This PDF file contains the front matter associated with SPIE Proceedings Volume 7267, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

The effect of microwave heating with a frequency of 2.45 GHz on the low-temperature crystallization of Pb(Zr_xTi_1-x)O₃ (PZT) films was investigated. PZT thin films were coated on Pt/Ti/SiO₂/Si substrates by the sol-gel method and then crystallized by single-mode 2.45 GHz microwave irradiation in the magnetic field. The elevated temperature generated by microwave heating used to obtain the perovskite phase was only 450°C, which is significantly lower than that of conventional thermal processing. The PZT films crystallized by microwave heating at 450°C showed similar ferroelectric properties to those of the films crystallized by conventional thermal processing at 600°C. The average remanent polarization and coercive field of the PZT films are approximately 21 µC/cm² and 90 kV/cm, respectively. It is clear that single-mode microwave irradiation in the magnetic field is effective for obtaining perovskite PZT thin films at low temperatures.

This paper details investigations in two multiferroic materials, Co-doped BaTiO₃ (BTO) and pure BiFeO₃ (BFO). The Co doping in BTO was to induce a magnetic moment into the ferroelectric BTO crystal while BFO is known to be ferroelectric and magnetic. Co-BTO was synthesized and studied in the bulk ceramic form while BFO was sputter deposited on to Si substrate and studied in the thin film form. The samples were heated in argon and air at specified temperatures and their magnetic properties were assessed. It was found that heating in O-poor, argon induced a significantly higher magnetic moment at saturation while the O-rich atmosphere did not. Subsequent investigations using XANES and XPS seem to indicate that the O-vacancy levels when heated in these atmospheres changed. Repeated heating in the two atmospheres alternatively confirmed the switching of magnetic behaviour indicating that this could be used as material whose saturation magnetization could be manipulated by prior heat treatment. This could also be a material to sense the O-level in a high temperature gaseous environment since it would be registered in its memory as the magnetic saturation moment.

Electromechanical impedance (EMI) technique using lead zirconate titanate (PZT) transducers has been increasingly applied to structural health monitoring (SHM) of aerospace, civil and mechanical structures. The PZT transducers are usually surface bonded to or embedded in a structure and subjected to actuation so as to interrogate the structure at the desired frequency range. The interrogation results in the electromechanical admittance (inverse of EMI) signatures which can be used to estimate the structural health or integrity according to the changes of the signatures. In the existing EMI method, the vibration of the structure caused by the external excitations has been considered only for one dimensional scenario. This paper develops a two dimensional EMI model to account for the effect of external excitation on the PZT admittance signature. An application is illustrated with modeling of a simply supported Kirchoff plate interrogated by a single surface-bonded PZT transducer. Numerical simulation is also carried out to verify the theoretical model. Finally, the effect of external excitation on PZT impedance signature is discussed.

Silane encapsulated magnetic iron oxide nanoparticles were synthesized through a sequential approach. The nanoparticles were synthesised via a coprecipitation method to form Fe₃O₄ particles with an average particle size of 8.3 ± 2.3nm. Iron oxide nanoparticles were then coated with 3-glycidoxypropyltrimethoxysilane (GPTMS) to form core-shell type particles. Coating was performed using a base catalysed sol-gel process involving the direct condensation of GPTMS onto the particle surface. Elemental composition and crystal structure of the uncoated nanoparticles were determined by XRD. The coated particles were characterised with infra-red spectroscopy and energy dispersive x-ray spectroscopy (EDX) to confirm the presence of silane on the particles. TEM analysis and Scherrer broadening analysis of XRD were used to determine particle size and morphology of both coated and uncoated particles.

The nanoparticles of noble metal have attracted enormous interest due to their high catalytic, optical, magnetic and antimicrobial properties. Controlled growth and stabilization of these nanoparticles are essential for their diverse applications. In this work, platinum, and silver nanoparticles are grown onto ordered non-fluoro ionomers and dendrimer for catalytic and antimicrobial applications. This paper thus provides insight on the utilization of dendrimer compartment or ionic domains of non-fluoro ionomers for stabilizing these nanoparticles. UV/vis and TEM results confirm the size and the size distribution of the formed particles. In both cases, ionic domains or the dendrimers result in the stabilization of the colloids. TEM images indicate that platinum nanoparticles grown on ordered non-fluoro ionomers results in highly dispersed particles of small size 2-3 nm, while in dendrimer 8-10 nm silver colloids are formed. All of the synthesized dendrimer based silver complexes are proved to be effective antimicrobial agents in vitro and the platinum nanoparticles exhibit specific electrochemical activities.

The use of polyethersulfone (PES), an excellent but highly hydrophobic thermoplastic, as a matrix material for ionexchange membranes was investigated. To make PES ion-exchangeable, sulfonate groups were introduced to the polymer chains by sulfonation reaction with chlorosulfonic acid. The degree of sulfonation of sPES was estimated to be 21%. Preliminary experiments investigated the effect of polyethylene glycol (PEG) and Pluronic F127 as fillers to improve the hydrophilicity of the membranes. Moreover, a lab scale electrodialysis cell has been designed and set up to evaluate the performance of these novel membranes compared to the benchmark of commercial membranes. The results show promising properties of ion-exchange capacity, water uptake, conductivity and hydophilicity from blended membranes, comparable to commercial membranes, though the performance of the prepared membranes did not exceed the commercial one. Further characterization of the transport properties of ion-exchange membranes need to be investigated to be able to understand the effects of the fillers on the performance of the membranes in ED application.

In this paper, the effect of driving frequency on the actuation characteristics of ionic polymer-metal composites (IPMCs) is studied. The charge motion within the polyelectrolyte membrane under a dynamic electric potential is first formulated and investigated. Subsequently, the dynamic ion-ion interactions within the polyelectrolyte membrane clusters are studied. By analyzing the volumetric changes of the membrane clusters due to the electric field induced stresses and the elastic stresses in the backbones of the membrane, the bending moment expression due to the applied electric potential is obtained. By using this bending moment expression, the vibrations of an IPMC cantilevered beam subjected to electric potentials of different frequencies are calculated. The characteristics of the IPMCs behavior are discussed with comparison with experimental results.

Here, we report on a novel method of incorporating carbon nanotubes into a polymer matrix by using carbon nanotubes as a chain transfer agent (CTA) in Reversible Addition-Fragmentation chain Transfer (RAFT) polymerisations. The dithioester RAFT agents were covalently linked to multi-walled carbon nanotubes (MWCNTs) via a method, which involved the reaction of acyl halide MWCNTs with a magnesium chloride dithiopropanoate salt. Polystyrene (PSt) was subsequently grafted from the MWCNT surface via the core-first technique, which implies an outward growth of polymer chains from the core, using the R-group approach. The structure and morphology of the hybrid nanomaterials were investigated using FTIR, NMR, thrmogravimetric analysis (TGA) and atomic force microscopy (AFM) techniques. The results showed that the MWCNT chain transfer agent could be successfully used to mediate the growth of polystyrene polymer from the MWCNT surface via the living radical polymerisation approach.

Vertically aligning carbon nanotubes (VACNTs) onto 2D porous materials is advantageous for many conceivable electronic applications but also for investigating the unique water transport properties of CNTs and the molecular separation of molecules during fluid transport through their inner shell. Here we report a wet chemical technique to produce vertically-aligned single walled CNT arrays on porous silicon (pSi). The nanotubes were first acid treated to produce carboxylic acid functionalities on the single-walled CNT. The carboxy-functional nanotubes were then covalently immobilised on a pSi surface that had been either ozone treated or silanated with aminopropyl triethoxysilane (APTES). The VACNT surfaces were analysed with atomic force microscopy (AFM), confocal Raman spectral imaging and Fourier transform infrared (FTIR) spectroscopy. Dense arrays of VACNTs were observed with the obtained CNT orientation and surface coverage depending upon attachment method and attachment reaction time.

A cold-hibernated elastic memory (CHEM) structures technology is one of the most recent results of the quest for simple, reliable and low-cost self-deployable structures. The CHEM technology utilizes shape-memory polymers in open-cell foam structures or sandwich structures made of shape-memory-polymer foam cores and polymeric laminated-composite skins. It takes advantage of a polymer's shape memory and the corresponding internal elastic recovery forces to self-deploy a compacted structure. This paper describes these structures and their major advantages over other expandable and deployable structures presently used. Previous preliminary investigations and experiments have confirmed the feasibility of certain CHEM structures for space applications. Further improvements in CHEM technology and structure design widen potential space applications, including advanced solar sail structural concepts that are revealed and described in this paper.

Here we describe a new class of near superhydrophobic surfaces formed using fluorinated polyhedral oligosilsesquioxane (FluoroPOSS) urethane hybrids and porous silicon gradients (pSi). We demonstrate that the surface segregation behavior of the hydrophobic fluoro component can be controlled by the type and nature of chain extender of the urethane and resultant hydrophobic association via intra or intermolecular aggregation. The surface film formed exhibits near superhydrophobicity. This work has significant potential for applications in antifouling and self-cleaning coatings, biomedical devices, microfluidic systems and tribological surfaces.

The explosive abilities of porous silicon (pSi) provide an alternative to existing carbon based explosives, in addition to the possibilities of explosions on a nanoscale. Here, an investigation into these explosive properties is conducted, by introducing an oxidiser onto freshly etched pSi with varying pore sizes. Explosions are triggered via the application of an electric spark. Light output and spectral data are collected to characterize the exxplosion. The energy output is observed via Differential Scanning Calorimetry (DSC), and surface images collected using SEM and AFM.

Gradient surfaces have become invaluable tools for the high-throughput characterisation of biomolecule- and cellmaterial surface interactions as they allow for the screening and optimisation of surface parameters such as surface chemistry, topography and ligand density in a single experiment. Here, we have generated surface chemistry gradients on oxidised porous silicon (pSi) substrates using silane functionalisation. In these studies, pSi films with a pore size of 15- 30 nm and a layer thickness of around 1.7 ìm were utilised. The manufacture of gradient surface chemistries of silanes was performed using a simple dip coating method, whereby an increasing incubation time of the substrate in a solution of the silane led to increasing surface coverage of the silane. In this work, the hydrophobic n-octadecyldimethyl chlorosilane (ODCS) and pentafluorophenyldimethyl chlorosilane (PFPS) were used since they were expected to produce significant changes in wettability upon attachment. Chemical gradients were characterised using infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and sessile drop water contact angle measurements. In addition, the surface chemistry of the gradient was mapped using synchrotron IR microscopy. The ODCS gradient displayed sessile drop water contact angles ranging from 12° to 71°, confirming the successful formation of a gradient. IR microscopy and an XPS line scan confirmed the formation of a chemical gradient on the porous substrate. Furthermore, the chemical gradients produced can be used for the high-throughput in vitro screening of protein and cell-surface interactions, leading to the definition of surface chemistry on nanostructured silicon which will afford improved control of biointerfacial interactions.

The production of high quality optical devices based on porous silicon relies on having precise control over the refractive index and thickness of each porous silicon layer. Until now this has been achieved by pre-calibrating each growth system and making sure that parameters such as wafer doping, electrolyte concentration and temperature are kept constant with each fabrication. However low doped silicon required for IR based silicon photonics has significant non-uniformity in the index and growth rate during formation of the porous silicon. The solution we have developed is based on realtime in-situ monitoring of low-doped silicon during porous silicon growth. This process rapidly measures the optical interference between the porous silicon film and the backside silicon surface. The optical light source comes from six coarse-wavelength-division-multiplexed lasers, with rapid switching between wavelengths achieved using a microelectromechanical switch. The system permits rapid measurement (<1 sec) of the reflection spectra from all lasers, enabling real-time thickness and refractive index of each layer to be determined during growth. Our aim is to enable growth of high quality multi-layer films such as those required for Bragg Reflectors and high-Q Fabry-Perot microcavities. In this paper we briefly describe the instrument, the numerical models developed to gather the measurements, and show preliminary results gathered from this instrument during growth. The results show a good agreement with theoretical optical modelling, and also direct measurements of the porous silicon layers.

Atomic layer deposition (ALD) of SiO₂ onto nanoporous alumina (PA) membranes was investigated with the aim of adjusting the pore size and transport properties. PA membranes from commercial sources with a range of pore diameters (20 nm, 100 nm and 200 nm) were used and modified by atomic layer deposition using tris(tert-butoxy)silanol and water as the precursor couple. By adjusting the number of deposition cycles, the thickness of the conformal silica coating was controlled, reducing the effective pore diameter, and subsequently changing the transport properties of the PA membrane. Silica coated PA membranes with desired pore diameters from <5 nm to 100 nm were fabricated. In addition to the pore size, the transport properties and selectivity of fabricated silica coated PA membranes were controlled by chemical functionalisation using a silane with hydrophobic properties. Structural and chemical properties of modified membranes were studied by dynamic secondary ion mass spectrometry (DSIMS) and scanning electron microscopy (SEM). Spectrophotometric methods were used to evaluate the transport properties and selectivity of silica coated membranes by permeation studies of hydrophobic and hydrophilic organic molecules. The resultant silica/PA membranes with specific surface chemistry and controlled pore size are applicable for molecular separation, cell culture, bioreactors, biosensing and drug delivery.

The preparation of bilayer lipid membranes (BLMs) on solid surfaces is important for many studies probing various important biological phenomena including the cell barrier properties, ion-channels, biosensing, drug discovery and protein/ligand interactions. In this work we present new membrane platforms based on suspended BLMs on nanoporous anodic aluminium oxide (AAO) membranes. AAO membranes were prepared by electrochemical anodisation of aluminium foil in 0.3 M oxalic acid using a custom-built etching cell and applying voltage of 40 V, at 1^oC. AAO membranes with controlled diameter of pores from 30 - 40 nm (top of membrane) and 60 -70 nm (bottom of membrane) were fabricated. Pore dimensions have been confirmed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). AAO membranes were chemically functionalised with 3-aminopropyltriethoxysilane (APTES). Confirmation of the APTES attachment to the AAO membrane was achieved by means of infrared spectroscopy, X-ray photoelectron spectroscopy and contact angle measurements. The Fourier transform infrared (FTIR) spectra of functionalised membranes show several peaks from 2800 to 3000 cm^-1 which were assigned to symmetric and antisymmetric CH₂ bands. XPS data of the membrane showed a distinct increase in C1s (285 eV), N1s (402 eV) and Si2p (102 eV) peaks after silanisation. The water contact angle of the functionalised membrane was 80^o as compared to 20^o for the untreated membrane. The formation of BLMs comprising dioleoyl-phosphatidylserine (DOPS) on APTESmodified AAO membranes was carried using the vesicle spreading technique. AFM imaging and force spectroscopy was used to characterise the structural and nanomechanical properties of the suspended membrane. This technique also confirmed the stability of bilayers on the nanoporous alumina support for several days. Fabricated suspended BLMs on nanoporous AAO hold promise for the construction of biomimetic membrane architectures with embedded transmembrane proteins.

We demonstrate a holographic approach for fabrication of large-area photonic crystal (PhC) microstructures by applying a single top-cut hexagonal prism. It is designed and used to fabricate various two-dimensional PhC structures in photo-resist films and polymer-dispersed liquid crystals (PDLCs) systems. Interference patterns from the beams from the top-cut hexagonal prism are calculated. SPM observations of the PhCs provide the basis for measurement of the structural parameters. A good agreement is obtained for the measured PhCs structural parameters and calculated results. Far-field diffraction patterns and electrical switching characteristics of the holographic PDLCs systems are also investigated.

Rice straw, a waste agro-byproduct, which is abundant lignocellulose products from rice production, is a renewable energy sources in Vietnam. Bio-oil from rice straw is produced by thermal and catalytic pyrolysis using a fixed-bed reactor with heating rate 15^oC/min, nitrogen as sweeping gas with flow rate 120ml/min. Final temperature of the pyrolysis reaction is a significantly influence on product yield. The gas yield increased and the solid yield decreased as the pyrolysis temperature increasing from 400^oC to 600^oC. The bio-oil yield reached a maximum of 48.3 % at the pyrolysis temperature of 550^oC. Mesoporous Al-SBA-15 was used as acid catalyst in pyrolysis of rice straw. The obtained results showed that, in the presence of catalyst, yield of gas products increased, whereas liquid yield decreased and solid product remained the same as compared to the non-catalytic experiments. The effect of nanostructured catalysts on the product yields and distribution was investigated.

Materials assisting with the efforts of cell isolation are attractive for numerous biomedical applications including tissue engineering and cell therapy. Here, we have developed surface modification methods on microparticles for the purposes of advanced cell separation. Iron oxide nanoparticles were incorporated into 200 ìm polystyrene microparticles for separation of particle-bound cells from non-bound cells in suspension by means of a permanent magnet. The polystyrene microparticles were further encoded with fluorescent quantum dots (QD) as identification tags to distinguish between specific microparticles in a mixture. Cluster of differentiation (CD) antibodies were displayed on the surface of the microparticles through direct adsorption and various methods of covalent attachment. In addition, a protein A coating was used to orientate the antibodies on the microparticle surface and to maximise accessibility of the antigen-binding sites. Microparticles which carried CD antibodies via covalent attachment showed greater cell attachment over those modifications that were only adsorbed to the surface through weak electrostatic interactions. Greatest extent of cell attachment was observed on microparticles modified with protein A - CD antibody conjugates. B and T lymphocytes were successfully isolated from a mixed population using two types of microparticles displaying B and T cell specific CD antibodies, respectively. Our approach will find application in preparative cell separation from tissue isolates and for microcarrier-based cell expansion.

Diatoms are unicellular photosynthetic algae with enormous diversity of patterns in their silica structures at the nano- to micronscale. In this study, we present results, which support the hypothesis that silica nanoparticles are released into the diatom culture medium. The formation of an opalescent film by the self-assembly of silica nanoparticles produced in the growth medium of diatoms. This film was formed on the filter paper from the culture medium of a Coscinodiscus sp. culture. A numbers of diatoms with partially opened valves were observed on the film surface under light microscopy and SEM, which indicates that cell contents inside of diatoms had been released into the culture solution. AFM images of produced opalescent films show ordered arrays of silica nanoparticles with different diameters depending on the colors observed by light microscopy. The film forming silica nanoparticles are either released by the diatoms during reproduction or after cell death. This approach provides an environmentally friendly means for fabricating silica nanoparticles, decorative coatings and novel optical materials.

Carbon thin films can be prepared with properties that make them suitable for applications in electronics including heat sinks, electrical interconnects transistors and chemical sensors. In this work, we examine the microstructure and normalised through film electrical resistance of oriented and non-oriented carbon films deposited onto silicon substrates at room temperature using a Filtered Cathodic Vacuum Arc (FCVA). Electrical measurements have also been performed on carbon films which were lithographically patterned to produce test structures resembling vertical interconnects. Twopoint, through-film current-voltage measurements of NiCr/Carbon/Si structures showed that the electrical resistance of the carbon films could be varied by several orders of magnitude simply by selecting different substrate bias voltages. Importantly, carbon films composed of vertically aligned graphene sheets were found to provide low resistance, linear current-voltage characteristics, indicating the formation of Ohmic junctions at the NiCr and Si interfaces of the NiCr/Carbon/Si structure.

The paper presents a novel fiber optic microbend sensor with intelligent self-healing function, which is based upon the photocurable technology and the mode-coupling theory. In the research, a kind of photocurable material is developed and injected into the flexible hollow-center fiber embodying the sensitive optic fiber. According to the theory of fiber optic microbend sensors, the microbending mechanism causes part of the optical power to be radiated out of the fiber due to the mode-coupling. Especially when the damage of the sensitive optic fiber occurs due to the extremely small bending radius, the radiation power will increase rapidly. We use the radiation power as the curing light to initiate the photopolymerization of the photocurable material surrounding the sensitive optic fiber. The scale and speed of the photochemistry reaction mainly depend on the radiation power and the microbend degree. By this way, the photocurable material can repair the damaged area in real time according to the damaged state. This paper describes the design and performances of the intelligent self-healing fiber optic microbend sensor in detail. The experimental results reveal that the sensor has the excellent sensing property and can adjust its repairing ability according to the damaged degree automatically.

Fe containing SBA-15 mesoporous material was successfully prepared by direct synthesis and post-synthesis (atomic implantation) methods. The obtained Fe-SBA-15 samples were characterized by different techniques such as XRD, BET, TEM and UV-Vis. It showed that for both methods, Fe containing SBA-15 samples have highly ordered hexagonal nano-structure with large pore size. It revealed the existence of both Fe species: Fe-tetrahedral coordinated and Fe-highly dispersed species. However, higher portion of Fe-highly dispersed species in the samples prepared post-synthesis (atomic implantation) was found. The Fe-SBA-15 catalysts were tested in catalytic oxidation of phenol and red phenol. The results indicated that both Fe-incorporated and Fe-highly dispersed species were active sites. However, the latter exhibited higher activity compared to the former ones.

Poly(dimethylsiloxane) (PDMS) is a popular material for microfluidic devices due to its relatively low cost, ease of fabrication, oxygen permeability and optical transmission characteristics. However, its highly hydrophobic surface is still the main factor limiting its wide application, in particular as a material for biointerfaces. A simple and rapid method to form a relatively stable hydrophilised PDMS surface is reported in this paper. The PDMS surface was treated with pure undecylenic acid (UDA) for 10 min, 1 h and 1 day at 80 °C in a sealed container. The effects of the surface modification were investigated using water contact angle (WCA) measurements, Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR), and streaming zeta-potential analysis. The water contact angle of 1 day UDAmodified PDMS was found to decrease from that of native PDMS (110 °) to 75 °, demonstrating an increase in wettability of the surface. A distinctive peak at 1715 cm-1 in the FTIR-ATR spectra after UDA treatment was representative of carboxylation of the PDMS surface. The measured zeta-potential (ζ) at pH 4 changed from -27 mV for pure PDMS to -19 mV after UDA treatment. In order to confirm carboxylation of the surface visually, Lucifer Yellow CH fluorescence dye was reacted via a condensation reaction to the 1 day UDA modified PDMS surface. Fluorescent microscopy showed Lucifer Yellow CH fluorescence on the carboxylated surface, but not on the pure PDMS surface. Stability experiments were also performed showing that 1 day modified UDA samples were stable in both MilliQ water at 50 °C for 17 h, and in a desiccator at room temperature for 19.5 h.

Nanocomposites of high density polyethylene (HDPE) reinforced with hybrid fillers of polyaniline coated multiwalled carbon nanotube (MWNT), and carbon black (CB) were developed aiming at enhancing the electrical conductivity of the composites. The electrical properties such as volume resistivity, impedance, and conductance have been measured as a function of filler volume concentration (%), frequency and voltage. The electrical property such as volume resistivity depends on the concentration of fillers. This is due to the formation of a continuous conducting network throughout the polymer matrix with increase in the conducting filler. This kind of variation is referred as Maxwell-Wagner effect. The resistance of the prepared PANI/c-MWNT/CB/HDPE nanocomposites is found to be ohmic. It was shown that adding CB in PANI/c-MWCNTs composites can enhance the electrical properties of the nanocomposites: a low percolation threshold was achieved with 0.25 wt% CNTs and 20 wt% of CB/HDPE. CB enhanced the ductility of the nanocomposites, confirming the synergic effect of CB as effective multi-functional filler.