Recent Progress of Fabrication,Characterization,and Applications of Anodic Aluminum Oxide(AAO)Membrane:A Review

The progress of membrane technology with the development of membranes with controlled parameters led to porous membranes.These membranes can be formed using different methods and have numerous applications in science and technology.Anodization of aluminum in this aspect is an electro-synthetic process that changes the surface of the metal through oxidation to deliver an anodic oxide layer.This process results in a self-coordinated,exceptional cluster of round and hollow formed pores with controllable pore widths,periodicity,and thickness.Categorization in barrier type and porous type films,and different methods for the preparation of membranes,have been discussed.After the initial introduction,the paper proceeds with a brief overview of anodizing process.That engages anodic aluminum oxide(AAO)layers to be used as formats in various nanotechnology applications without the necessity for expensive lithographical systems.This review article surveys the current status of the investigation on AAO membranes.A comprehensive analysis is performed on AAO membranes in applications;filtration,sensors,drug delivery,template-assisted growth of various nanostructures.Their multiple usages in nanotechnology have also been discussed to gather nanomaterials and devices or unite theminto specific applications,such as nano-electronic gadgets,channel layers,and clinical platforms tissue designing.From this review,the fact that the specified enhancement of properties of AAO can be done by varying geometric parameters of AAO has been highlighted.No review paper focused on a detailed discussion of multiple applications of AAO with prospects and challenges.Also,it is a challenge for the research community to compare results reported in the literature.This paper provides tables for easy comparison of reported applications with membrane parameters.This review paper represents the formation,properties,applications with objective consideration of the prospects and challenges of AAO applications.The prospects may appeal to researchers to promote the development of unique membranes with functionalization and controlled geometric parameters and check the feasibility of the AAO membranes in nanotechnology and devices.

PHASE-FIELD SIMULATION FOR MICROSTRUCTURAL DEVELOPMENT OF TEXTURED CERAMICS PREPARED BY REACTION TEMPLATED GRAIN GROWTH

A modified model using phase-field method in order to describe the microstructural development for the reaction templated grain growth process was developed.The current model well expressed anisotropic enlargement of the template particles.The initial parameters such as the matrix particles size,the template particles size,fraction,aspect ratio of the template particles and porosity were examined.The simulation results show that the fraction of oriented grains increases with decreasing the matrix particles size and porosity,and increasing the fraction of the initial template particles.An increase for the aspect ratio of template particles gives rise to the anisotropic microstructure development.The study suggests that the simulation results would give a guiding principle in terms of the initial preparation conditions for the textured ceramics having both a large fraction of oriented grains and anisotropic microstructure.

High transmittance and grain-orientated alumina ceramics fabricated by adding fine template particles

Transparent Al_(2)O_(3) ceramics with grains aligned to the c-axis were prepared by adding platelets with a low aspect ratio into fine equiaxed particles.The mixed powders were formed into green bodies using spontaneous coagulation casting and sintered by pressureless sintering and hot-isostatic pressure sintering.Zeta potentials and rheological behavior of the slurries,relative densities of green bodies,and orientation and optical properties of sintered bodies were investigated and discussed.The platelet with a high aspect ratio suppressed densification more seriously during sintering than the one with a low aspect ratio.An excellent oriented structure was obtained when 5 wt%platelets with a low aspect ratio were added,and transparent Al_(2)O_(3) ceramics with grains aligned to c-axis were successfully prepared;the in-line transmittance was 78.4%at 600 nm,which is the highest one in the currently reported literature.

Mesoscopic Models of Plants Composed of Metallic Nanowires

Various metallic structures of complex shape resembling living plant organisms （biomimetics） are produced as a result of self-assembly of nanowires growing on porous membranes in the course of pulse current electrodeposition. These structures occur if the electroplating is continued after the nanowires appear on the membrane surface. By varying the membrane ge- ometry, pulse current electroplating parameters, and alternating electrodeposition from two baths composed of a variety of electrolytes, diverse models were fabricated, including a hollow container with a wall thickness of 10 nm 20 nm. This biomimetic method suggests an analogy between the shape-forming processes of plants and their metallic models. Nanostruc- tured mesostructures of various metals （Ag, Pd, Ni）, alloys （PdNi, Pbln） and hybrid structures .（PdNi/Pb, PdNi/Pbln） were obtained. They can be of interest for fundamental research （self-assembly, morphogenesis） as well as for applications in nanotechnology （catalysis, nanoplasmonics, medicine, superhydrophobic surfaces）.

Large electromechanical strain at high temperatures of novel <001> textured BiFeGaO3-BaTiO3 based ceramics

BiFeGaO3-BaTiO3(BFG-BT)based ceramics with a large piezoelectric coefficient are potential high performance lead-free piezoelectric compounds.In this work,textured and random BFG-BT ceramics were realized by the solid state reaction method with and without BaTiO3(BT)templates.Textured ceramics were obtained by a reactive templated grain growth(RTGG)method leading to a high-temperature electromechanical strain of S=0.27%at 40 kV/cm and to an effective piezoelectric coefficient(d33*)up to 685 pm/V at 180℃.The easy movement of oriented domains enhanced the electromechanical strain under an applied electric field in textured sample(Lotgering factor f=66.3%).Structural investigations reveal that the proportion and degree of distortion of BFG-BT rhombohedral phase(R3c)reached its maximum in textured ceramics,resulting in large ferrodistortive displacements under electric fields.In addition,the dense nanodomains with low domain wall energies,inferred from the high-resolution transmission electron microscope(HR-TEM)observations,contribute to the extra displacement of the textured sample under an applied electric field.In textured ceramics,the remnant polarization was stable(about 17μC/cm2)from room temperature to 180℃,contributing to the stable ferroelectric property at high temperatures.Through the introduction of BT templates,high-density nanodomains were formed and the Burns temperature was enhanced in textured ceramics.The electromechanical strain,polarization and dielectric behavior were correlated to the textured or random forms of the BFG-BT based ceramics.

[001]-texturing of(K,Na)NbO_(3)-based piezoceramics with a pseudocubic structure and their application to piezoelectric devices

0.96(K_(0.5)Na_(0.5-z)Li_(z))(Nb_(0.92)Sb_(0.08))O_(3)-0.04(Ca_(0.5)Sr_(0.5))ZrO_(3)[(KN_(0.5-z)L_(z))NS-CSZ]piezoceramics(0≤z≤0.04)were aligned in the[001]orientation using 3%(in mole)NaNbO_(3)templates with a large Lotgering factor(>97%).Their crystal structures transformed from the orthorhombic-pseudocubic(O-P)structure to the orthorhombic-tetragonal-pseudocubic(O-T-P)structure with an increasing z.The P structure was interpreted as a rhombohedral R3m structure.The piezoelectricity of the compositions increased after[001]-texturing,and the enhancement was proportional to the O phase quantity.The composition(z=0.03)exhibited the highest piezoelectric constant(d_(33);670 pC/N)and electromechanical coupling factor(k_(p);0.56).Piezoelectric energy harvesters were produced using the untextured and textured samples(z=0.03).The textured harvester delivered a large power density of 26.6 mW/mm^(3),which was larger than that of the untextured harvester owing to the enhanced kp and d_(33)×g_(33) of the textured piezoceramic.A multilayer actuator was produced using the textured sample(z=0.03),and it exhibited a large acceleration(44.2 G)and displacement(±3,730 mm)at±25 V.Therefore,the[001]-textured(KN_(0.47)L_(0.03))NS-CSZ piezoceramic is suitable for piezoelectric energy harvesters and actuators.