor nanomaterials and the proper simulation of their properties via surface hopping methods.Special stress is put on emerging state-ot-the-art techniques.By highlighting the challenge imposed by new materials,we depict emerging creative approaches,including high-level electronic structure methods and NA-MD methods to model nonadiabatic systems with high complexity.

Research on Effect of Adding Nanomaterial to Propellant on Gun Barrel

The barrel lifes of three small caliber rifles were tested by using the propellant with nanomaterial and the standard propellant respectively. The test results show that the service life increases observably due to adding nanomaterial to the propellant. Then, the influence of the nanomaterial on the tube was researched by splitting the two barrels tested and detecting their inner surfaces. It was found that the erosion of the barrel bore is reduced observably by using the propellant with nanomaterial. And it makes the volume and the size of the gun chamber change less. Therefore, the barrel life can be prolonged by adding the nanomaterial in the propellant.

Engineering a Localized Surface Plasmon Resonance Platform for Molecular Biosensing

In this work, we introduce a new perspective on the development of Localized Surface Plasmon Resonance (LSPR) optical biosensors. Computational simulations, focused on the assessment of the LSPR spectrum and spatial distribution of the electromagnetic field enhancement near a metallic nanoparticle, elucidated the behavior of crucial parameters, as figure of merit, bulk and molecular sensitivity, which governs a LSPR sensor performance. Gold and silver nanospheres were explored as starting point to assess plasmonic optical characteristics of the nanostructured sensor platform. Here, for the first time in the literature, Campbell’s model was evaluated exploiting a NP size-dependence approach. The theoretical analyses indicate a nonlinear behavior of the bulk and molecular sensitivity as function of the NP size. Substantial LSPR peak shifts due to the adsorption of molecules layer on a NP surface were observed for nanoparticles with ~5 nm and ~40 nm radius. Moreover, on molecular sensing, LSPR peak shift is also determined by the thickness of adsorbed molecular shell layers. We observed that for 40 nm radius gold and silver nanospheres, significant LSPR peak shift could be induced by small (few nm) thickness change of the adsorbate shell layer. Moreover, this work provides insights on the LSPR behavior due to adsorption of molecular layer on a NP surface, establishing a new paradigm on engineering LSPR biosensor. Furthermore, the proposed approach can be extended to engineer an efficiently use of different nanostructures on molecular sensing.

Two-dimensional silicon nanomaterials for optoelectronics

Silicon nanomaterials have been of immense interest in the last few decades due to their remarkable optoelectronic responses,elemental abundance,and higher biocompatibility.Two-dimensional silicon is one of the new allotropes of silicon and has many compelling properties such as quantum-confined photoluminescence,high charge carrier mobilities,anisotropic electronic and magnetic response,and non-linear optical properties.This review summarizes the recent advances in the synthesis of two-dimensional silicon nanomaterials with a range of structures(silicene,silicane,and multilayered silicon),surface ligand engineering,and corresponding optoelectronic applications.

Effective desalination and anti-biofouling performance via surface immobilized MWCNTs on RO membrane

Desalination is considered a viable method to overcome the issue of water scarcity either from waste water or seawater. For this purpose, this study employed a facile approach to develop surface immobilized oxidized-MWCNTs(o-MWCNTs) onto crosslinked polyvinyl alcohol(PVA) membrane. Firstly, modified polysulphone substrate was synthesized on to which crosslinked PVA layer was spread onto it. PVA layer act as active layer for surface immobilization of o-MWCNTs in varying concentration. The functional group analysis, morphology and roughness of membranes surface was conducted out using FTIR, SEM and AFM respectively. The results showed that modified membranes, immobilized o-MWCNTs enhanced the salt rejection(Na_(2)SO_(4)) upto 99.8%. After contacting with Escherichia coli and Staphylococcus aureus for 2.5 h the bacteria mortalities of the fabricated membrane could reach 96.9%. Furthermore, the antibiofouling tests showed that OP-MWCNTs(1-5) modified membranes have higher anti-biofouling property than the control membrane.

Noble-metal free plasmonic nanomaterials for enhanced photocatalytic applications—A review

Plasmonic nanomaterial catalysis is currently at the frontier of photocatalysis,overcoming the limitations of wide bandgap semiconductors for light absorption.Its localized surface plasmon resonance(LSPR)properties allow broad ultraviolet-visible-near infrared ray(UV-vis-NIR)absorption,making it an ideal material for solar energy conversion.Most plasmonic nanostructures rely on precious metals.Although noble metal plasmonic nanomaterials have proven to be one of the strategies for enhancing photocatalytic activity,their expensive cost and limitations in light absorption range have hindered their practical application.As a result,noble-metal free plasmonic nanomaterials have risen to the top of the research priority list.Therefore,this paper reviews the fundamental principles and classification of the LSPR effect of noble-metal free plasmonic nanomaterials in photocatalytic and their recent applications in hydrogen generation,carbon dioxide reduction,and pollutant degradation.Specific cases elucidate the possible working mechanism of enhanced photocatalysis by noble-metal free plasmonic nanomaterials.Finally,the challenges and future opportunities for noble-metal free plasmonic nanomaterials in energy conversion and storage are discussed and envisioned.

Continuous morphing trailing-edge wing concept based on multi-stable nanomaterial

Morphing technology is one of the most effective methods to improve the flight efficiency of aircraft.Traditional control surfaces based morphing method is mature and widely used on current civil and military aircraft,but insufficiently effective for the entire flight envelope.Recent research on morphing wing still faces the challenge that the skin material for morphing should be both deformable and stiff.In this study,a continuous morphing trailing-edge wing with a new multi-stable nano skin material fabricated using surface mechanical attrition treatment technology was proposed and designed.Computational fluid dynamics simulation was used to study the aerodynamic performance of the continuous morphing trailing-edge wing.Results show that the lift coefficient increases with the increase of deflection angle and so does the lift-drag ratio at a small angle of attack.More importantly,compared with the wing using flaps,the continuous morphing trailing-edge wing can reduce drag during the morphing process and its overall aerodynamic performance is improved at a large angle of attack range.Flow field analysis reveals that the continuous morphing method can delay flow separation in some situations.

A general, rapid and solvent-free approach to fabricating nanostructured polymer surfaces

A general, rapid and solvent-free approach is proposed to fabricate nanostructured polymer surfaces by coupling ultrasonic vi- bration and anodized aluminum oxide templating. With our approach, hollow nanorods or nanofibers with controlled diameter and length are prepared on polymer surfaces. The whole fabrication process is completed in ～30 s and equally applicable to polymers of different crystalline structures. The wettability of the as-fabricated polymer surfaces （being hydrophilic, hydro- phobic, highly hydrophobic or even superhydrophobic） is readily regulated by adjusting the welding time from 0 s to a maxi- mum of 10 s. Our approach can be a promising industrial basis for manufacturing functional nanomaterials in the fields of electronics, optics, sensors, biology, medicine, coating, or fluidic technologies.

Stable and unique graphitic Raman internal standard nanocapsules for surface-enhanced Raman spectroscopy quantitative analysis

Graphitic nanomaterials have unique, strong, and stable Raman vibrations that have been widely applied in chemistry and biomedicine. However, utilizing them as internal standards （ISs） to improve the accuracy of surface-enhanced Raman spectroscopy （SERS） analysis has not been attempted. Herein, we report the design of a unique IS nanostructure consisting of a large number of gold nanoparticles （AuNPs） decorated on multilayered graphitic magnetic nanocapsules （AGNs） to quantify the analyte and eliminate the problems associated with traditional ISs. The AGNs demonstrated a unique Raman band from the graphitic component, which was localized in the Raman silent region of the biomolecules, making them an ideal IS for quantitative Raman analysis without any background interference. The IS signal from the AGNs also indicated superior stability, even under harsh conditions. With the enhancement of the decorated AuNPs, the AGN nanostructures greatly improved the quantitative accuracy of SERS, in particular the exclusion of quantitative errors resulting from collection loss and non-uniform distribution of the analytes. The AGNs were further utilized for cell staining and Raman imaging, and they showed great promise for applications in biomedicine.

Electrostabilized homogeneous dispersion of boron nitride nanotubes in wide-range of solvents achieved by surface polarity modulation through pyridine attachment

Boron nitride nanotubes(BNNTs)show exceptional physical properties including high mechanical strength and thermal conductivity;however,their applications have been restricted due to limited dispersibility in processing solvents.Here,a novel BNNT dispersion method with exceptional dispersibility in a wide range of solvents has been demonstrated by surtace polarity modulation through short-molecule pyridine attachment.Nitrogen atoms in pyridine are selectively bonded to electron-deficient boron atoms of the BNNT surface through Lewis acid-base reaction,which changes the surface polarity of BNNTs from neutral to negative.Re-dispersing pyridine-attached BNNTs(Py-BNNTs)create a thick and stable electronic double layer(EDL),resulting in uniform dispersion of BNNTs in solvents with an exceptional solubility parameter range of 18.5-48 MPa^1/2.The uniform dispersion of BNNTs is maintained even after the mixing with diverse polymers.Finally,composites incorporating uniformly-distributed BNNTs have been realized,and extraordinary property enhancements have been observed.The thermal conductivity of 20 wt.%Py-BNNT/epoxy composite has been significantly improved by 69.6%and the tensile strength of 2 wt.%Py-BNNT/PVA has been dramatically improved by 75.3%.Our work demonstrates a simple and facile route to dispersing BNNTs in diverse solvents,consequently leading to selective utlization of BNNT dispersed solvents in various application fields.

Biomedical Effects and Nanomaterials： Nanosafety of Engineered Recent Progress

With the development of nanotechnology, there are growing concerns about biological effects and biosafety of engineered nanomaterials. On the other hand, nanoparticles are widely used in medical fields based on their novel interactions with biological entities. However, there are still a lot of challenges to establish systematic knowledge about nanotoxicology and develop biologically safer biomedical materials due to the variety of factors determining their biomedical effects and nanotoxicity. Understanding the interactions of engineered nanomaterials with the bio- logical entities becomes crucial to the further development of nanoscience and nanotechnology. In the past decade, colleagues in our laboratory intensively studied the toxic properties of various kinds of nanomaterials and their chemical mechanisms. In this paper we review the recent advance in the research on the biological effects of engi- neered nanomaterials and nanosafety issue, by focusing on the studies about representative nanomaterials in our la- boratory.

A novel Cu_(1.5)Mn_(1.5)O_(4)photothermal catalyst with boosted surface lattice oxygen activation for efficiently photothermal mineralization of toluene

Developing a novel photothermal catalyst for efficient mineralization of volatile organic compounds(VOCs)is of great significance to control air pollution.Herein,for the first-time,a spinel Cu_(1.5)Mn_(1.5)O_(4)nanomaterial with enhanced surface lattice oxygen activation was successfully obtained by a novel light-driven in situ reconstruction strategy from its precursor(CuMnO_(2))for efficient toluene mineralization.X-ray diffraction(XRD)and high-resolution transmission electron microscopy(HRTEM)analyses confirm that the CuMnO_(2)phase was converted into spinel Cu1.5Mn1.5O4 phase under full spectrum light irradiation.Ultraviolet–visible–near infrared ray(UV–vis–NIR)spectroscopy,X-ray photoelectron spectroscopy(XPS)analysis,and density functional theory(DFT)calculations determine that the strong near-infrared absorption ability and low dissociation energy of oxygen bond in Cu_(1.5)Mn_(1.5)O_(4)are beneficial to its surface lattice oxygen activation.Furthermore,O2-temperature programmed desorption(TPD)and in situ diffuse reflectance infrared transform spectroscopy(DRIFTS)further indicate that the surface lattice oxygen of the Cu_(1.5)Mn_(1.5)O_(4)is easily activated under light irradiation,which can promote ring opening of toluene.This research endows a new design of photothermal nanomaterial with enhanced lattice oxygen activation for deep oxidation of VOCs.

Thin Films for Coating Nanomaterials

For nano-structured solids （those with one or more dimensions in the 1-100 nm range）, attempts of surface modification can pose significant and new challenges. In traditional materials, the surface coating could be several hundreds nanometers in thickness, or even microns and millimeters. In a nano-structured material, such as particle or nanofibers, the coating thickness has to be substantially smaller than the bulk dimensions （100 nm or less）, yet be durable and effective. In this paper, some aspects of effective nanometer scale coatings have been discussed. These films have been deposited by a non-line of sight （plasma） techniques; and therefore, they are capable of modifying nanofibers, near net shape cellular foams, and other high porosity materials. Two types of coatings will be focused upon： （a） those that make the surface inert and （b） those designed to enhance surface reactivity and bonding. The former has been achieved by forming 1-2 nm layer of --CF2- （and/or CF3） groups on the surface, and the latter by creating a nano- layer of SiO2-type compound. Nucleation and growth studies of the plasma-generated film indicate that they start forming as 2-3 nm high islands that grow laterally, and eventually completely cover the surface with 2-3 nm film. Contact angle measurements indicate that these nano-coatings are fully functional even before they have achieved complete coverage of 2-3 nm. They should therefore be applicable to nano-structural solids. This is corroborated by application of these films on vapor grown nanofibers of carbon, and on graphitic foams. Coated and uncoated materials are infiltrated with epoxy matrix to form composites and their microstructure, as well as mechanical behaviors are compared. The results show that the nano-oxide coating can significantly enhance bond formation between carbon and organic phases, thereby enhancing wettability, dispersion, and composite behavior. The fluorocarbon coating, as expected, reduces bond formation, and therefore, effective as an inert layer to passivate nanomaterials.

纳米材料增强植物纤维复合材料研究进展

对近4年来纳米材料增强植物纤维复合材料制备方法进行了综述。纳米材料增强植物纤维复合材料的制备方法主要包括硅烷偶联剂处理、溶胶-凝胶法、化学接枝法、横穿结晶技术和机械混杂法,总结了各种方法的优缺点,讨论了纳米纤维增强植物纤维复合材料制备过程中存在的问题,最后展望了纳米材料增强植物纤维复合材料未来的发展方向。

POSS改性氧化石墨烯对涂层防腐和疏水性能的影响

通过有机硅化合物γ-氨丙基三乙氧基硅烷(APTES)自水解缩合制得有机-无机杂化材料笼型倍半硅氧烷(POSS),将其接枝到氧化石墨烯(graphene oxide,GO)上以克服GO的聚集,利用Boehm滴定法测定接枝率为98.3%,进一步负载锌离子制得复合纳米粒子POSS/GO/Zn。通过FT-IR、XRD、Raman、NMR和SEM对POSS/GO/Zn结构及微观形貌进行了表征,并将其应用在水性环氧树脂(WEP)涂层材料中,电化学阻抗谱(EIS)和水接触角测试结果表明,所制得的纳米粒子的复合涂层具有优异的防腐和疏水性能,在3.5%氯化钠溶液中浸泡40 d后POSS/GO/Zn/WEP的阻抗值为8.33×10^(5)Ω·cm^(2),大于空白环氧涂层浸泡第一天的初始值1.46×10^(5)Ω·cm^(2),水接触角由48.42°增大至98.11°,涂层由亲水转为疏水特性,表明该材料在涂层材料中具有良好的应用潜能。

准一维纳米发光材料制备与分析方法

准一维纳米材料由于两个方向的限域作用,一维纳米材料的电子结构,能带结构与常规的微米材料不同,因而受到广泛的关注。对于纳米发光材料而言,将发光材料制成纳米材料后,材料的发光一般会明显减弱。当材料制成准一维纳米材料后,会大幅弥补这一缺陷。另一方面,准一维纳米发光材料会因为表面原子排列较为疏松,容易出现各种晶体缺陷,而出现常规材料不会出现的光学性能。所以准一维纳米发光材料的研究,受到广泛的兴趣。本文将综述准一维纳米材料的发展历史、制备方法和分析表征方法。