Dipropylene Glycol Monomethyl Ether Research Articles

Fabrication and characterization of ultra-thin vapour chambers with printed copper powder wick

With the increasing heat flux required in portable electronic devices, ultra-thin vapour chambers (UTVCs) have attracted increasing attention as efficient phase-change heat-transfer components. In this work, a sintered copper powder wick fabricated through a screen-printing process is proposed, providing a novel method for manufacturing large-area and complex-shaped UTVCs. UTVCs with a thickness of 0.55-mm and printed copper powder wicks were fabricated, and the copper powder paste preparation and UTVC manufacturing processes are described in detail. The copper powder paste was made by mixing dipropylene glycol monomethyl ether and copper powder with a particle size of 65–75 μm in a 5:1 ratio. The thickness of the copper layer after sintering was 0.2 mm and its porosity was 59.7%. The heat transfer performance of UTVCs under different liquid-filling ratios and test states was investigated. The results showed that the optimal liquid-filling ratio of the presented UTVCs is 43.2% and that its maximum heat-transfer capability is 6.5 W with a thermal resistance of 0.46 °C/W in the horizontal state. The thermal resistance of the UTVC in the anti-gravity state is more than twice that of the UTVC in the horizontal state. The proposed manufacturing process provides a new solution for the research of the thinner VC and the patterned wick structures.

Parallel Coupling of Ion Mobility Spectrometry and Ion Trap Mass Spectrometry for the Real-Time Alarm Triggering and Identification of Hazardous Chemical Leakages.

Hazardous chemical leakages involved in chemical terrorist attacks and chemical industrial accidents have been posing severe threats to human health and the environment. Vehicle-mounted mass spectrometry (MS) has been developed for continuous, on-road measurements to map the spatial and temporal distributions of hazardous chemicals. However, the detection of chemicals with small temporal scales and spatial scales is always challenging. In this study, a parallel coupling apparatus combining the techniques of ion mobility spectrometry and ion trap MS (p-IMS-ITMS) was developed to improve the detection rate and the time response capability of a stand-alone ITMS system for short time-span chemical tracking. A workflow was also proposed along with the apparatus, where the ITMS system can be triggered, as chemical suspects were discovered with the IMS system. The sampling positions of the ITMS system were investigated and optimized. In addition, a strategy was proposed to diminish the time span of samples from 1.5 to 0.5 s for evaluating the performances of the p-IMS-ITMS system. The detection rate of the stand-alone ITMS system was measured to be only 9.5, 32, and 87.5% for the time span of 0.5, 1, and 1.5 s, respectively. By comparison, the detection rates of the p-IMS-ITMS system were 99.5, 100, and 100%, where the detection rate was increased by a factor of 10 for 0.5 s time span. Moreover, the addition of an IMS system could provide temporal patterns of hazardous chemicals with a resolution of 33 ms. Finally, the potential of the p-IMS-ITMS system for environmental navigation monitoring and assessment was further demonstrated by detecting the leakages of dimethyl methyl phosphonate and dipropylene glycol monomethyl ether.

Follicular pathway role in chemical warfare simulants percutaneous penetration.

Chemical warfare (CW) exposure could be fatal to military and civilians through skin contamination. Our work and others focus on investigating stratum corneum reservoir with less regards to skin appendageal routes including hair follicles. Here, C-14 CW simulants (CWS) with specific activity of 0.1 mCi/ml were tested on abdominal and scalp human cadaver skin using flow-through diffusion system. Quantitative analysis of simulants in skin compartments were performed using scintillation counter. Scalp permeation of dipropylene glycol monomethyl ether (DPGME), diisopropyl methylphosphonate (DIMP) and methyl salicylate (MeS) exceed abdominal skin by 8%, 15%, and 6% (p value < 0.05) of applied dose, respectively. DPGME and DIMP (most hydrophilic) showed earlier permeation peak time (Tmax) through scalp skin at 2 and 4 h, respectively, comparing with 6 h with abdominal skin. The percentage of applied dose of DPGME and DIMP retained in human skin membrane (SC, epidermis, and viable dermis) showed no statistically significant difference between tested abdominal and scalp skin samples (p value >0.05). The percentage of applied dose of MeS in scalp showed higher partitioning in stratum corneum and viable epidermis than abdominal skin (p value <0.05). In conclusion, human scalp showed greater total skin absorption than abdominal skin. This work points to a qualitative importance of high follicular density body regions in percutaneous penetration and suggests that transfollicular pathway might have a significant role in early stage permeation of chemical warfare simulants. However, the difference noticed here between scalp and abdominal skin could be attributed to regional variability in anatomy, physiology, and barrier characteristics.

Noble Metal/Mn3O4 Nanocomposite Systems:from Design to Applications As Ultra-Sensitive Gas Sensors for Nitrogen Mustard Simulant

The efficient detection of chemical warfare agents (CWAs) is of paramount importance in the development of reliable sensing devices for safety applications. In particular, the increased threats of chemical attacks by terrorist organizations have stimulated a significant interest in the early detection of CWAs. Due to the high toxicity and necessity of special infrastructures for storage/manipulation of CWAs, the activities aimed at their detection are carried out on mimicking compounds compatible with lab test security level. In this context, the recognition of di(propylene glycol) monomethyl ether (DPGME), a simulant of the vesicant nitrogen mustard, is of key importance. Among the various devices adopted for CWA sensing, chemoresistive gas sensors based on nanostructured metal oxides offer various advantages, encompassing low cost, limited power consumption, and good stability/sensitivity. To date, DPGME detection has been performed only in a few cases by the use of SnO2-based systems, and the development of highly efficient sensors for its selective monitoring is of primary importance for next-generation devices.Among metal oxides, p-type Mn3O4, a mixed-valence and environmentally friendly multifunctional system, is an attractive candidate for CWAs detection thanks to the tunable Mn redox chemistry and the inherent catalytic properties. On the other hand, gas sensors based on pure p-type materials like Mn3O4 typically feature responses lower than n-type ones, as well as modest sensitivity/selectivity. To circumvent these drawbacks, a viable alternative is the functionalization with noble metals particles, like Ag and Au, that can act as catalytic promoters of the involved chemical reactions at the nanoscale and/or favor the formation of metal/oxide Schottky junctions, improving charge carrier separation.Based on preliminary results on the development of pure Mn3O4 nanomaterials as gas sensors [1,2], we have reported for the first time on the gas-sensing performances of nanocomposite systems based on Mn3O4-M (M = Ag, Au) in DPGME detection [3]. The target materials were obtained by the initial chemical vapor deposition (CVD) of Mn3O4 on polycrystalline Al2O3 substrates, followed by silver or gold radio frequency (RF) sputtering, with the aim of obtaining a high dispersion of metal nanoparticles.The results yielded by a multi-technique characterization highlighted the formation of phase-pure Mn3O4 nanostructures eventually functionalized with Ag or Au and an intimate contact between metal oxide matrix and nanoparticles. These features enabled us to enhance the system sensitivity in the detection not only of standard volatile organic compounds (acetone and ethanol), but also of DPGME, down to the ppb scale. Moreover, the possibility of discriminating between DPGME, on one side, and acetonitrile (CH3CN) or dimethyl methyl phosphonate (DMMP), simulants of HCN (blood agent gas) and Sarin nerve gas, respectively, demonstrates the system selectivity toward the target warfare gas simulant. To shed light on the origin of enhanced selectivity due to functionalization, density functional theory (DFT) based calculations were performed. The results, providing a molecular insight into the interactions between the target systems and DPGME, enabled us to elucidate a dual-site activation mechanism based on the binding of DPGME to both manganese oxide and gold nanoparticles, accounting for the higher functional performances registered for Au-Mn3O4 sensors.As a whole, this study represents an important step forward in the fabrication of highly efficient sensors based on dual metal oxide-metal NP composites. The obtained results pave the way to mastering next-generation sensing devices for real world applications, which will be pursued by additional investigation of the system long-term stability and humidity influence on the resulting functional performances.

Quasi-1D MnO2 nanocomposites as gas sensors for hazardous chemicals

Quasi-1D MnO2 nanocomposite materials (A/MnO2 with A = CuO, SnO2) were developed by a two-step plasma-assisted process, involving the plasma enhanced-chemical vapor deposition (PE-CVD) of MnO2 nanomaterials and their functionalization with copper or tin oxides by radio frequency (RF)-sputtering. A thorough characterization by means of specific surface analytical techniques highlighted the formation of high purity nanocomposites, endowed with a controlled morphology and a tailored spatial dispersion of the functionalizing agents. The target materials were tested as gas sensors for the recognition of hazardous gases [H2 and di(propyleneglycol) monomethyl ether (DPGME) / dimethyl methyl phosphonate (DMMP), the latter used as simulants for chemical warfare agents]. Functional data evidenced the obtainment of low detection limits and promising gas responses, whose improvement with respect to the pristine MnO2 was traced back to the formation of built-in p-n and n-n junctions for CuO/MnO2 and SnO2/MnO2 systems, respectively. The possibility of discriminating between the target analytes depending on the functionalizing species already at moderate working temperatures demonstrates the potential of the developed materials for eventual gas sensing applications under real-world conditions.

Sensing Nitrogen Mustard Gas Simulant at the ppb Scale via Selective Dual-Site Activation at Au/Mn3O4 Interfaces.

The efficient detection of chemical warfare agents (CWAs), putting at stake human life and global safety, is of paramount importance in the development of reliable sensing devices for safety applications. Herein, we present the fabrication of Mn3O4-based nanocomposites containing noble metal particles for the gas-phase detection of a simulant of vesicant nitrogen mustard, i.e., di(propylene glycol) monomethyl ether (DPGME). The target materials were fabricated by chemical vapor deposition of manganese oxide on Al2O3 substrates and subsequent functionalization with silver or gold via radio frequency sputtering. The obtained high purity composites, characterized by an intimate metal/oxide contact, yielded an outstanding efficiency in the detection of DPGME. In particular, sensing of the latter analyte with an ultralow detection limit of 0.6 ppb could be performed selectively with respect to other CWA simulants. In addition, the tuneability of selectivity patterns as a function of metal nanoparticle nature paves the way to the development of efficient and selective devices for practical end uses.

The Effect of Aerosols on the Air Microflora of the Indoor Air

This research work assessed the microflora of rooms sprayed with different insecticides and air freshners with the aim of investigating the effect of the aerosols on the types of microflora in the room environment. Eight (8) different samples of chemical aerosols were used they are: Mobile insecticide(Imidacloprid), Raid multipurpose insect killer(1R-trans Phenothrin), Morten Insecticide(pyrethroids), Rambo Insecticide(pyrethroid compound). as categorized as Insecticides, while Febreze(hydroxypropyl beta-cyclodextrin), Air wick(Dipropylene glycol monomethyl ether (aka dipropylene glycol methyl ether), Glade(allyl 3-cyclohexylpropionate, allyl caproate, benzyl alcohol, butylated hydroxytoluene (BHT) and Top breeze(Cyclodextrin) were purchased as air fresheners/fragrance and eight (8) different rooms were used. Microorganisms isolated from the rooms before and after spraying with aerosols were: Staphylococus aureus, Lactobacillus jensenii, Bacillus coagulans, Aspergillus flavus, Aspergillus niger, Micrococcus spp., Aerococcus viridans, Pediococcus cerevisiae, Streptococcus spp., Aspergillus fumigatus and Aspergillus niger. The result of eight different rooms sprayed with different aerosol as Insecticide and air fresheners showed that, some aerosols were able to inhibit some organisms that were initially present in some rooms while there were introduction of another organisms from some aerosols into some rooms. The occurrence of Staphylococus aureus (100%) was the highest in all the rooms followed by Aspergillus niger (87.5) and A. flavus (75%). Lactobacillus jensenii, Bacillus coagulans and Micrococcus spp. had the lowest frequency of occurrence (12.5%).

Water-based anti-smudge NP-GLIDE polyurethane coatings

An environmentally friendly water-based NP-GLIDE polyurethane (PU) coating has been developed. The term NP-GLIDE as described herein suggests that water, organic solvents, or contaminants in these liquids have no problem to glide down the coating or that the coating bears nano-pools of a grafted lubricating ingredient for dewetting enablement. To prepare a coating, a blocked polyisocyanate and a graft copolymer polyol-g-PDMS consisting of a water-dispersible polyol backbone and poly(dimethyl siloxane) (PDMS) side-chains were co-dispersed in water containing 5.0 vol.% of dipropylene glycol monomethyl ether, cast onto a substrate to evaporate the solvent, and then thermally cured. As the liquid-like PDMS is covalently bound to the polyol backbone, it could not undergo macrophase separation and instead formed nano-pools with diameters of less than 30 nm throughout the polyurethane matrix. Meanwhile, the surface of the coating changed from solid-like to liquid-like due to the surface enrichment by PDMS. Of the three families of polyol-g-PDMS samples that were synthesized and evaluated, only one of these polyol-g-PDMS families yielded NP-GLIDE coatings with superior properties. All of the test liquids with surface tensions above 23 mN/m readily and cleanly slid down the optimized coatings that had a hardness of 3H. Moreover, both marker ink and a commercial paint contracted on these coatings and the contracted ink could be readily and cleanly removed with tissue paper without leaving any traces behind. Moreover, the ink contraction capability was maintained after the writing and erasing test had been performed for more than 30 cycles. The environmental friendliness of the coating formation process and the superior anti-smudge performance of the resultant coatings suggested that they have excellent potential for practical applications.

Dynamics of DiPGME–Water Mixtures in Mesoporous Silica

In this study, we have combined dielectric spectroscopy and 2H NMR to elucidate the molecular dynamics of aqueous solutions of dipropylene glycol monomethyl ether (DiPGME) confined into 2.8 nm pores of MCM-41. The results show that the concentration dependence of the dynamics is completely different compared to the corresponding bulk solutions, where a pronounced nonmonotonic concentration dependence was observed for the glass transition and its related α-relaxation. In the confinement, both the cooperative α-relaxation and the more local β-relaxation are almost unaffected by the water concentration. The main reasons for this seem to be that there is a preferential hydration of the inner pore surfaces, leading to a strong concentration gradient in the pores, as well as ice formation at higher water concentrations (45 wt % and above during heating), also leading to less water and a weaker concentration dependence in DiPGME-rich regions. The β-process is observed in the DS measurements even for confined DiPGME, without any water. This implies that the β-relaxation is strongly enhanced, compared to the α-relaxation, in the confinement, since it could not be clearly observed in the bulk liquid. A β-relaxation due to water was observed in the bulk solutions, but this process was rapidly speeding up with increasing water concentration, while it is basically concentration independent in the confinement. From the NMR measurements, it was also possible to conclude that the α-relaxation of the confined solutions is composed of a number of consecutive small-angle elementary rotational jumps, and that the β-process is related to a spatially restricted motion.

Adsorption of polar molecules on diamond-like carbon films with different trapped charge densities

This work investigates the effect of trapped charge densities present in diamond-like carbon films (DLC) on adsorption of polar molecules on the film surface. Hydrogen-free and hydrogenated DLC films with different hydrogen/carbon contents were produced using filtered-cathodic arc sputtering (FCA-sputtering) and radio-frequency plasma enhanced chemical vapor deposition (RF-PECVD) techniques, respectively. After treating the as-prepared films in a dilute solution of dipropylene glycol monomethyl ether, adsorption of such molecules was found throughout the film surface. Capacitance–voltage (C–V) measurements have shown that the DLC films with lower hydrogen/carbon content inherently have larger trapped charge accumulations within their structures. A charge density of 1600nC/cm2 was measured in a DLC film with a lower hydrogen/carbon content (produced from C2H4 and Ar precursors), while a much smaller charge density of 64nC/cm2 was measured in a DLC film with a higher hydrogen/carbon content (produced from 10% CH4 and 90% H2 precursors). A correlation between charge densities and the degree of polar molecule adsorption was observed. Films with higher charge densities appeared to be more prone to polar molecule adsorption.

754 exposures to reed diffusers reported to the United Kingdom National Poisons Information Service 2010–2014

Objective: The objective of this study is to review the reported toxicity of reed diffuser fragrance liquid which, in addition to essential oils, commonly contains glycol ethers but other ingredients and/or alternatives are 3-methoxy-3-methyl-1-butanol, petroleum distillates, ethanol and isopropanol. Methods: We analysed retrospectively enquiries to the United Kingdom National Poisons Information Service between 1 January 2010 and 31 December 2014. Results: 754 patients were exposed to reed diffusers; the majority (n = 712) were children < 5 years. Ingestion was the most common route of exposure (706 of 754 patients) and involved the liquid alone (n = 570), water beads alone (n = 84), sucking on the reeds (n = 31) or ingesting the liquid and water beads (n = 21). The reported amount of fragrance liquid ingested was known in only 76 of 591 cases (12.9%), with a median (IQR) volume of 20.0 (IQR = 10–40) mL. The WHO/IPCS/EC/EAPCCT Poisoning Severity Score (PSS) was known in 702 of 706 sole ingestions: in 574 (81.3%), the PSS was 0 (asymptomatic); in 117 (16.6%) patients, the PSS was 1 (minor toxicity); in 11 (1.6%), the PSS was 2 (moderate toxicity); there were no patients with features graded PSS 3 (severe toxicity). Significantly (p = 0.008) more patients became symptomatic (PSS 1 and PSS 2) following the ingestion of a reed diffuser containing 3-methoxy-3-methyl-1-butanol than propylene glycol monobutyl ether, though there was no significant difference when compared with those containing dipropylene glycol monomethyl ether (p = 0.181). The most common features following ingestion of fragrance liquid were nausea and vomiting (n = 53), coughing (n = 17) and CNS depression (n = 9). Seven patients suffered eye exposure alone: two developed eye pain and four conjunctivitis. Dermal exposure alone was reported in six patients, two of whom developed skin irritation. Conclusions: The majority of patients in our study developed no features or only minor symptoms following ingestion of reed diffuser fragrance liquid.

MALDI‐TOF Mass Spectrometric Analysis of Chemical Warfare Nerve Agent Simulants

To avoid possible danger, simulants of chemical warfare nerve gas agents, such as dimethyl methylphosphonate (DMMP), triethyl phosphate (TEP), di(propylene glycol) monomethyl ether (DPGMME), methyl salicylate, and diethyl phthalate (DEP), are often used for the development of a new detection and analysis method. In the present study, several MALDI matrices were evaluated to determine the optimal matrix for the simultaneous Matrix‐Assisted Laser Desorption/Ionization Time‐of‐Flight Mass Spectrometry (MALDI‐TOF MS) detection of the above‐mentioned five chemical warfare agent (CWA) simulants, and α‐cyanohydroxycinnamic acid (CHCA) was found to be most effective in detecting all of the simulants without interference from strong background matrix peaks. Furthermore, the limits of detection for the five simulants were roughly estimated with the CHCA matrix. This information is expected to be important for the development of future electrowetting‐on‐dielectrics (EWOD)‐based sample preparation methods that can be subjected to subsequent analysis by MALDI‐TOF MS.

Graphene oxide as sensitive layer in Love-wave surface acoustic wave sensors for the detection of chemical warfare agent simulants

A Love-wave device with graphene oxide (GO) as sensitive layer has been developed for the detection of chemical warfare agent (CWA) simulants. Sensitive films were fabricated by airbrushing GO dispersions onto Love-wave devices. The resulting Love-wave sensors detected very low CWA simulant concentrations in synthetic air at room temperature (as low as 0.2ppm for dimethyl-methylphosphonate, DMMP, a simulant of sarin nerve gas, and 0.75ppm for dipropylene glycol monomethyl ether, DPGME, a simulant of nitrogen mustard). High responses to DMMP and DPGME were obtained with sensitivities of 3087 and 760Hz/ppm respectively. Very low limit of detection (LOD) values (9 and 40ppb for DMMP and DPGME, respectively) were calculated from the achieved experimental data. The sensor exhibited outstanding sensitivity, good linearity and repeatability to all simulants tested. The detection mechanism is here explained in terms of hydrogen bonding formation between the tested CWA simulants and GO.

Volumetric and Ultrasonic Studies of Molecular Interactions in n-Alkoxypropanols + Alkyl Acetates Mixtures at Different Temperatures

Densities and ultrasonic velocities have been measured over the whole composition range for the binary liquid mixtures of dipropylene glycol monomethyl ether (mixture of isomers) {CH3(OC3H6)2OH}, dipropylene glycol monopropyl ether (mixture of isomers) {CH3(CH2)2(OC3H6)2OH}, and dipropylene glycol monobutyl ether (mixture of isomers){CH3(CH2)3(OC3H6)2OH} with alkyl acetates using an Anton Paar DSA 5000 density and speed sound analyzer in the temperature interval (288.15 to 308.15) K and atmospheric pressure. From these experimental data, excess molar volume, VmE and deviations in isentropic compressibility, ΔκS, have been calculated. The computed results of these quantities have been correlated using the Redlich–Kister polynomial equation to obtain the binary coefficients and standard deviations.

Mixing Properties of Binary Liquid Mixtures of Alkoxypropanols with Branched Alkanols at Different Temperatures

Abstract Densities, ρ, and speed of sound, u for binary mixtures dipropylene glycol monomethyl ether and tripropylene glycol monomethyl ether with 2-methyl-1-propanol, 3-methyl-1-butnaol, and 2-methyl-2-butanol at T = 288.15, 298.15, and 308.15 K and atmospheric pressure over the entire range of composition have been measured using an Anton–Paar DSA 5000M densimeter. Excess molar volumes VmE, and deviations in isentropic compressibilities ΔκS have been calculated from experimental densities and speeds of sound. Comparison of the results has been made with earlier results. Deviations in intermolecular free length and deviations in acoustic impedance have also been calculated. The results have been discussed in terms of intermolecular interactions between component molecules of the mixtures.

Time-Weighted Average Sampling of Airborne Propylene Glycol Ethers by a Solid-Phase Microextraction Device

A solid-phase microextraction (SPME) device was used as a diffusive sampler for airborne propylene glycol ethers (PGEs), including propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), and dipropylene glycol monomethyl ether (DPGME). Carboxen-polydimethylsiloxane (CAR/PDMS) SPME fiber was selected for this study. A polytetrafluoroethylene (PTFE) tubing was used as the holder, and the SPME fiber assembly was inserted into the tubing as a diffusive sampler. The diffusion path length and area of the sampler were 0.3 cm and 0.00086 cm2, respectively. The theoretical sampling constants at 30°C and 1 atm for PGME, PGMEA, and DPGME were 1.50 × 10−2, 1.23 × 10−2 and 1.14 × 10−2 cm3 min−1, respectively. For evaluations, known concentrations of PGEs around the threshold limit values/time-weighted average with specific relative humidities (10% and 80%) were generated both by the air bag method and the dynamic generation system, while 15, 30, 60, 120, and 240 min were selected as the time periods for vapor exposures. Comparisons of the SPME diffusive sampling method to Occupational Safety and Health Administration (OSHA) organic Method 99 were performed side-by-side in an exposure chamber at 30°C for PGME. A gas chromatography/flame ionization detector (GC/FID) was used for sample analysis. The experimental sampling constants of the sampler at 30°C were (6.93 ± 0.12) × 10−1, (4.72 ± 0.03) × 10−1, and (3.29 ± 0.20) × 10−1 cm3 min−1 for PGME, PGMEA, and DPGME, respectively. The adsorption of chemicals on the stainless steel needle of the SPME fiber was suspected to be one of the reasons why significant differences between theoretical and experimental sampling rates were observed. Correlations between the results for PGME from both SPME device and OSHA organic Method 99 were linear (r = 0.9984) and consistent (slope = 0.97 ± 0.03). Face velocity (0–0.18 m/s) also proved to have no effects on the sampler. However, the effects of temperature and humidity have been observed. Therefore, adjustments of experimental sampling constants at different environmental conditions will be necessary.

Characterizing and improving performance properties of thin solid films produced by weatherable water-borne colloidal suspensions on bronze substrates

While the development and application for transparent protective coatings for metals continues and broadens, the use of these coatings on high-value outdoor bronze objects, such as statues and architectural elements, requires extensive testing before use. Recent efforts in coatings technology have produced high-performance water-borne latex dispersions containing polyacrylics and poly(vinylidene fluoride) (PVDF) targeting extended coating lifetimes and improved UV resistance. Our studies show that a two-layer polymer film with a solvent based primer (Paraloid™ B-44) and a high performance water-borne topcoat (Kynar Aquatec™ RC-10206) exhibits high impedance as measured by electrochemical impedance spectroscopy. Upon annealing, those films further increased in impedance, suggesting improved corrosion protection compared to unannealed films. When soaking in water, films that contained high loading levels of coalescing agent (Dipropylene glycol monomethyl ether, DPM) in the topcoat formulation resulted in a visible whitening of the basecoat and a decrease in coating resistance. Characterization of the whitened layer by FT-IR indicated the presence of coalescent in the basecoat, suggesting that coalescent migrated from the topcoat into the primer basecoat. Annealing studies were performed to reduce uptake and reverse or inhibit water whitening.

Investigation of Trapped Charges-Induced Stain Formation on RF-PECVD Diamond-Like Carbon Films

This paper reports the investigation of a root cause of stain formation on the surfaces of diamond-like carbon (DLC) films. The DLC thin films are prepared using a radio-frequency plasma enhance chemical vapor deposition (RF-PECVD) technique with C2H4 as a carbon precursor gas. We have observed water spot-like stains on the DLC surfaces after treating the films with a dilute solution of dipropylene glycol monomethyl ether (DPGME). Low voltage-scanning electron microscopy (SEM) is employed to examine the thin layer of agglomerated stains on the surfaces. The results from capacitance-voltage (C-V) measurements show that as-deposited films inherit some trapped charge accumulations within the structure, thereby resulting in the pronounced shift in the flat-band voltage. These trapped charges make the films prone to surface stain formation. Post-annealing of the DLC films at 200 °C in N2 for 1 h has proven to reduce the trapped charge density, and therefore prevent stain formation on the DLC films.

A novel quantificational assessment method of frothers effect on bubble characteristics

A new visual method for quantitative measurement of frothers effect and flotation efficiency was presented. A self-designed electrolytic cell was chosen as the reaction environment with sodium chloride (NaCl) as the electrolyte. Constant current, supplied by a self-designed power supplier and fixed cathode and anode equipment, guaranteed the constant bubble volume per unit time. Even aperture of the cathode material guaranteed the original bubbles size to be uniform. Bubble generating equipment was connected with a microscopical camera. Statistic data collected by high speed charge-coupled device (CCD) and processed by software Sigmascan and Matlab could reflect bubble characteristics. The efficiency of dipropylene glycol monomethyl ether (DPM) and tripropylene glycol n-butyl ethel (TPnB) were measured at the same condition, and 2×10−4 mol/L and 5×10−2 mol/L were found to be the inflexions of bubble size changes.

Density, Speed of Sound, and Refractive Index of Aqueous Binary Mixtures of Some Glycol Ethers at T = 298.15 K

The experimental data of densities (ρ), speeds of sound (u), and refractive indices (nD) of aqueous solutions of different glycol ethers, namely, ethylene glycol iso-propyl ether (EGIPE), ethylene glycol monobutyl ether (EGMBE), diethylene glycol dimethyl ether (DEGDME), diethylene glycol monobutyl ether (DEGMBE), propylene glycol monomethyl ether (PGMME), and dipropylene glycol monomethyl ether (DPGMME), over the entire composition range, at temperature T = 298.15 K, and at one atmospheric pressure have been obtained. The derived parameters such as the apparent molar volume (ϕV) of solute, isentropic compressibility of solution (βS), apparent molar isentropic compressibility (ϕKS) of solute, excess molar volume (VE) of solution, molar refraction ([R]1,2), deviation in refractive index (ΔnD) of solutions, deviation in molar refraction (Δ[R]1,2), and the deviation in isentropic compressibility (ΔβS) have been computed. The limiting apparent molar volumes of solutes (ϕV0), limiting apparent molar isentropic...