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Hydrogen-bond acidic (HBA) polymers are widely used for the detection of dimethyl methyl phosphonate (DMMP, a simulant of real nerve agents) based on surface acoustic wave (SAW) sensors. This paper presented an HBA polymer PLF, and subsequently the polymer was dissolved into chloroform and spray-coated on a SAW device to fabricate a gas sensor. Then the sensor was equipped into a SAW test platform to investigate its sensitive property to soman vapor and its simulant DMMP at the concentrations below 20 mg/m 3 . Results revealed that the sensor showed high sensitivity to the analyte vapors, furthermore, the response of the sensor to soman vapor was relatively smaller and slower than that to DMMP. Tests to some common interference vapors were studied at the concentration of 10 mg/m 3 , and the results indicated that the sensor showed a good selective property.

Self-assembled monolayers (SAMs) have been used to improve both the positive and negative bias-stress stability of amorphous indium gallium zinc oxide (IGZO) bottom gate thin film transistors (TFTs). N-hexylphosphonic acid (HPA) and fluorinated hexylphosphonic acid (FPA) SAMs adsorbed on IGZO back channel surfaces were shown to significantly reduce bias stress turn-on voltage shifts compared to IGZO back channel surfaces with no SAMs. FPA was found to have a lower surface energy and lower packing density than HPA, as well as lower bias stress turn-on voltage shifts. The improved stability of IGZO TFTs with SAMs can be primarily attributed to a reduction in molecular adsorption of contaminants on the IGZO back channel surface and minimal trapping states present with phosphonic acid binding to the IGZO surface., 27 pages, 6 figures

Selective coacervation with hyaluronic acid (HA), a biocompatible and injectable anionic polysaccharide, was used to isolate a target protein, bovine serum albumin (BSA), with 90% purity from a 1:1 mixture with a second protein of similar pI, β-lactoglobulin (BLG). This separation was attributed to the higher HA-affinity of BSA, arising from its more concentrated positive domain. The values of pH corresponding respectively to the onset of complex formation, coacervation, precipitation, and redissolution (pH(c), pHϕ, pH(p), and pH(d)) were determined as a function of ionic strength I. These pH values were related to critical values of protein charge, Z, and their dependence on I provided some insights into the mechanisms of these transitions. The higher polyanion binding affinity of BSA, deduced from its higher values of pH(c), was confirmed by isothermal titration calorimetry (ITC). Confocal laser microscopy clearly showed time-dependent coalescence of vesicular droplets into a continuous film. Comparisons with prior results for the polycation poly(diallyldimethylammonium chloride) (PDADMAC) show reversal of protein selectivity due to reversal of the polyelectrolyte charge. Stronger binding of both proteins to PDADMAC established by ITC may be related to the higher chain flexibility and effective linear charge density of this polycation.

In this paper, a surface acoustic wave (SAW) sensor coated with a hydrogen-bond acidic (HBA) polymer was introduced to detect styrene vapor. The polymer, PLF, a polysiloxane with a hexafluoroisopropanol functional group was synthesized by hydrosilylation reaction. And subsequently, PLF was dissolved in chloroform, and spray-coated on a 433.92 MHz two-port oscillator SAW device by an airbrush apparatus. Realtime responses of the obtained sensor to styrene vapor and some common interference vapors were studied. High sensitivity and selectivity of the sensor to styrene were demonstrated. The sensitivity was attributed to the OH/π hydrogen bond interaction between PLF and styrene.

Hexafluoroisopropanol (HFIP) was the most widely used functional group for nerve agents detection. However, to incorporate HFIP group into a polymer backbone, highly toxic hexafluoroacetone gas was needed in a conventional synthetic route. In this article, a new route with low toxicity was proposed to synthesize a strong hydrogen-bond acidic (HBA) siloxane polymer by using 2-vinylhexfluoroisopropanol as the raw material in the hydrosilylation reaction. The synthesized fluoroalcoholic linear polysiloxane (LSFA) was characterized by FT-IR, confirming its molecular structure was much similar to SXFA, a well-established HBA polymer synthesized by the conventional route. TGA data verified the adduct's thermal stability. The dimethyl methylphosphonate (DMMP) sensing properties of LSFA and SXFA, along with PLF, were compared basing on the surface acoustic wave (SAW) platform. The results demonstrated that the conventional synthetic route was somewhat difficult to handle and control, while the new route was simpler, easier and was an effective and promising alternative. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4516–4520, 2013

Thin films of β-BaB2O4 were deposited by rf magnetron sputtering on bare Si wafers and optical glass plates. The result of crystallization was sensitive to the substrate crystal structure state and crystallographic orientation of Si cuts.

We have developed a free-standing-mode based triboelectric nanogenerator (F-TENG) that consists of indium tin oxide (ITO) foils and a polytetrafluoroethylene (PTFE) thin film. By utilizing the wind-induced resonance vibration of a PTFE film between two ITO electrodes, the F-TENG delivers an open-circuit voltage up to 37 V and a short-circuit current of 6.2 μA, which can be used as a sustainable power source to simultaneously and continuously light up tens of light emitting diodes (LEDs) and charge capacitors. Moreover, uniform division of the electrode into several parallel units efficiently suppresses the inner counteracting effect of undulating film and leads to an enhancement of output current by 95%. The F-TENG holds prominent durability and an excellent linear relationship between output current and flow rate, revealing its feasibility as a self-powered sensor for detecting wind speed. This work demonstrates potential applications of the triboelectric generator in gas flow harvesters, self-powered air navigation, self-powered gas sensors and wind vector sensors.

Multi-walled carbon nanotube (MWNT) films were prepared on interdigital electrodes by air-brush technique, and their sensing properties to dimethyl methylphosphonate (DMMP) were studied. The MWNT films were observed by scanning electron microscope. The capacitive response to different concentrations of DMMP vapor was investigated at room temperature. The results showed that the capacitance and loss tangent of the air-brush MWNT sensor both decreased rapidly in varying concentrations ranging from 2.4 to 12 ppm. The sensitivity of capacitance was higher than that of the loss tangent at all the concentrations of DMMP vapors. The sensor exhibited high sensitivity and fast response for DMMP vapor detection.

The Uncooled Focus Plane Array (UFPA) infrared detector is widely used in military and civil fields. With the features of small size and not being cooled, the Uncooled Infrared Focal Plane Array (UIRFPA) has become the focus in the current infrared thermal imaging research. A data acquisition system has been designed and implemented for measurement of the UIRFPA. The system includes driver module, acquisition module and signal processing module. The acquisition module based on virtual instrument can achieve high-speed, stable and accurate data acquisition. Meanwhile, combined with visual C+ + (VC) platform, the system realizes data acquisition and real time imaging. Through testing a 240×320 FPA using the test system, the superior performance of the device has been performed. In addition, the imaging effect has been enhanced by eliminating the bad pixels and proofreading the non-uniformity. A new test system for the test of UIRFPA and the exploration of the real-time correction imaging system is presented.

Dual channel surface acoustic wave (SAW) oscillators of two-port SAW resonators were designed for sensor application. A feedback loop were determined by measuring the corresponding open loop and adjusting the point of 0° total phase to exist near to the point of peak gain by variation of coupling inductance value. Two such feedback loops, a mixer and a TTL invertor comprise a dual channel SAW sensor oscillator. To achieve a stable oscillation, incorporation of a power conditioning components and the use of microstrip techniques (50 Ω characteristic impedance and the least inductance path for RF return currents) are necessary. The standard deviation of difference frequency stability of the oscillator of 433.92 MHz is about 3.92. Finally, the dual channel SAW sensor oscillator is used to detect dimehylmethylphosphonate (DMMP) vapor.

Surface transverse wave(STW) resonator was evaluated for the potential use in detecting dimethyl methyl phosphonate (DMMP) vapors. The device’s noise was decreased by the resonator’s low insertion loss and high Q value, while a ZnO wave guide layer was coated on the STW device surface to generate Love wave effect, which enhanced the mass sensitivity of the device. Those contributed to improving the limit of detection(LOD) of sensor. The DMMP sensor is obtained by coating a sensitive layer on the device. The maximum mass sensitivity of 625cm 2 g 1 was obtained and the sensitivity to DMMP vapor was further ehanced by increasing the sensitive layer thickness, which benefited from the low insertion loss of STW device, thus a response of about 5.5kHz upon exposure to 0.1mg/m 3

In this paper, the gas-sensing characteristics of gas sensors for Organic Thin-Film Transistors (OTFTs) with the different ratio of the channel length to width and thickness of the insulating layer were studied. The results showed that the device parameters had the influence on the sensitivity and response time of sensors, and the optimized parameters of OTFT sensors were obtained, that was, the ratio of the channel length to width was between 160 and 640, and the insulating layer was 195 nm in thickness. The OTFT sensor with the α-Sexithiophene (α-6T) film incorporated into a sensitive layer was observed to respond strongly to the trace nitrogen dioxide (NO2) vapor ranging from 0.2 to 1 ppm at room temperature.

Single-walled c arbon nanotube composite films were prepared on quartz crystal microbalance by selfassembly process, and their properties to relative humidity ranging from 20.9% to 80.2% were studied at room temperature. The treated SWNTs were characterized by Fourier trans form infr ared spectroscopy and X-ray photoelectron spectroscopy. Two kinds of SWNT sensors were fabricated using original SWNTs and carboxyl modified SWNTs as humidity sensitive material, respectively. The results showed that the sensitivity of the PDDA/SWNT-COOH humidity sensor was 20.23% higher than the PDDA/SWNT sensor. In contrast, the latter had a superior recovery property and the recovery time was 64 s, while that of the PDDA/SWNT-COOH sensor was 84 s. Both sensors had good repeatability and stability.

An OLED-based gas sensor is fabricated with the device structure as ITO/N,N’-bis(naphthalen-1-yl)N,N’-bis(phenyl)-benzidine (NPB)(30 nm)/tris(8-hydroxy-quinolinatoo)aluminium (Alq3)(50 nm)/poly(3hexylthiophene-2,5-diyl) (P3HT)(x nm)/Mg: Ag (300 nm). The P3HT is applied as the sensitive layer in the OLED-based gas sensor, while red light emission can be observed from the OLED. The response of the device in NO2 and NH3 circumstance is investigated respectively by analyzing its effect on variation of the current density. The results show that the NO2 concentration has an obvious influence on the current density of the device, and the current density decreases faster under the higher NO2 concentration. Meanwhile, the current density of the device increases when it is exposed in the NH3 circumstance. The sensing mechanism of the device is also discussed.

X—ray photoelectron spectroscopy(XPS), Auger electron spectroscopy (AES) and the transmittance spectroscopy from ultraviolet to infrared (UV—IRS) studies were performed for characterization of ferroelectric (Pb,La)TiO3 thin films deposited by the multi—ion—beam reactive cosputtering (MIBRECS) technique. It was found that the chemical composition of the films and the chemical bindings of lead in the near surface region are different from those in the “bulk” region of the films. The films are Pb enriched and the lead atoms exist mainly in the forms of PbOads.(i. e. oxygen—chemisorbed lead) and PbTiO3 in the near surface region, whereas in the bulk region, the chemical composition is in good agreement with stoichiometry and lead atoms exist in the form of PbTiO3. The indirective transition energy gap of PLT thin film was 3. 35eV, and the PLT thin films have a wide transmittance range.

Three polymers were chosen for a surface acoustic wave (SAW) sensor array and a pattern recognition approach. Based on a data set collected from 10 candidate sensitive materials for 12 analytes, the selection was accomplished by principal component analysis (PCA) and cluster analysis(CA) methods. Then, the chosen polymers were deposited on three SAW devices combined into an array, and PCA was adapted to classify three gases with similar structures. The results showed that methanol, ethanol and isopropanol could be clearly distinguished by the SAW sensor array, indicating high selectivity of the sensor array.

A new hydrogen-bond acidic groups functionalized siloxane polymer for quartz crystal microbalance sensors (QCMs) application was synthesized via O-alkylation, claisen rearrange, hydrosilylation and hexafluoroacetone groups (HFA) electrophilic addition reaction. This hexafluoroisopropanol functionalized polysiloxane was confirmed by FT-IR and 1HNMR, and coated onto a AT-cut 8 MHz QCM sensors to investigate its gas sensitive responses to the organophosphorus nerve agent stimulant dimethyl methylphosphonate (DMMP) vapor as well as other organic chemical vapors. The results indicated that frequency change of this functionalized polysiloxane based QCM sensors to the DMMP vapor were completely linear, and with a regression coefficient of 0.9993 in the concentration range of 10-60 ppm. In addition, the sensitivity of the fabricated QCM sensors to DMMP was up to 23.07 Hz/ ppm, and much higher than the other chemical vapors, the detection limits of this fabricated QCM sensors was as low as 0.13 ppm.

Surface acoustic wave (SAW) devices have been widely used for various chemical sensing applications because the sensor signal can be detected by simple and inexpensive electronics. The interactions between target analyte and the sensor surface cause changes in the mechanical, electrical, dielectric properties of the sensing coating deposited onto acoustic transducer. The changes in these properties will lead to changes in the velocity and amplitude of wave modes, which can be measured by frequency and insertion loss (IL) changes when the acoustic element is realized as a delay line or resonator. Among the different sensing coatings, the supermolecules are of considerable interest because the host molecules can be thought as original receptors allowing a specific recognition of guest molecules based on "key-lock" system. In this paper, SAW ethanol gas sensors that utilize the supermolecule of cryptophane-A as sensitive layer have been studied. We synthesized cryptophane-A from vanillyl alcohol using a double trimerisation method and deposited it on the SAW devices to fabricate cryptophane-A based SAW gas sensors. The SAW frequency and insertion loss (IL) were measured using a network analyzer. The frequency shift as the response of the cryptophane-A based SAW sensors to different concentration ethanol was measured at room temperature. It is found that the cryptophane-A based SAW sensor has high sensitivity and good reproductivity to ethanol. The frequency response increased linearly with the concentration of the ethanol.

In this paper, four different series of polymer solutions were presented to study the effects of solution properties on the morphology and diameters of nanofibers, including the polyethersulfone (PES) dissolving in N, N-dimethylformamide, polyvinylpyrrolidone (PVP) in ethanol, poly(acrylic acid) (PAA) in water and poly(vinylidene fluoride) (PVDF) in N, Ndimethyl acetamide. These solutions revealed different conditions of the formation of beads, the spatial structures and the diameter of fibers. The PVDF nanofibers had plenty of small beads on the fibers, while the other three were uniform fibers without beads. The nanofibers of PES, PVP and PVDF showed good three dimensional structures except the PAA fibrous membranes. The change of fiber diameters of PVDF was much larger than that of PVP.

A new hydrogen-bond acidic carbosiloxane polymer for quartz crystal microbalance sensors (QCMs) application was synthesized via O -alkylation, Claisen rearrange, hydrosilylation reaction and functionalized the polysiloxane with trifluoroacetone groups (TFA). The trifluoroisopropanol functionalized polysiloxane was characterized by FT-IR and 1HNMR. And this novel siloxane polymer was coated onto AT-cut 8 MHz QCM sensors to investigate its gas sensitive responses to the organophosphorus nerve agent stimulant dimethyl methylphosphonate (DMMP) vapor as well as other interfering organic vapors. The research work indicated that frequency shifts of the trifluoroisopropanol functionalized polysiloxane based QCM sensor to the DMMP vapor were completely linear, and with a regression coefficient of 0.9973 in the concentration range of 10-60 ppm. In addition, the sensitivity of the fabricated QCM sensors to DMMP was up to 10.64 Hz/ ppm, and much higher than the other interfering vapors, limits of detection (LODs) of the QCM sensors was 0.28 ppm, thus high selectivity to DMMP was demonstrated in this work.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Chemical gas sensor that utilizes poly (2-vinypyridine)-carbon black composition as sensitive film is studied. Poly (2-vinypyridine)-carbon black was deposited on the interdigital microelectrodes via spin-coating method to detect organic vapor and humidity. To study the influence of the carbon black, poly (2-vinypyridine)-carbon black composites with different carbon black content were compared. The various characteristics such as sensitivity and selectivity of poly (2-vinypyridine)-carbon black based sensor have been studied. The results show that proper carbon black content and modified carbon black can improve the sensors' response characteristics.

Hydroxyl group is important for the sensitivity and selectivity of never agents sensors. A new hydrogen bond acidic polymer poly(3,4-dihydroxythiophene) are synthesized from EDOT(ethylene dioxythiophene) by two steps. This material are characterized by UV-vis spectra and FT-IR spectra. The polythiophene polymers with hydroxyl groups are obtained. Composite materials are prepared as films on QCMs (Quartz Crystal Microbalance) and quartz substrates by Spin-coating. The result shows that poly(3,4-dihydroxythiophene) is a sensitive material with good selectivity and adsorbability to organophosphorous vapors.

Poly (3-hexylthiophene)-tin dioxide (P3HT/SnO 2 ) hybrid materials with different P3HT mass ratios were prepared by mechanical mixing. Composite films were prepared on QCM (Quartz Crystal Micr obalance) by spin-coating. The films were characterized by UV-Vis spectrophotometer and SEM. Th e gas sensitive properties of this complex material to two series of organic vapors were investigated. The special groups in the thiophene ring were thought to be a sensory arm, which could be used to detect the target vapors. The sensitiv ity of the films on QCM increases with the molecule weight of alcohols and Cl-substitute methane. It is also in creased with the concentra tion of organic vapors. Keywords: Conjugated poly mer, Vapor adsorption, Poly (3-butoxythiophene), QCM 1. INTRODUCTION In recent years, conjugated polymers have attracted more and more attentions because they exhibit changes in properties such as optical, electric resistance or changes in mass when they interact with certain materials. These properties of conjugated polymers are very suitable for sensor applications. These conjugated polymers include Polythiophenes, polyanilines, polypyrroles, and their derivatives. Polythiophenes, well-known for their electro active properties, ha ve established applications in the microelectronic field, optoelectronics, and chemical sensors, as electronic materials. Those functionalized polythiophenes, with varying side-groups which can be treated as sensory arms shown below

This paper described a procedure based on electrospinning for generating nanofibers with controllable diameters and morphology. When an acetone and N,N-dimethylacetamide (DMAc) mixture solvent containing poly(vinylidene fluoride) (PVDF) was injected through a needle under a strong electric field, nanofibers made of PVDF formed as a result of electrostatic jetting. To control the diameter and morphology of PVDF nanofibers, the solution properties and process parameters were investigated, such as polymer concentration, the ratio of the mixture solvent, feeding rate, applied electric field, and needle-to-collector distance. The fabricated fibers were 30-8000 nm in diameter. The increase in the polymer concentration caused an increase in the fiber diameter. However, the increase in the feeding rate and applied electric field decreased the fiber diameter. Variation in the needle-to-collector distance did not result in significant changes in the fiber diameter. The ratio of the solvent also had a very significant impact on electrospinning. The diameter and morphology of the PVDF nanofibers were characterized by optical microscope and scanning electron microscope (SEM).

In this paper, we study a novel chemical gas sensor based on polymer-carbon black composites for NO2 gas-sensing application. The polymer which is made of polyhexylthiophene mixed with carbon black is employed as the sensing material which is immobilized on the interdigitated microelectrode pair. The electric resistance changes of the sensor to NO 2 at different concentrations have been examined. Also the effect of the humidity to the sensor was examined. The results show that the resistance of the sensor decreases with the NO 2 concentration rising, and it's not sensitive to the humidity.

A bottom contact organic field effect transistor (OFET) was fabricated with poly(3-hexylthiophene) (P3HT) as the channel semiconductor. P3HT thin film was deposited onto a SiO 2 /n-Si substrate by spin coating and electrical characteristics of the P3HT-FET were investigated in a nitrogen flux. A change in the saturation drain-source current (IDS) was observed when device was exposed to different concentrations of nitrogen dioxide (NO 2 ) gas. It was found that the variation in the IDS was remarkable with NO 2 injected in a short time.

A bottom contact pentacene based organic thin film transistor (OTFT) was fabricated in this paper. Pentacene thin film acting both as gas sensing layer and the active layer was formed by vacuum evaporation and was characterized by atomic force microscopy (AFM) and x-ray diffraction (XRD). The results show that the film is highly ordered and has a polycrystalline morphology. The current-voltage characteristics of the OTFT was also investigated. The drain-source current in the saturation region would changed when the OTFT was exposed to alcohol vapor compared to that under an exposure to nitrogen gas. It indicates that the drain-source current can be considered as a key parameter to monitoring chemical species. Such OTFTs devices are promising to act as a novel class of chemical sensors.

The frequency response and the sensitive mechanics of the ST cut quartz SAW sensor with two-port resonator and FPOL sensitive film are theoretically analyzed. The factors affecting the frequency response and the detective sensitivity are systematically researched with the P-matrix method. The results show that, it is necessary to properly choose the width, the thickness and the material parameters of the sensitive film in addition to the optimization of the device structure, in order to improve the detective sensitivity and to reduce the insert loss. The optimized device structure and sensitive film parameters are given in this article, which can provide important reference in designing and analyzing the two-port resonance SAW sensor.

Inorganic nanoparticles SnO 2 and In 2 O 3 were dispersed using an in situ synthesis technique in one of the polyynes polymer, namely poly-2, 5-dimethoxyethynylbenzene(PDMEB) to prepare organic-inorganic nanocomposites PDMEB/SnO 2 and PDMEB/In 2 O 3 . The nanocomposites were characterized by FT-IR, which highlighted the chain organization and the plasticizing effect of the nanoparticles on the polymers. Laser scanning confocal microscope (LSCM) images of the pristine polyynes and of their organic-inorganic nanocomposites, exhibited a growth of nanosized pores on glass substrates. The addition of inorganic nanoparticles clearly makes the pore distribution more uniform. The nanocomposites were deposited on quartz crystal microbalance (QCM) to study their sensitivity to various organic vapors, which showed high selectivity. PDMEB/In 2 O 3 had high sensitivity to THF but PDMEB and PDMEB/SnO 2 had high sensitivity to alcohol (methane, ethane and isopropyl alcohol). In contrast, they had no sensitivity to acetone or chloroform.

In the last few decades, conductive polymers such as polyaniline, polypyrrole, and polythiophene have been widely investigated as effective sensitive materials for chemical gas sensors. Among them, polyaniline (PANI) is frequently used because of its ease and cheap of synthesis, environmental stability and intrinsic redox reaction. However, problems with these conductive polymers include their low processing ability, poor mechanical strength and chemical stability. There are tremendous approaches for the enhancement of mechanical strength and chemical stability of organic materials by combining organic materials with inorganic counterparts in nano-size to form composite materials..which would optimize the characteristics of gas sensors. In the paper, polyaniline/Indium(III) Oxide(PANi/In2O3) nanocomposite thin films was prepared on a quartz substrate by combination techniques of electrostatic self-assembly and in situ chemical oxidation polymerization at 10°C. Infrared spectrum analysis (IR) of the composite and scanning electron microscope(SEM) of nanocomposite thin films were performed. PANi/In 2 O 3 nanocomposite thin film gas sensor was fabricated on AT-Cut quartz crystal microbalance(QCM) of Ag electrodes, and the sensitive properties of gas sensor to CH 4 and CO are characterized and analyzed. The results indicate that PANi/In 2 O 3 thin film gas sensor has good linear sensitive property to CH 4 and CO, and is more sensitive to CH 4 , i.e., the sensitivity is 0.386Hz per ppm when the sensor is exposed to 500 ppm CH 4 while only 0.16Hz per ppm to the same concentration of CO. Such sensitive properties of gas sensor in the constant concentration of CH 4 at different temperature are also characterized. The result shows that temperature would affect the sensitive property of gas sensor.

A visual management platform is designed for wireless temperature and humidity sensor network. The platform offers a multifunctional visual interface, including data management, curve plotting of sensor node, display of topology and data sending and receiving situation, etc, so that the receiving data from sensors can be accessed more conveniently to be used for optimization of network performance. Since ZigBee is specially developed for wireless network of low-rate, low power and low cost, and the platform has been operated efficiently with good compatibility, which is promising for wireless sensor network.

Three series of homologous dendritic amphiphiles--RCONHC(CH(2)CH(2)COOH)(3), 1(n); ROCONHC(CH(2)CH(2)COOH)(3), 2(n); RNHCONHC(CH(2)CH(2)COOH)(3), 3(n), where R = n-C(n)H(2n+1) and n = 13-22 carbon atoms--were assayed for their potential to serve as antimicrobial components in a topical vaginal formulation. Comparing epithelial cytotoxicities to the ability of these homologues to inhibit HIV, Neisseria gonorrhoeae, and Candida albicans provided a measure of their prophylactic/therapeutic potential. Measurements of the ability to inhibit Lactobacillus plantarum, a beneficial bacterium in the vagina, and critical micelle concentrations (CMCs), an indicator of the potential detergency of these amphiphiles, provided additional assessments of safety. Several amphiphiles from each homologous series had modest anti-HIV activity (EC(50) = 110-130 microM). Amphiphile 2(18) had the best anti-Neisseria activity (MIC =65 microM), while 1(19) and 1(21) had MICs against C. albicans of 16 and 7.7 microM, respectively. Two measures of safety showed promise as all compounds had relatively low cytotoxic activity (EC(50) = 210-940 microM) against epithelial cells and low activity against L. plantarum, 1(n), 2(n), and 3(n) had MICs490, 1300, and 940 microM, respectively. CMCs measured in aqueous triethanolamine and in aqueous potassium hydroxide showed linear dependences on chain length. As expected, the longest chain in each series had the lowest CMC-in triethanolamine: 1(21), 1500 microM; 2(22), 320 microM; 3(22), 340 microM, and in potassium hydroxide: 1(21), 130 microM; 3(22), 40 microM. The CMC in triethanolamine adjusted to pH 7.4 was 400 microM for 1(21) and 3900 microM for 3(16). The promising antifungal activity, low activity against L. plantarum, relatively high CMCs, and modest epithelial cytotoxicity in addition to their anti-Neisseria properties warrant further design studies with dendritic amphiphiles to improve their safety indices to produce suitable candidates for antimicrobial vaginal products.

A quartz crystal microbalance (QCM) gas sensor with polysiloxane sensing film was fabricated for detection of dimethyl methyl phosphonate (DMMP), the simulant of chemical warfare agents (CWAs). Poly(methyl-3,3,3-trifluoropropylsiloxane) (PMTFPS) was oxygen plasma treated and then grafted with sulfosalicylic acid (SSA). The resultant SSA modified PMTFPS (SMP) was drop-coated on the electrode of QCM. Compared with the PMTFPS-QCM and SSA-QCM sensors, the sensitivity of SMP-QCM sensor was much higher. However, the SMP films showed less resistance to humidity variations. The selectivity of SMP-QCM sensor to DMMP was also investigated, and better results was showed out after SSA grafted.

A reduced graphene oxide (RGO)–polyethylene oxide (PEO) hybrid film was constructed with composite and bilayer film structures for effective ambient toluene detection. The morphology and chemical properties of the fabricated RGO–PEO hybrid materials were characterized by SEM, and Raman and FTIR spectroscopies, respectively. Sensitive properties of real-time response, sensitivity, repeatability and selectivity to toluene vapor were studied as well at room temperature. The experimental data show that the gas sensors based on composite film have a higher sensitivity than the ones based on bilayer film and pure RGO film at toluene concentrations from 80 ppm to 140 ppm. In addition, the effect of PEO volume fraction and humidity on the sensing performance was also studied. The sensor with a PEO volume fraction of 50% has a better sensitivity and faster response/recovery than others. With respect to selectivity, the gas response of the prepared sensors to toluene was at least 2-fold higher than those to other vapor species, including acetone, ethanol, hydrogen, water and formaldehyde. Furthermore, the sensing mechanism of the fabricated sensors was investigated by comparing the device performance in the presence of dry air or nitrogen as carrier gas.

Humidity sensors featured by the combination of a quartz crystal microbalance (QCM) and polyvinylpyrrolidone (PVP) film were fabricated. PVP films were distributed onto the electrode surfaces of quartz crystal by drop-coating. The electrical characteristics of the devices as a function of relative humidity (RH %) measured in the airtight testing chamber to generate the controlled humidity were tested. The change in frequency of QCM with sensitive film was in situ monitored. Result shows when the polymer-coated QCM exposed to certain humidity circumstance, the change of mass on crystal sensitive surface results in the decrease of resonant frequency. It was found that the increase of shift frequency is proportional to the thickness of polymeric film. In low humidity range less than 50% RH, all of the sensors showed linear characteristics to humidity and mild frequency shift. In high humidity, the frequency shift changed dramatically.Copyright © 2007 by ASME

The authors present a facile, low-cost methodology to fabricate high-performance In-Ga-Zn-O (IGZO) bottom contact, bottom gate thin-film transistors (TFTs) by soft lithography. The IGZO channel and indium tin oxide (ITO) source and drain were patterned using microcontact printing of an octadecylphosphonic acid self-assembled monolayer (SAM). A polymer stamp was used for the pattern transfer of the SAMs, which were then used as a chemical protection layer during wet etching. Excellent pattern transfer was obtained with good resolution and sharp step profiles. X-ray photoelectron spectroscopy indicated that the microcontact printed SAMs can be effectively removed from the ITO source/drain surfaces, allowing a high-quality interface to the IGZO channel for good device performance. Scanning electron microscopy cross-sections of the devices indicate a smooth and defect-free transition regions between the source/drain and semiconductor regions. The fabricated TFTs have negligible gate-leakage currents, high ave...

We report a first-principles study on the geometric, electronic, and magnetic properties of V-doped anatase $\mathrm{Ti}{\mathrm{O}}_{2}$. The $\mathrm{DFT}+U$ (Hubbard coefficient) approach predicts semiconductor band structures for ${\mathrm{Ti}}_{1\ensuremath{-}x}{\mathrm{V}}_{x}{\mathrm{O}}_{2}$ ($x=6.25%$ and 12.5%), in good agreement with the poor conductivity of samples, while the standard calculation within generalized gradient approximation fails. Theoretical results show that V atoms tend to stay close and result in strong ferromagnetism through superexchange interactions. Oxygen vacancy induced magnetic polaron could produce long-range ferromagnetic interaction between largely separated magnetic impurities. The experimentally observed ferromagnetism in V-doped anatase $\mathrm{Ti}{\mathrm{O}}_{2}$ at room temperature may originate from a combination of short-range superexchange coupling and long-range bound magnetic polaron percolation.

Lactoferrin (LF) and β-lactoglobulin (BLG) are among the protein pairs that exhibit heteroprotein coacervation, a unique and relatively unexamined type of liquid-liquid phase separation (LLPS). In prior work we found that LF and BLG undergo coacervation at highly constrained conditions of pH, ionic strength and protein stoichiometry. The molar stoichiometry in coacervate and supernatant is LF : BLG2 1 : 2 (where BLG2 represents the 38 kDa BLG dimer), suggesting that this is the primary unit of the coacervate. The precise balance of repulsive and attractive forces among these units, thought to stabilize the coacervate, is achieved only at limited conditions of pH and I. Our purpose here is to define the process by which such structural units form, and to elucidate the forces among them that lead to the long-range order found in equilibrium coacervates. We use confocal laser scanning microscopy (CLSM), small angle neutron scattering (SANS), and rheology to (1) define the uniformity of interprotein spacing within the coacervate phase, (2) verify structural unit dimensions and spacing, and (3) rationalize bulk fluid properties in terms of inter-unit forces. Electrostatic modeling is used in concert with SANS to develop a molecular model for the primary unit of the coacervate that accounts for bulk viscoelastic properties. Modeling suggests that the charge anisotropies of the two proteins stabilize the dipole-like LF(BLG2)2 primary unit, while assembly of these dipoles into higher order equilibrium structures governs the macroscopic properties of the coacervate.

To achieve both high speed and separation efficiency in the separation of a mixture of nerve and blister agent simulants, a high-aspect-ratio micro-fabricated multi-capillary column (MCC, a 50-cm-long, 450-μm-deep, and 60-μm-wide four-capillary column) was fabricated by the application of the microelectromechanical system (MEMS) techniques. Mixtures of chemical warfare agent (CWA) simulants - dimethyl methylphosphonate (DMMP), triethyl phosphate (TEP), and methyl salicylate - were used as samples. The fabricated MCC allowed for the separation of all the components of the gaseous mixture within 24 s, even when the difference in boiling point was 4°C, as in the case of TEP and methyl salicylate. Furthermore, interfering agents - dichloromethane, ethanol, and toluene - were also included in the subsequent gaseous mixture samples. The boiling point of these six components ranged from 78°C to 219°C. All six components were clearly separated within 70 s. This study is the first to report the clear separation of gas mixtures of components with close boiling points. The column efficiency was experimentally determined to be 12,810 plates/m.