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pH sensitive graphene-polymer composites have been prepared by the modification of graphene basal planes with pyrene-terminated poly(2-N,N'-(dimethyl amino ethyl acrylate) (PDMAEA) and poly(acrylic acid) (PAA) via pi-pi stacking. The pyrene-terminal PDMAEA and PAA were synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization with a pyrene-functional RAFT agent. The graphene-polymer composites were found to demonstrate phase transfer behavior between aqueous and organic media at different pH values. Atomic force microscopy (AFM) analysis revealed that the thicknesses of the graphene-polymer sheets were approximately 3.0 nm when prepared using PDMAEA (M(n): 6800 and PDI: 1.12). The surface coverage of polymer chains on the graphene basal plane was calculated to be 5.3 x 10(-11) mol cm(-2) for PDMAEA and 1.3 x 10(-10) mol cm(-2) for PAA. The graphene-polymer composites were successfully characterized using X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared (ATR-IR) spectroscopy, and thermogravimetric analysis (TGA). Self-assembly of the two oppositely charged graphene-polymer composites afforded layer-by-layer (LbL) structures as evidenced by high-resolution scanning electron microscopy (SEM) and quartz crystal microbalance (QCM) measurements.

A synthetic protocol for the preparation of hetero-biofunctional protein-polymer conjugates is described. A chain transfer agent, SS-bis (alpha,alpha'-dimethyl-alpha ''-acetic acid) trithiocarbonate was functionalized with alpha,omega-pyridyl disulfide (PDS) groups, Subsequently, one of the PDS groups was covalently attached to bovine serum albumin (BSA) at the specific free thiol group on the cysteine residue through a disulfide linkage. The second PDS group remained intact, as it was found to be inaccessible to further BSA functionalization. The BSA-macro-reversible addition-fragmentation chain transfer (RAFT) agent was then used to prepare BSA-polymer conjugates via in situ polymerization of oligo (ethyleneglycol) acrylate and N-(2-hydroxypropyl) methacrylamide using an ambient temperature initiator, 4,4'-azobis [2,9-imidazolin-2-ethyl)propane] dihydrochloride in an aqueous medium. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that the in situ polymerization occurred at the protein surface where the RAFT agent was attached and the molecular weights of the BSA-polymer conjugates were found to increase concomitantly with monomer conversion and polymerization time. After polymerization the remaining terminal PDS groups were then utilized to attach thiocholesterol and a flurophore, rhodamine B to the protein-polymer conjugates via disulfide coupling. UV-Vis and fluorescence analyses revealed that similar to 80% of the protein conjugates were found to retain integral PDS end groups for further attachment to free thiol-tethered precursors. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1399-1405, 2010

Concavo-convex micelles with controllable sizes and nanostructures are prepared via self-assembling polymer-enzyme (e.g., shellac enzyme) conjugates with heterogeneous polymer chains, which exhibit higher enzyme stability (300%) and bioactivity (760%) comparing with the well-defined ones. The applied amphiphilic and negatively charged copolymer, poly (methyl methacrylate)-block-poly (sodium p-styrene sulfonate), is synthesized via reversible addition-fragmentation chain transfer polymerization to modify shellac enzyme and immobilize the enzyme bioactivity inducer by covalent conjugation and electrostatic attraction, respectively. The degradation test of catechol confirms the application potential of as-prepared micelles as an efficient and economical decontaminant.

The design and utility of polymer-stabilized iron-oxide nanoparticles for nanomedicine applications

Porous metal microneedles were fabricated by an incorporated process of cutting and wet etching. Each microneedle is comprised of many connecting microholes that can deliver drugs into organisms conveniently and efficiently. The microneedle height is larger than 400 μm, the pitch distance is about 800 μm and the microholes in each microneedle are about 20 μm in diameter. In force testing, the microneedles could resist large shear forces and pierce into skins easily; in the in vivo experiment, the insulin was efficiently injected into rats by a patch of the microneedles. The testing and the experiment demonstrated that the microneedles could deliver drugs into organisms to treat diseases without fracture.

Elastic graphene aerogels are lightweight and offer excellent and electrical performance, expanding their significance in many applications. Recently, elastic graphene aerogels have been fabricated via various methods. However, for most reported elastic graphene aerogels, the fabrication processes are complicated and the applications are usually limited by the brittle mechanical properties. Thus, it still remains a challenge to explore facile processes for the fabrication of graphene aerogels with low density and high compressibility. Herein, arbitrary-shaped, superelastic, and durable graphene aerogels are fabricated using melamine foam as sacrificial skeleton. The resulting graphene aerogels possess high elasticity under compressive stress of 0.556 MPa and compressive strain of 95%. Thanks to the superelasticity, high strength, excellent flexibility, outstanding thermal stability, and good electrical conductivity of graphene aerogels, they can be applied in sorbents and pressure/strain sensors. The as-assembled graphene aerogels can adsorb various organic solvents at 176-513 g g(-1) depending on the solvent type and density. Moreover, both the squeezing and combustion methods can be adopted for reusing the graphene aerogels. Finally, the graphene aerogels exhibit stable and sensitive current responses, making them the ideal candidates for applications as multifunctional pressure/strain sensors such as wearable devices.

Thermosensitive graphene-polymer composites have been prepared by attaching poly(N-isopropylacrylamide) (PNIPAAm) onto the basal plane of graphene sheets via pi-pi stacking. Pyrene-terminated PNIPAAm was synthesized using reversible addition fragmentation chain transfer (RAFT) polymerization via a pyrene-functional RAFT agent. Aqueous solutions of the graphene-polymer composites were stable and thermosensitive. The lower critical solution temperature (LCST) of pyrene-terminated PNIPAAm was measured to be 33 degrees C. When the pyrene-functional polymer was attached to graphene the resultant composites were also thermosensitive in aqueous solutions exhibiting a reversible suspension behavior at 24 degrees C. Atomic force microscopy (AFM) analysis revealed that the thickness Of a graphene-PNIPAAm (M-n: 10,000 and PDI: 1.1) sheet was similar to 5.0 nm. The surface coverage of polymer chains on the graphene basal plane was calculated to be 7.2 x 10 (11) mol cm(-2). The graphene-PNIPAAm composite material was successfully characterized using X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared (ATR-IR) spectroscopy, and thermogravimetric analysis (TGA). (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 425-433, 2010

Six-armed biodegradable star polymers made from polystyrene (polySt), poly(polyethylene glycol) acrylate (polyPEG-A) and the block copolymer, polySt-b-polyPEG-A were synthesized using a 'core-first' methodology via RAFT polymerization. Disulfide linkages between the core and the arms conferred biodegradability on the stars. The star architectures were found to degrade rapidly on treatment with DL-dithiothreitol (DTT) and degrade more slowly in the presence of glutathione (GSH), the most abundant intracellular thiol tethered peptide. These star polymers were well characterized using gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), electrospray ionization mass spectroscopy (ESI-MS) and dynamic light scattering (DLS). (C) 2009 Elsevier Ltd. All rights reserved.

A straightforward synthetic approach to the preparation of disulfide linked hyperbranched polymers with peripheral pyridyl disulfide functionalities is described. The hyperbranched polymers were ob...

Three-armed biodegradable star polymers made from polystyrene (polySt) and poly (polyethylene glycol) acrylate (polyPEG-A) were synthesized via a "core first" methodology using a trifunctional RAFT agent, created by attaching RAFT agents to a core via their R-groups. The resultant three-armed polymeric structures were well-defined, with polydispersity indices less than 1.2. Upon aminolysis and further reaction with dithiodipyridine (DTDP), these three-armed polymers could be tailored with sulfhydryl and pyridyldisulfide (PDS) end functionalities, available for further reaction with any free-sulfhydryl group containing precursors to form disulfide linkages. Nuclear magnetic resonance (NMR) confirmed that more than 98% of the polymer arms retained integral trithiocarbonate active sites after polymerization. Intradisulfide linkages between the core and the arms conferred biodegradability on the star architectures. Subsequently, the arm-termini were attached to cholesterol also via disulfide linkages. The cholesterol terminated arms were then used to form supramolecular structures via inclusion complex formation with beta-cyclodextrin (beta-CD). The star architectures were found to degrade rapidly on treatment with DL-dithiothereitol (DTT). The star polymers and supramolecular structures were characterized using gel permation chromatography (GPC), static light scattering (SLS), 2D NMR, and fluorescence spectroscopy.

This paper presents a micro electromagnetic energy harvester which can convert low level vibration energy to electrical power. It mainly consists of an electroplated copper planar spring, a permanent magnet and a copper planar coil with high aspect ratio. Mechanical simulation shows that the natural frequency of the magnet-spring system is 94.5 Hz. The resonant vibration amplitude of the magnet is 259.1 μm when the input vibration amplitude is 14 μm and the magnet-spring system is at resonance. Electromagnetic simulation shows that the linewidth and the turns of the coil influence the induced voltage greatly. The optimized electromagnetic vibration energy harvester can generate 0.7 μW of maximal output power with peak–peak voltage of 42.6 mV in an input vibration frequency of 94.5 Hz and input acceleration of 4.94 m/s2 (this vibration is a kind of low level ambient vibration). A prototype (not optimized) has been fabricated using MEMS micromachining technology. The testing results show that the prototype can generate induced voltage (peak–peak) of 18 mV and output power of 0.61 μW for 14.9 m/s2 external acceleration at its resonant frequency of 55 Hz (this vibration is not in a low ambient vibration level).

Pyridyldisulfide (PDS) functionalized telechelic polymers of oligo(ethyleneglycol) acrylate (PEG-A) and their amphipbilic triblock copolymers with styrene (St) were synthesized directly by reversible addition-fragmentation chain transfer (RAFT) polymerization using a new bifunctional RAFT agent, S,S-bis[alpha,alpha'-dimethyl-alpha '' -(2-pyridyl disulfide) ethyl acetatel trithiocarbonate (BDPET). The homopolymerization of PEG-A was found to be well controlled using BDPET (PDI < 1.2). The ABA triblock copolymers poly(PEG-A)-b-poly(St)-b-poly(PEG-A) with narrow molecular weight distribution (PDI < 1.25) were synthesized using poly(PEG-A) as a macro-RAFT agent. UV-vis spectroscopic analysis revealed that 85 mol % of poly(PEG-A) and 78 mol % of poly(PEG-A)-b-poly(St)-b-poly(PEG-A) retained PDS end group functionality. Micelles were observed to form from poly(PEG-A)-b-poly(St)-b-poly(PEG-A). The presence of PDS groups within the micelle corona was evidenced by UV-vis spectroscopy and fluorescence spectroscopy. The PDS groups within the corona were then used to functionalize the micelles with a thiol group bearing model peptide, reduced glutathione, and a thiol modified fluorophore, rhodamine B, under mild reaction conditions. UV-vis and fluorescence spectrocopies revealed that approximately 80% PDS groups from the amphiphilic copolymer were tethered within the micelle coronas and accessible to glutathione and fluorophore attachment. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 899-912, 2009

A novel micro CRLH (composite right/left-handed) wide band filter based on Left handed material (LHM) theory was designed and fabricated. As a promising design, the length of the main part is only 1/20 compared to the working wavelength. It can be used to eliminate the noise in RF interconnect and other area. The phase shift in LHM is negative. This characteristic can decrease the phase delay. And also, the absolute value of phase constant will increase when frequency decrease at the left handed band (LH-band), which contribute to minimize the design. The other advantage of the LHM is that the phase constant will changed to the opposite direction, when the wavelength changed with the working frequency. This provides a negative feedback to the electric length, so the left handed region has a wider band width. Measurements results show that relative bandwidth (3dB) of 8 cells is 71.42%. The relative bandwidth (3dB) of 4 cells is 58.46%.

Two RAFT agents, suitable for inducing living radical polymerization in water, have been synthesized. Both RAFT agents were shown to be effective over the temperature range 25-70 degrees C. One RAFT agent was functionalized. with a pyridyl disulfide group. RAFT efficacy was demonstrated for the polymerizations of N-isopropyl acrylamide (NIPAAM) and poly(ethylene oxide)-acrylate (PEG-A) in both water and acetonitrile. The kinetic data indicates that the pyridyl disulfide functionality is largely benign in free radical polymerizations, remaining intact for subsequent reaction with thiol groups. This result was confirmed by studying conventional radical polymerizations in the presence of hydroxyethyl pyridyl disulfide. The utility of the pyridyl disulfide functionality at the terminus of the polymers was demonstrated by synthesizing polymer-BSA conjugates. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7207-7224, 2008

Direct synthesis of well-defined heterotelechelic polymers having functional groups allowing the chemoselective bioconjugations would be desirable to enhance the versatility of polymers for bioconjugations and bio-related applications. Considering this, well-defined α-azide, ω-dithiopyridine polymers were synthesized in one step via the reversible addition−fragmentation chain transfer (RAFT) polymerization. The telechelic functionality (i.e., mole ratio of the ω-dithiopyridine to the α-azide end group) of polymers was above 0.90, indicating the efficient generation of well-defined heterotelechelic polymers. The heterotelechelic functionality for chemoselective bioconjugations was tested by reacting α-azide, ω-dithiopyridine poly(NIPAAm) with model biomolecules, i.e., biotin/avidin, glutathione, and bovine serum albumin, via click and thiol−disulfide exchange chemistries. Near-stoichiometric conjugation with biomolecules indicated high functionality of the polymer end groups.

Piezoelectric power generator made by microelectromechanical system (MEMS) technology can scavenge power from low-level ambient vibration sources. The developed MEMS power generators are featured with fixed/narrow operation frequency and power output in microwatt level, whereas, the frequency of ambient vibration is floating in some range, and power output is insufficient. In this paper, a power generator array based on thick-film piezoelectric cantilevers is investigated to improve frequency flexibility and power output. Piezoelectric cantilevers array has been designed and fabricated. The cantilevers array can be tuned to the frequency and expanded the excited frequency bandwidth in ambient low frequency vibration. Serial connection among cantilevers of the array is investigated. The prototype generator has a measured performance of [email protected] effective electrical power and 3.93 DC output voltage to resistance load. This device is promising to support networks of ultra-low-power, peer-to-peer, wireless nodes.

Nanoimprint lithography (NIL), as a low-cost and mass production technique, has played an important role in micro/nano fabrication. However, the sticking problem between the stamp and resist blocks its further application. In order to modify the contact surface, a molecular dynamics (MD) method was used to choose the proper material to coat on the surface of the stamp. According to the MD analysis, CF2 was found to be a good choice for this purpose. It was applied to the nanoimprint stamp by using the gases in reactive ion etching (RIE). A self-assembly monolayer (SAM) layer was also used in the experiment to release the contact surface energy. Both dry and wet methods were demonstrated as excellent anti-sticking approaches by measuring the contact angles and calculating the surface energy. Both the stamps after anti-sticking treatment can be used more times than the untreated stamps.

In this report, a novel chemical synthesis of polyaniline/gold nanocomposite is explored using ionic liquid (IL) 1-Butyl-3-methylimidazolium hexafluorophosphate. The direct chemical synthesis of polyaniline/gold nanocomposite was initiated via the spontaneous oxidation of aniline by AuCl4 −in IL. A nearly uniform dispersion of polyaniline/Au particles with a diameter of 450 ± 80 nm was produced by this method, which indicates that this method is more suitable for controlling particle dimensions. It was also found that the electrical conductivity of the polyaniline/gold nanocomposite was more than 100 times higher than that of the pure polyaniline nanoparticles. The polyaniline/gold nanocomposite displays superior function in the biocatalytic activation of microperoxidase-11 because of the high surface area of the assembly and the enhanced charge transport properties of the composite material. We also report the possible application of polyaniline/gold nanocomposite as a H2O2biosensor.

The influence of both nanotube orientation and length on the electrochemical properties of electrodes modified with single-walled carbon nanotubes was investigated. Gold electrodes were modified with either randomly dispersed or vertically aligned nanotubes to which ferrocenemethylamine was attached. Electron transfer kinetics were found to depend strongly on the orientation of the nanotube, with electron transfer between the gold electrode and the ferrocene moiety being 40 times slower through randomly dispersed nanotubes than through vertically aligned nanotubes. The difference is hypothesized to be due to electron transfer being more direct through a single tube than that with electrodes modified with randomly dispersed nanotubes. With the vertically aligned nanotubes the rate constant for electron transfer varied inversely with the mean length of the nanotubes. The results indicate there is an advantage in using aligned carbon nanotube arrays over randomly dispersed nanotubes for achieving efficient electron transfer to bound redox active species such as in the case of bioelectronic or photovoltaic devices. Keywords: Single-walled carbon nanotubes, Electron transfer, Ferrocene, Self-assembled monolayers, Nanostructured electrodes

Suspensions of mesoscale gold half-shells of controlled size were produced by microsphere-templated vapour deposition and their optical properties were studied. The transmission spectra of the particles exhibited an extinction peak that could be tuned from 530 to over 2000 nm by variation of the diameter of the template used. In this respect the optical properties of these reduced-symmetry particles are similar to those of full nanoshells, however they may be more convenient to prepare. © 2007 Elsevier B.V. All rights reserved.

(Figure Presented) A good place for rafting: Bovine serum albumin (BSA) was site-specifically modified with a reversible addition fragmentation chain transfer (RAFT) agent and used in γ-radiation-initiated polymerization of oligo(ethylene glycol) acrylate. Well-defined polymer chains were formed at the RAFT agent conjugation site of BSA leading to the generation of BSA-polymer conjugates in situ. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.

A trithiocarbonate RAFT agent was modified with a pyridyl disulfide group and used in the direct synthesis of endgroup pyridyl disulfide-functionalized homo- and amphiphilic 'block copolymers of oligo (ethylene glycol) acrylate (PEG-A) and butyl acrylate (BA). Both the homoand copolymerizations were found to be well controlled via the RAFT mechanism. The NMR analysis indicated that both the homopolymers of PEG-A and the amphiphilic diblock copolymers of PEG-A and BA possessed pyridyl disulfide terminal groups. A UV-Vis absorption test revealed that the pyridyl disulficle endgroup of the polymer could be efficiently used to couple thiol-bearing molecules to the polymer without the need for any post-polymerization modification. This communication presents the first efficient direct synthesis of thiol-reactive endgroup-functionalized well-defined polymers via the RAFT technique.

A novel method for fabrication of multi-layer microstructures of microelectro-mechanical system (MEMS) devices is described. This technique, which combines bulk silicon micromachining technique and UV-LIGA technique can overcome some shape limitations of single technique on complex microstructures. To demonstrate this combination, the SU-8 microstructure fabricated in the etched silicon grooves is presented. In this fabrication process, a SU-8 removal method by fuming sulfuric acid was introduced and a novel type of plastics PETG was tried in microhot embossing process. The proposed fabrication process can be applied to fabricating a high-aspect-ratio microstructure for a large displacement actuator and precision sensors. Moreover, this combined process enables the fabrication of more complex structures, which cannot be fabricated by bulk micromachining or UV-LIGA alone.

Carbon nanomaterials, including fullerene, carbon nanotubes, graphene and graphene oxide have raised tremendous attentions for their biomedical applications. Their high surface area, low toxicity and unique optical property make them ideal candidates for drug delivery and photo-thermal therapeutics. Carbon nanomaterials can be engineered into multifunctional drug delivery platforms through sophisticated chemistry approaches. The advanced design of carbon nanomaterials make them feasible to target diseased tissues, to deliver high doses of drugs and enable real time imaging in vivo. Numerous preclinical studies of carbon nanomaterials (e.g. carbon nanotube) have showed improved therapeutics such as cancer therapy as compare to traditional therapy. In addition, with the growing concerns of nanotoxicity to environment and human health, systematic toxicological studies of carbon nanomaterials have been conducted in the last decades. These studies not only elucidated paradigms and mechanisms of carbon nanomaterials-associated nanotoxicity, but also provided benchmarks to produce non-toxic carbon nanomaterials. In this chapter, we reviewed recent research progress of the toxicological and pharmacological studies of carbon nanomaterials aiming to highlight their potential biomedical applications in the future.

The neural interface is a key component in wireless brain–computer prostheses. In this study, we demonstrate that a unique three-dimensional (3D) microneedle electrode on a flexible mesh substrate, which can be fabricated without complicated micromachining techniques, is conformal to the tissues with minimal invasiveness. Furthermore, we demonstrate that it can be applied to different functional layers in the nervous system without length limitation. The microneedle electrode is fabricated using drawing lithography technology from biocompatible materials. In this approach, the profile of a 3D microneedle electrode array is determined by the design of a two-dimensional (2D) pattern on the mask, which can be used to access different functional layers in different locations of the brain. Due to the sufficient stiffness of the electrode and the excellent flexibility of the mesh substrate, the electrode can penetrate into the tissue with its bottom layer fully conformal to the curved brain surface. Then, the exposed contact at the end of the microneedle electrode can successfully acquire neural signals from the brain.

We describe an alternative electrochemical technique to monitor covalent bond formation in real-time using nanoparticle-electrode collisions. The method is based on recognising the redox current when MP-11 functionalised chemical reduced graphene oxide (rGO) nanosheets collide with Lomant's reagent modified gold microelectrode. This facile and highly sensitive monitoring method can be useful for investigating the fundamental of single-molecule reactions.

We demonstrate that mixed-phase anatase-TiO2(B) nanoparticles can provide an interesting interphase interface with atomic-level contact for achieving more efficient Li ion storage with high capacity and cycle life. A novel lithium storage mode - "interfacial charge storage in allomorphs" (ICSA) - plays an important role in enhancing Li ion storage.

A portable lab-on-a-chip methodology to generate ionic liquid-functionalized carbon nanodots (CNDs) was developed via electrochemical oxidation of screen printed carbon electrodes. The CNDs can be successfully applied for efficient cell imaging and solid-state electrochemiluminescence sensor fabrication on the paper-based chips.

This paper presents a transdermal power transfer device for the application of implantable devices or systems. The device mainly consists of plug and socket. The power transfer process can be started after inserting the plug into the socket with an applied potential on the plug. In order to improve the maneuverability and reliability of device during power transfer process, the metal net with mesh structure were added as a part of the socket to serve as intermediate electrical connection layer. The socket was encapsulated by polydimethylsiloxane (PDMS) with good biocompatibility and flexibility. Two stainless steel hollow needles placed in the same plane acted as the insertion part of the needle plug, and Parylene C thin films were deposited on needles to serve as insulation layers. At last, the properties of the transdermal power transfer device were tested. The average contact resistance between needle and metal mesh was 0.454 Ω after 50 random insertions, which showed good electrical connection. After NiMH (nickel-metal hydride) batteries were recharged for 10 min with current up to 200 mA, the caused resistive heat was less than 0.6 °C, which also demonstrated the low charging temperature and was suitable for charging implantable devices.

Iridium oxide has been widely used in neural recording and stimulation due to its good stability and large charge storage capacity (CSC). In general, the iridium oxide film used in the electrophysiological application can be grouped into three principal classifications: sputtering iridium oxide film (SIROF), activated iridium oxide film (AIROF) and electrodeposited iridium oxide film (EIROF). Although these kinds of iridium oxide all can remarkably reduce the impedance and increase the CSC of the microelectrode, they also exhibit markedly differences in electrochemical performances. After activation, the CSC of EIROF is 68.20 mC/cm(2), which is 88.7 % larger than that of the SIROF and 67.6 % larger than that of the AIROF. The impedance at 1 kHz of the three kinds of iridium oxide microelectrode is around 4000 ohm, it is acceptable for the neural interface application. The phase at 1 kHz of the AIROF microelectrode is the largest which is -6.1 degree, about 22.6 % of the SIROF and 44.5 % of the EIROF.

This paper develops a novel and simple process device based on an atmospheric pressure air microplasma jet for the selective etching of parylene-C film. In order to realize the selective etching, a quartz glass microtube (100 µm, inner diameter) is employed to generate the air microplasma jet. Experimental results demonstrated Micro-holes, micro-trenches on parylene-C film were successfully fabricated by the air microplasma jet without causing any heat damage to films and using any masks, and the etching rate reached 5.14µm/min. Due to its operating at ambient conditions, this process device can be easily integrated with roll-to-roll systems for large-scale manufacturing of flexible electronic devices in the future.

This paper studied a triboelectric and piezoelectric coupling nanogenerator based on MEMS technology. The electrospinning PVDF-TrFE nanofibers are not only used as a piezoelectric functional layer, but also as a friction layer of triboelectric generator. The other flexible friction layer is realized by PDMS films with doped multiwall carbon nanotubes (MWCNT). The sandwich-shaped nanogenerator's triboelectric output peak voltage, piezoelectric output peak voltage, triboelectric energy power, piezoelectric energy power, triboelectric energy volume power density and piezoelectric energy volume power density are 5V, 30V, 98.66µW, 9.74µW, 1.98mW/cm3 and 0.689mW/cm3 under the pressure force of 5 N, respectively. This device has some advantages such as flexibility, thickness controllability, double coupling mechanisms.

A MEMS-based energy harvesting device, micro piezoelectric power generator, is designed to convert ambient vibration energy to electrical power via piezoelectric effect. In this work, the generator structure of composite cantilever with nickel metal mass is devised. Micro-electronic-mechanical systems (MEMS) related techniques such as sol-gel, RIE dry etching, wet chemical etching, UV-LIGA are developed to fabricate the device and then its performance is measured on vibration testing setup. The investigation shows that the designed device is expected to resonantly operate in low-frequency environmental vibration through tailoring the structure dimension. Under the resonant operation with frequency of about 608Hz, a first prototype of the generator result in about 0.89V AC peak-peak voltage output to overcome germanium diode rectifier toward energy storage, and its power output is in microwatt level of 2.16@mW.

We developed a disk-type non-contact ultrasonic motor based on B22 vibration mode. The rotors of SU-8 photoresist are fabricated by the UV-LIGA process to control their shapes and thicknesses. So the structures of them are optimized by the experiments. It is found that the revolution speed of disk-type non-contact ultrasonic motor not only depends on the vibration amplitude of the stator, but also the weight and construction of the rotors. The maximum revolution speed of the optimal rotor is 3569 rpm at the input voltage of 20 V and the driving frequency of 45.6 kHz. The exciting principle of traveling wave is presented with theoretical equations. The electric signals applied to the piezoelectric ceramic are designed by the principle. The natural frequency and corresponding vibration mode are calculated and analyzed using finite element method. It is shown that experimental results are in good agreement with simulation, which verifies the effectiveness of the finite element model. Moreover, the levitation distance between the stator and rotor is measured by a CCD laser displacement transducer.

An electrode construct was fabricated in which a self-assembled monolayer containing a novel norbornylogous bridge was covalently attached to flavin adenine dinucleotide (FAD), the redox active centre of several oxidase enzymes. The electrochemistry of the construct was investigated before and after the reconstitution of glucose oxidase around the surface bound FAD. Rapid rates of electron transfer were observed both before and after the reconstitution of biocatalytically active enzyme. However, no biocatalytic activity was observed under anaerobic conditions suggesting the a lack of enzyme turnover through direct electron transfer. It is proposed that a decrease in the electronic coupling between the redox active FAD and the electrode following reconstitution of the glucose oxidase – a probable consequence of the FAD being immersed in a protein environment – was responsible for the inability of the enzyme to be turned over under anaerobic conditions.

Conventional three-dimensional (3D) microstructures such as arcs or spiralities are generally fabricated using some complicated methods like LIGA or two-photon lithography. In this paper, a new approach of fabricating 3D microstructures is provided. The process is based on UV-LIGA technology yet including a novel reformation method in the post bake procedure. The fabrication process started with coating SU-8 as thick as 500 microns on the silicon substrate, and then it was followed by an exposure with patterned mask under UV light. Subsequently, a force on the exposed SU-8 photo resist was applied in the post-bake process. By adjusting the amount of force, the way in which the force was placed and the exposure dose, we directly fabricated some complicated three-dimensional structures on the SU-8 photo resist after development of the SU-8. We call this microfabrication method as Force-LIGA (F-LIGA). Firstly, orthogonal experiment method conducted to optimize the hot-press process is presented, and then we give some experiment examples using F-LIGA approach and discuss the relationships among the exposure time, pressure and the profile of microstructures. The fabrication process can be used widely in making useful three-dimensional devices.

We describe high-efficiency gratings illuminated by incident lights in the C + L bands as the (de)multiplexers for dense wavelength division multiplexing (DWDM) application. This grating is fabricated in fused silica and replicate in polydimethylsiloxane (PDMS) and polyethylene terephthalate glycol (PETG) with the technology of nanoimprint. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1504–1507, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21719