Low Film Thickness Research Articles

"Stabilization" of Amorphous Ketoprofen in Thin Films.

It has been shown that depositing ketoprofen as thin films on glass substrates has a stabilizing effect on the amorphous state of ketoprofen. Polyethylene glycol (M = 6000 g/mol) was mixed with ketoprofen in a wide range of concentrations. Amorphous thin films were prepared by spin coating and subjected to storage conditions with different levels of relative humidity. The films were characterized by specular X-ray diffraction and atomic force microscopy to assess their stability in dry to wet atmospheres. In a dry atmosphere, the amorphous films remained stable for up to 4 months, although ketoprofen possesses a glass transition temperature of -6 °C. However, when subjected to a humid atmosphere (over 50% relative humidity), ketoprofen tends to crystallize in the amorphous films. At low solution concentrations (i.e., low film thickness and low ketoprofen loading) and high humidity, only nanometer-size crystals could be detected. Increasing the polymer mass ratio may favor or prevent crystallization of ketoprofen in the amorphous films depending on its own crystallization behavior in those films.

Equilibrium phase behavior of gyroid-forming diblock polymer thin films.

Thin-film confinement of self-assembling block polymers results in materials with myriad potential applications-including membranes and optical devices-and provides design parameters for altering phase behavior that are not available in the bulk, namely, film thickness and preferential wetting. However, most research has been limited to lamella- and cylinder-forming polymers; three-dimensional phases, such as double gyroid (DG), have been observed in thin films, but their phase behavior under confinement is not yet well understood. We use self-consistent field theory to predict the equilibrium morphology of bulk-gyroid-forming AB diblock polymers under thin-film confinement. Phase diagrams reveal that the (211) orientation of DG, often observed in experiments, is stable between nonpreferential boundaries at thicknesses as small as 1.2 times the bulk DG lattice parameter. The (001) orientation is stable between modestly B-preferential boundaries, where B is the majority block, while a different (211)-oriented termination plane is stabilized by strongly B-preferential boundaries, neither of which has been observed experimentally. We then describe two particularly important phenomena for explaining the phase behavior of DG thin films at low film thicknesses. The first is "constructive interference," which arises when distortions due to the top and bottom boundaries overlap and is significant for certain DG orientations. The second is a symmetry-dependent, in-plane unit-cell distortion that arises because the distorted morphology near the boundary has a different preferred unit-cell size and shape than the bulk. These results provide a thermodynamic portrait of the phase behavior of DG thin films.

Flow and heat transfer characteristics of offset unsubmerged jets impinging on rotating disks

A study of an unsubmerged jet impinging on a heated rotating disk is conducted to investigate the multi-phase flow dynamics and heat transfer characteristics. The effects of varying the disk rotational speeds, ranging from 240 to 16,000 revolutions per minute, and the jet location, ranging from a symmetrical condition to offset conditions up to 80 % of the disk radius, are analysed. The jet nozzle diameter and the ratio of the jet impingement distance to nozzle diameter are held constant at 4 mm and 10, respectively. The Volume of Fluid method is employed to model the two-phase flow, with a conjugate heat transfer boundary condition applied at the fluid–solid interface. A moving mesh rotation model is employed for the computations. The results show that changes in jet offset positions at different rotational speeds lead to distinct flow and temperature patterns, significantly impacting the heat transfer on the top surface of the rotating disk. With decreasing jet offset distances, better overall heat transfer performance and lower surface average temperatures are obtained. While increasing rotational speed up to 1930 revolutions per minute at a high jet offset (0.6) enhanced the average Nusselt number by 50 %, at very high speeds (16,000 revolutions per minute), low film thickness or poor oil contact with the hot surface reduced heat transfer performance to 3 %. Consequently, maximum average Nusselt numbers are achieved at mid rotational speeds (1930 revolutions per minute) and small jet offsets (less than 0.4). Poor heat transfer performance was observed at higher speeds (above 1930 revolutions per minute) and larger offsets (above 0.4). A new correlation is proposed for the average heat transfer based on the rotational Reynolds number and jet offset location.

Effects of silica fume/ultrafine fly ash on the rheology and hardening of alkali-activated slag-waste ceramic powder paste

Fast setting and high viscosity are the two main obstacles to obtain desired rheological properties of alkali-activated materials (AAMs). This work aims to remove these obstacles by using a simple yet effective approach via introducing ultra fines with different characteristics. Here in the systems of alkali-activated slag-waste ceramic powder, the mechanism behind the effect of various ultra fines on rheological and hardened properties is studied. Results show that the introduction of ultrafine fly ash (UFFA) is beneficial to maintain good rheological properties and control setting, yet adding silica fume (SF) harms fresh performance due to the extremely low liquid film thickness. By 1H NMR and interstitial solution analysis, the large water demand for wetting SF rather than its dissolution, has been demonstrated to cause the insufficient dissolution of slag, which leads to lower Al3+ and Ca2+ concentrations and less precipitation of early gels. However, once gels start to precipitate, shorter particle spacing favors the rapid formation of percolation network in SF-systems, thus resulting in higher yield stress, viscosity and setting rate, as well as a faster decrease in mobile water. Furthermore, the incorporation of 5 %-10 % UFFA provides superior fresh performance and hardened properties. The results and relevant mechanisms of this study are essential towards better development of high-performance AAMs.

Effects of kinematic hardening of mucus polymers in an airway closure model

The formation of a liquid plug inside a human airway, known as airway closure, is computationally studied by considering the elastoviscoplastic (EVP) properties of the pulmonary mucus covering the airway walls for a range of liquid film thicknesses and Laplace numbers. The airway is modeled as a rigid tube lined with a single layer of an EVP liquid. The Saramito–Herschel–Bulkley (Saramito-HB) model is coupled with an Isotropic Kinematic Hardening model (Saramito-HB-IKH) to allow energy dissipation at low strain rates. The rheological model is fitted to the experimental data under healthy and cystic fibrosis (CF) conditions. Yielded/unyielded regions and stresses on the airway wall are examined throughout the closure process. Yielding is found to begin near the closure in the Saramito-HB model, whereas it occurs noticeably earlier in the Saramito-HB-IKH model. The kinematic hardening is seen to have a notable effect on the closure time, especially for the CF case, with the effect being more pronounced at low Laplace numbers and initial film thicknesses. Finally, standalone effects of rheological properties on wall stresses are examined considering their physiological values as baseline.

12‐3: Materialization of Mid‐Resolution Quantum Dot Color Converters on G2.5 TFT‐LCD Production Line for Micro‐LED Displays

This study proposes a mass production solution for quantum dot color converter (QDCC) of mid‐resolution micro‐LED displays. Therefore, a gray bank materials and QD photoresist (PR) with high optical density (OD) and low film thickness were developed. The gray bank materials can achieve OD = 1.08 and a reflectivity of over 25% at a thickness of 4 μm. The red QDPR has OD = 1.93 at 3 μm, and the green QDPR has OD = 1.58 at 3.3 μm. Finally, a 125 PPI and 7‐inch QDCC were fabricated using a G2.5 TFT‐LCD production line, and the optimal material formula and process conditions were determined. Optical analysis shows color point uniformity with STD < 1.3%, indicating that this solution can provide excellent in‐plane uniformity.

Early-stage silver growth during sputter deposition on SiO2 and polystyrene – Comparison of biased DC magnetron sputtering, high-power impulse magnetron sputtering (HiPIMS) and bipolar HiPIMS

The integration of silver thin films into optoelectronic devices has gained much interest due to their exceptional properties in terms of conductivity and compatibility with flexible substrates. For this type of application, ultra-thin layers are desirable, because of their optical transparency. Standard direct current magnetron sputtering (DCMS) is known to lead to undesirable formation of islands at low effective film thicknesses on typical substrates like SiO2 or polystyrene (PS). Therefore, in this study, we explore high-power impulse magnetron sputtering (HiPIMS) with optional further acceleration of metal ions by biasing the substrate or an additional positive pulse (bipolar HiPIMS) for the fabrication of ultra-thin silver layers. The morphology and electrical properties of ultra-thin silver layers with selected effective thicknesses are characterized on SiO2 and PS substrates. The growth evolution of characteristic parameters is further investigated by in-situ grazing-incidence small-angle X-ray scattering (GISAXS). The results show that HiPIMS deposition yields films with a higher density of clusters than DCMS leading to a percolation threshold at lower effective film thicknesses. This effect is amplified by further ion acceleration. Thus, we suggest HiPIMS as a promising technique for fabricating ultra-thin, conductive layers on organic and oxide substrates.

Substrate Modifications for Stability Improvements of Flexible Perovskite Solar Cells

Flexible perovskite solar cells (fPSCs) prepared on flexible plastic substrates exhibit poor stability under illumination in ambient, due to inferior gas barrier properties of plastic substrates. Herein, we investigated effect of different modifications of the back surface of the substrate to improve stability under illumination in ambient. T80 under simulated solar illumination at maximum power point in ambient (ISOS‐L‐1) can be increased from 80 h to over 350 h with the deposition of a single layer (by spin‐coating or by atomic layer deposition (ALD)). While ALD layers resulted in the best T80 value and significant reduction of the oxygen transmission rate compared to other modifications even for very low film thickness (≈10 nm), a simple solution‐processed spin‐on‐glass barrier layer also enables significant (more than 4 times) improvement in device stability. This work illustrates the importance of barrier layers for decreasing the ingress of oxygen and moisture into fPSCs through the plastic substrate.

Thermocapillary central lamella recess during droplet impacts onto a heated wall

We experimentally observe a new phenomenon, the formation of a toroidal region of lower film thickness in the center of the lamella formed during high Weber number water droplet impacts onto smooth heated walls. This region forms around the air bubble, which is entrapped during the initial impact phase at the impact center. Our study encompasses a variation of the droplet size, impact velocity, surface wettability and temperature. We show how this phenomenon can be explained considering a two-step process involving thermocapillary convection in two separate regions: The temperature gradient along the surface of the entrapped air bubble caused by heat conduction induces flow that pumps warmer liquid to the lamella-ambient interface due to the Marangoni effect. The non-uniform temperature distribution along it then causes fluid acceleration in the radial direction, depleting the fluid volume around the bubble in a self-amplifying manner. We use direct numerical simulations of a stagnant liquid film with an enclosed bubble at the wall to confirm this theory.

Experimental Study on Macroscopic Spray and Fuel Film Characteristics of E40 in a Constant Volume Chamber

In the modern industrial field, there is a strong emphasis on energy-saving and emission reduction. Increasing the amount of ethanol in ethanol–gasoline blends has the potential to replace fossil fuel gasoline more effectively, improving energy efficiency and lowering emissions. The interaction between liquid fuel film generation on the piston crown and spray impingement in the combustion chamber in the setting of GDI engines has a substantial impact on particle emissions and engine combustion. In this study, 92# gasoline and ethanol by volume are combined to create the ethanol–gasoline blend E40. The spray characteristics and film properties of both gasoline and the intermediate proportion ethanol–gasoline blend E40 were researched utilizing a constant volume combustion platform and the schlieren method and refractive index matching (RIM) approach. The results show that, for 0.1–25 operating conditions, gasoline consistently displays greater macroscopic spray characteristic parameters than E40. This shows that gasoline fuel spray evaporation is superior to E40. Similar results are seen in the analysis of wall-attached fuel films, where the volume and thickness of the gasoline film are less than those of the E40 film under the given operating conditions. In contrast, E40 consistently exhibits stronger macroscopic spray characteristic values than gasoline under the 0.1–150 and 0.4–150 operating conditions, along with lower film thickness and volume. As a result, under these two operating conditions, E40 fuel performs better during spray evaporation.

Two dimensional landscape of ferromagnetic domains and the resulting magnetization curves

Recently, Kittel’s theory of ferromagnetic domains in thin films in one dimension, i. e. with the domains extended infinitely over one in-plane direction and with the anisotropy axis oriented perpendicular to the film was revisited by considering the film thickness and unbalanced domains with up and down magnetization, yielding to the computation of magnetic hysteresis [C. M. Teodorescu, Res. Phys. 46 (2023) 106287]. In this work, the above study is extended to samples featuring two-dimensional domain landscapes, for materials with strong magnetic anisotropy, typically characterized by a superunitary ratio between the anisotropy energy and the stray field energy densities. This allows one to compute the most stable structures for vanishing average magnetization 〈M〉 together with hysteresis curves for thin films with perpendicular magnetic anisotropy and two-dimensional rectangular domains and also for thin films with in-plane magnetic anisotropy. For two-dimensional films with perpendicular magnetic anisotropy, the most stable structure for 〈M〉 = 0 is found to be that with domains infinitely elongated along one in-plane direction, i. e. the one-dimensional case treated in the preceding work. For thin stripes with in-plane magnetization, the domain size l is approximately linear with the stripe lateral size d for low film thickness, while for large film thicknesses it follows a Kittel-like law, but as function of the stripe size l ∼ d1/2. For in-plane magnetized thin films of infinite lateral extent, the most stable structure is the single domain. As for hysteresis curves, the two-dimensional case with perpendicular magnetic anisotropy is shown to evolve from a 2D landscape derived from the checkerboard structure, but with unbalanced domains for magnetization near saturation, towards one-dimensional domain structures for lower magnetization. In some cases and depending also on the demagnetization factor, the one-dimensional case is not reached, and the film exhibit 2D structures on the whole range of the magnetization curve. The hysteresis obtained for thin magnetic stripes with in-plane magnetization also can exhibit a rich structure, with minor cycles on the wings of the magnetization curves evolving towards „normal” hysteresis (again, depending on the film thickness, stripe lateral size and demagnetization factor). An infinite thin film with in-plane anisotropy features a steplike magnetization dependence on the applied field.

Effect of different Cu:Co film concentrations on photocatalytic reactions of ethanol, MB, AMX, and Cr(VI): A study of film properties & effects of photooxidation

Wastewater treatment is an urgent challenge of the 21st century, and photocatalysis represents a promising approach. However, much of the research has focused on powdered photocatalysts and complex, costly methods, leading to limitations in practical applications. This study introduces an innovative approach to produce Cu:Co thin films with different weight ratios (70:30, 50:50, and 30:70) by the low-cost dip-coating technique. The photocatalytic activity of Cu:Co films was investigated through the photooxidation of alcohol (EtOH), degradation of dye (MB), antibiotic (AMX), and photoreduction of heavy material ions (Cr(VI)) under sunlight irradiation. The results clearly show that higher Cu concentration ratios (70:30%) resulted in smoother surfaces (49.7 nm), higher droplet contact angle (72.43°), smaller particles (67 nm), lower film thickness (365 nm), narrower band gap (1.68 eV), higher transmittance (26.7%), and improved degradation of MB (78% for 4 h) and amoxicillin (43% for 45 min). Conversely, higher Co ratios may yield contrasting effects in most cases. The photoreduction of Cr(VI) showed similar results for Cu:Co films with 70:30 and 50:50 ratios, reaching 42.81% and 43.82% for 30 min, respectively. The effect of the ethanol photooxidation process significantly reduced the roughness, film thickness, and band gap in all Cu:Co films while enhancing transmittance, except for the 50:50 Cu:Co ratio. Cu:Co films are ideal for practical applications such as photoreaction processes due to their efficiency, sustainability, and stability.

Root causes for corrosion on painted steel structures in marine environments

AbstractOur understanding of the failure mechanisms of coatings, for example, cathodic disbonding, corrosion creep, blistering, and cracking, have been developed to a high level over the past decades. However, knowing what actually causes coatings to fail in the field is also important. Several atmospheric field tests of coating with duration 2–9 years have been published, showing that epoxy‐based heavy‐duty protective coating systems with zinc‐rich primers have high resistance against corrosion creep from damages in the coating. Despite this, scribe creep corrosion has become the most important evaluation parameter in standardized testing. In this work, inspection pictures from an offshore oil and gas platform, a ballast water tank system, and two coastal road bridges have been analyzed with respect to the root cause for initiation of corrosion on coated steel. The results show that corrosion mainly initiates at edges and welds. Between 50% and 90% of the corrosion attacks could be attributed to this, depending on the type of structure. The paint failed due to low film thickness, that is, the wet paint retracts from sharp edges in the surface so that the cured film has reduced barrier properties.

Comparison of the Physical Properties of Three Resin-Based Root Canal Sealers: An In-Vitro Study.

Objectives: This in-vitro study aimed to evaluate the physical properties of three resin-based root canal sealers, including BETA-RCS, AH26, and Adseal. Materials and Methods: Flowability, film-thickness, solubility, and radiopacity of BETA-RCS, AH26, and Adseal sealers were evaluated according to ISO 6876/2012 specifications. Three samples of each sealer were used to test each of the properties. Results: The results revealed that the flow rate (mm) of BETA-RCS, Adseal, and AH26 were 23.06±1.58, 22.5±4.23, and 21.85±1.71, respectively. Film-thickness values (µm) for BETA-RCS, Adseal, and AH26 sealers were 52.33±2.51, 18.66±0.57, and 52±2, respectively. No significant difference was observed regarding film-thickness between AH26 and BETA-RCS (P>0.05), while Adseal showed significantly lower film-thickness (P˂0.05). The highest and lowest solubility were related to BETA-RCS and Adseal, respectively. However, all sealers had acceptable solubility and radiopacity. Conclusion: The findings of the current study suggested that all three root canal sealers including BETA-RCS, AH26, and Adseal had similar properties based on ISO 6876 standard criteria. As such, they could be viable choices for facilitating effective root canal procedures. Further long-term clinical studies are warranted to assess their performance and success rates in actual endodontic cases.

Physicochemical, Biological, and Antibacterial Properties of Four Bioactive Calcium Silicate-Based Cements.

Calcium silicate-based cement (CSC) is a pharmaceutical agent that is widely used in dentistry. This bioactive material is used for vital pulp treatment due to its excellent biocompatibility, sealing ability, and antibacterial activity. Its drawbacks include a long setting time and poor maneuverability. Hence, the clinical properties of CSC have recently been improved to decrease its setting time. Despite the widespread clinical usage of CSC, there is no research comparing recently developed CSCs. Therefore, the purpose of this study is to compare the physicochemical, biological, and antibacterial properties of four commercial CSCs: two powder-liquid mix types (RetroMTA® [RETM]; Endocem® MTA Zr [ECZR]) and two premixed types (Well-Root™ PT [WRPT]; Endocem® MTA premixed [ECPR]). Each sample was prepared using circular Teflon molds, and tests were conducted after 24 h of setting. The premixed CSCs exhibited a more uniform and less rough surface, higher flowability, and lower film thickness than the powder-liquid mix CSCs. In the pH test, all CSCs showed values between 11.5 and 12.5. In the biological test, cells exposed to ECZR at a concentration of 25% showed greater cell viability, but none of the samples showed a significant difference at low concentration (p > 0.05). Alkaline phosphatase staining revealed that cells exposed to ECZR underwent more odontoblast differentiation than the cells exposed to the other materials; however, no significant difference was observed at a concentration of 12.5% (p > 0.05). In the antibacterial test, the premixed CSCs showed better results than the powder-liquid mix CSCs, and ECPR yielded the best results, followed by WRPT. In conclusion, the premixed CSCs showed improved physical properties, and of the premixed types, ECPR exhibited the highest antibacterial properties. For biological properties, none of these materials showed significant differences at 12.5% dilution. Therefore, ECPR may be a promising material with high antibacterial activity among the four CSCs, but further investigation is needed for clinical situations.

Thermo-viscous influence on the mechanical seal performance in a reactor coolant pump (RCP)

The mechanical seal performance in reactor coolant pump (RCP) is of great importance for the efficient and safe operation of primary loop in nuclear power plant. The sealing medium filling inside the seal encounters strong thermal gradient. In this paper, thermo-viscous effect on sealing characteristics with two typical mechanical seal faces, namely the tapered-end-face and wave-tilt-dam, is numerically studied, by introducing the temperature-viscosity equation according to the real physical properties of the sealing medium. Performance of mechanical seal with two different temperature-viscosity equations are compared. In addition, the influence of thermo-viscous effect on cavitation is also analyzed. It is revealed that the temperature-viscosity variation significantly influences the internal flow field, temperature field, two-phase distribution, and the opening force as well. With low base film thickness, the temperature difference will reduce 58% as considering the thermal effect on viscosity, and the difference in leakage may be as high as 43%. Also, the prediction of cavitation under small film thickness indicates that the thermo-viscous effect decreases the cavitating area. This work contributes to the mechanical seal design and performance prediction by assessing the thermal influences on viscosity of seal medium, and meanwhile revealing the effect on the possible cavitation event.

Strategies to engineer FeCoNiCuZn high entropy alloy composition through aqueous electrochemical deposition

Low melting point elements are often incompatible with alloy synthesis methods that involve high temperatures, and thus, high entropy alloys containing zinc (Zn) have not been explored much to date, hindering the development of new alloy system investigations. In such cases, electrodeposition can be a useful alternative for the synthesis of multi-component (MCA)/high entropy alloys (HEA) which contain elements with large differences in their melting point and those that cannot be easily synthesized through established conventional/melting-casting routes. Though electrodeposition is an age-old technique, exploration of this synthesis route for fabricating HEAs is recently gaining attention, and more specifically, aqueous medium electrodeposition is still in its infancy. The current work reports a HEA containing Zn, namely, FeCoNiCuZn, through electrodeposition in an aqueous medium utilizing sulfate salts. Electrodeposition was carried out by varying different input parameters, namely, duty cycles (input pulse parameters), pH, and substrate roughness. Through these different input parameters, their effects on the composition, phase, and morphology of the deposited films are a matter of investigation. Observations revealed that the composition of the electrodeposited FeCoNiCuZn thin film is highly dependent on the input pulse parameters and the pH, whereas the substrate roughness played no observable significant role, probably owing to the use of pulsed waveform and the very low film thickness (∼ 500 nm). The compositional characterization of the electrodeposited FeCoNiCuZn showed the presence of a high percentage of Cu (> 50 at.%) at lower duty cycles (< 0.75), whereas higher duty cycle (> 0.75) resulted in FeCoNiCuZn HEAs with all five elements in almost equal proportion. Alternatively, lower pH (≤ 1.5) led to high Cu content in the thin film, whereas higher pH (≥ 2.5) resulted in a multi-elemental deposition.

Electrochemical Oxidation of Methane to Methanol on Electrodeposited Transition Metal Oxides

Electrochemical partial oxidation of methane to methanol is a promising approach to the transformation of stranded methane resources into a high-value, easy-to-transport fuel or chemical. Transition metal oxides are potential electrocatalysts for this transformation. However, a comprehensive and systematic study of the dependence of methane activation rates and methanol selectivity on catalyst morphology and experimental operating parameters has not been realized. Here, we describe an electrochemical method for the deposition of a family of thin-film transition metal (oxy)hydroxides as catalysts for the partial oxidation of methane. CoOx, NiOx, MnOx, and CuOx are discovered to be active for the partial oxidation of methane to methanol. Taking CoOx as a prototypical methane partial oxidation electrocatalyst, we systematically study the dependence of activity and methanol selectivity on catalyst film thickness, overpotential, temperature, and electrochemical cell hydrodynamics. Optimal conditions of low catalyst film thickness, intermediate overpotentials, intermediate temperatures, and fast methanol transport are identified to favor methanol selectivity. Through a combination of control experiments and DFT calculations, we show that the oxidized form of the as-deposited (oxy)hydroxide catalyst films are active for the thermal oxidation of methane to methanol even without the application of bias potential, demonstrating that high valence transition metal oxides are intrinsically active for the activation and oxidation of methane to methanol at ambient temperatures. Calculations uncover that electrocatalytic oxidation enables reaching an optimum potential window in which methane activation forming methanol and methanol desorption are both thermodynamically favorable, methanol desorption being favored by competitive adsorption with hydroxide anion.

Comparison of the performances of different drying enhancers for waterborne polyvinyl alcohol films

AbstractWaterborne polyvinyl alcohol (PVA) films show lower environmental impact but render high residual solvent on account of hydrophilicity of PVA and low volatility of water. Plasticizers have shown high potential to act as drying enhancers in some recent studies. Plasticizers triphenyl phosphate (TPP) and polyethylene glycol (PEG400) with their favorable chemical structures and relatively low molar masses are promising options. Their performances in drying waterborne PVA films are compared with the plasticizers used in earlier works, at different initial wet film thicknesses, polymer contents, enhancer contents, and enhancer molar masses. Films were solvent casted by drying PVA‐water solutions in a substrate. TPP causes maximum lowering of the residual solvent and does this at high drying rate corresponding to low initial wet film thickness and PVA content. The least value of residual solvent is 0.20% at optimum TPP loading. The next best residual solvent results of 0.21% and 0.59% are, respectively, exhibited by PEG400 and PEG6000, but at low drying rate for high wet film thickness, for both the enhancers; however, at high drying rate for low wet film thickness anomalous skinning increased the residual solvent. At 0.51%, Capstone FS‐63 also gives good results and at high drying rate. Their relative performances are correlated to the viscosity of cast solutions, glass transition temperature of films (DSC), and chemical structures of the polymer and enhancers. TPP thus proved to be most effective. SEM showed dense films and disappearance of defects with optimum loading of TPP, and TGA/DTG showed thermally stable coatings. In spite of the higher cost of TPP it can have useful specialized applications that exploit its excellent flame retardance features.

Pixelated Micropolarizer Array Based on Carbon Nanotube Films.

A micropolarizer array (MPA) that can be integrated into a scientific camera is proposed as a real-time polarimeter that is capable of extracting the polarization parameters. The MPA is based on highly aligned carbon nanotube (CNT) films inspired by their typical anisotropy and selectivity for light propagation over a wide spectral range. The MPA contains a dual-tier CNT pixel plane with 0° and 45° orientations. The thickness of the dual-tier structure of the CNT-based MPA is limited to less than 2 μm with a pixel size of 7.45 μm × 7.45 μm. The degree of polarization of the CNT-MPA reached 93% at a 632 nm wavelength. The specific designs in structure and semiconductor fabrication procedures are described. Compared with customary MPAs, CNT-based MPA holds great potential in decreasing the cross-talk risk associated with lower film thickness and can be extended to a wide spectral range.