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Results for “polystyrene”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Highly quaternized polystyrene ionomers for high performance anion exchange membrane water electrolysers

Alkaline anion exchange membrane (AEM) electrolysers to produce hydrogen from water remain at an early stage of development, and their performance is far lower than that of systems based on proton exchange membranes. Here, we report an ammonium-enriched anion exchange ionomer that improves the performance of an AEM electrolyser to levels approaching that of state-of-the-art proton exchange membrane electrolysers. Using rotating-disk electrode experiments, we show that a high pH (>13) in the electrode binder is the critical factor for improving the activity of the hydrogen- and oxygen-evolution reactions in AEM electrolysers. Based on this observation, we prepared and tested several quaternized polystyrene electrode binders in an AEM electrolyser. Using the binder with the highest ionic concentration and a NiFe oxygen evolution catalyst, we demonstrated performance of 2.7 A cm -2 at 1.8 V without a corrosive circulating alkaline solution. The limited durability of the AEM electrolyser remains a challenge to be addressed in the future.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Design of polystyrene latex particles covered with polyoxometalate clusters via multiple covalent bonding

In this study, polyoxometalates (POMs) covalently functionalized with methyl methacrylate groups were applied as surfactants in the emulsion polymerization reaction of styrene. Due to the copolymerization of the methyl methacrylate groups and the styrene monomers, the polyoxometalate clusters are covalently grafted onto the surface of polystyrene latex nanoparticles. Finally, such latex particles are fully covered with catalytic POM clusters and might serve as quasi-homogeneous catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Synthesis, characterization and catalytic activity of novel large network polystyrene-immobilized organic bases

In view of searching for efficient polymeric supports for organic bases to be used in environmentally friendly reaction conditions, novel gel-type cross-linked polystyrenes functionalized with diethylamine and 1,5,7-triazabicyclo[4.4.0]dec-5-ene, have been prepared. Moreover, the structural properties and morphology of these catalysts have been determined by extensive solid state NMR experiments, FTIR spectroscopy and SEM/TEM microscopy. SPACeR-supported bases were found to exhibit high catalytic activity in the epoxide ring opening by phenols. Finally, a range of β-substituted alcohols have been readily and regioselectively synthesized.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Fabrication and optical characterization of polystyrene opal templates for the synthesis of scalable, nanoporous (photo)electrocatalytic materials by electrodeposition

Finding solutions to improve the performance of semiconductor light absorbers and catalyst materials remains an outstanding issue that prevents the realization of solar fuel generators. Nanostructuring approaches of photoelectrocatalytic materials have the potential to reduce bulk recombination and improve electron-hole pair separation in semiconductor light absorbers, as well as to increase the active surface area and influence the activity in catalytic systems. Herein, we propose a versatile approach for the synthesis of reproducible, highly homogeneous, large scale nanoporous (photo)electrocatalytic materials for artificial photosynthesis. By identifying and carefully analyzing critical parameters for forming opal templates from solutions of colloidal polystyrene beads (PS), we are able to reproducibly fabricate large area ( > cm 2 ) PS films with high optical quality over a wide diameter range (170-600 nm). Using these PS bead opal films as templates, we demonstrate that electrodeposition is a suitable bottom-up infilling technique to produce scalable, homogeneous, and highly ordered nanoporous (photo)electrocatalytic materials, namely Cu 2 O, BiVO 4 , CuBi 2 O 4 , and Cu. Here, we provide morphological, structural, and optical characterization of the resulting opal replicas. Finally, we demonstrate preliminary integration of the Cu 2 O inverse opal film into a working photocathode under CO 2 reduction conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Depolymerization of polystyrene under ambient conditions

Depolymerization of the addition polymer polystyrene to monomeric styrene is facilitated by mechanochemical processing at room temperature under ambient atmosphere. The reaction occurs in metal-based milling media in concert with scission of macromolecular chains that generates carbon-centered free-radicals detectable by EPR spectroscopy, although the processing is performed in air.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Effect of poly[oligo(ethylene glycol) methyl ether methacrylate] side chain length on the brush swelling behavior in A/B/A–B ternary blends with polystyrene

The phase behavior of ternary blends composed of two homopolymers (A, B) and their corresponding diblock copolymer (A–B) has been widely studied, with emphasis on the volumetrically symmetric isopleth and the formation of bicontinuous microemulsions. However, almost all the previous studies employed linear polymers, and little is known about the impact of polymer architecture on the phase behavior of such ternary blends. Here, in this work, we report the self-assembly of three sets of ternary blends of polystyrene (PS) and poly[oligo(ethylene glycol) methyl ether methacrylate] (POEGMA n ), with different lengths of oligo(ethylene glycol) side chains n. Small-angle X-ray scattering was used to probe the phase behavior at different compositions and temperatures. The order-to-disorder transition temperature was found to be impacted by the side chain length. It was also observed that longer side chains lead to poorer miscibility of homopolymers in the corresponding block, resulting in a more “dry-brush” like swelling behavior.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Imaging polychromator for density measurements of polystyrene pellet cloud on the Large Helical Device

Experimental data on spatial distributions of a pellet cloud electron density are necessary for the development of many applications of pellet injection, namely, plasma fuelling, discharge control, and plasma diagnostics. An improved approach of electron density measurements inside the cloud of a polystyrene pellet ablating in hot plasma of the large helical device is described. Density values of (1-30) × 10{sup 16} cm{sup −3} depending on the background plasma parameters and distance from the solid pellet were measured.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Effects of trifluoromethyl substituents on interfacial and bulk polarization of polystyrene gate dielectrics

The ability to control the bulk and interfacial polarization of dielectric polymers is important to their application in organic electronics. As such, we examine the effect of the trifluoromethyl substituent on poly(3-trifluoromethylstyrene) (P3TFMS) as compared to unsubstituted polystyrene (PS) on the I-V relationships of pentacene-based organic field-effect transistors (OFETs). Single- and double-layered films of these polymers were used, with lower layers crosslinked through vinylbenzocyclobutene comonomers before deposition of upper layers. Control experiments verified that the electronic effect of the crosslinking was negligible. We find that the TFM substituent markedly and independently affects both the initial threshold voltage V th and the nonvolatile, shifted Vth observed after application of static gate voltage, depending on its position adjacent or apart from the pentacene. The trifluoromethyl-bearing polymers exhibit significantly lower magnitude initial threshold voltages (V th,i of ca. -17 V for P3TFMS compared to -35 V for PS), large threshold voltage shifts after charging by application of static electric fields (ΔV th of ca. 32 V for P3TFMS and 17 V for PS) and greater stability of the ΔV th under repeated charge/discharge cycles. These results are consistent with P3TFMS having fewer interfacial trap states but more stable bulk trap states. The results are applicable to organo-electronic systems such as piezoelectrics for energy harvesting and nonvolatile OFETs as memory, sensing, and logic elements.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Synthesis and Spin Trapping Properties of Polystyrene Supported Trifluoromethylated Cyclic Nitrones

Polystyrene supported fluorinated cyclic nitrone spin-traps (Resin-2-HFDMPO and Resin-2-PFDMPO) containing a trifluoromethyl pyrroline-N-oxide core were developed to detect free radicals under flow conditions. A continuous flow EPR technique was used to evaluate the spin trapping properties of these tethered nitrones. While both resins trapped radicals, polymer supported nitrone Resin-2PFDMPO with a longer and more flexible linker showed a more information rich spectrum than Resin-2-HFDMPO.

Nitrone, fluorinated, polymer supported, spin trap↗
DOE OSTI2017

Performance of Different “Lab-On-Chip” Geometries for Making Double Emulsions to Form Polystyrene Shells

Fluid properties and the geometry of lab-on-chip (LOC) designs together affect the formation of double emulsions for making inertial confinement fusion targets. Critical fluid properties include the fluids’ velocities and interfacial tension—a coupled effect that is best characterized by the capillary number (Ca)—and the relative volumetric flow rates (φ). The important geometry of the LOC is the orientation of the channels where they intersect (junction) and the spacing between successive junctions. T-junctions and focus-flow devices were tested. The latter geometry of a double cross (focus flow) performed better: single-emulsion droplets were formed over a wide range of fluid parameters (0.03 < φ < 0.17 and 0.0003 < Ca < 0.001) at the first junction, and double emulsions were formed over a more limited range (φ > 0.5 and Ca < 0.4) at the second junction. A LOC design using the focus-flow design formed water–oil–water (W/O/W) double emulsions with the oil phase containing polystyrene. The double emulsions yielded shells with an outer dimension ranging from 2.3±0.07 mm to 4.3±0.23 mm and a wall thickness ranging from 30 μm to 1.6 mm. Thus, the value of the flow-rate ratio at the second junction provided the most-effective parameter for controlling the inner diameter, outer diameter, and wall thickness of the shell.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Dielectric performance of high permitivity nanocomposites: impact of polystyrene grafting on BaTiO 3 and TiO 2

Polymer nanocomposites are a promising concept to improve energy storage density of capacitors, but realizing their hypothetical gains has proved challenging. The introduction of high permittivity fillers often leads to reduction in breakdown strength due to field exclusion, which intensifies the applied electric field within the polymer matrix near nanoparticle interfaces. This has prompted research in developing new nanoparticle functionalization chemistries and processing concepts to maximize particle separation. Herein, we compare the dielectric performance of blended nanocomposites to matrix free assemblies of hairy (polymer-grafted) nanoparticles (HNPs) that exhibit comparable overall morphology. The dielectric breakdown strength of polystyrene-grafted BaTiO3 (PS@BaTiO3) systems was over 40% greater than a blended nanocomposite with similar loading (~25% v/v BaTiO3). Hairy nanoparticles with TiO2 cores followed similar trends in breakdown strength as a function of inorganic loading up to 40% v/v. Dielectric loss for PS@BaTiO3 HNPs was 2-5 times lower than analogous blended films for a wide frequency spectrum (1 Hz to 100 kHz). For BaTiO3 content above 7% v/v, grafting the polymer chains to the nanoparticle significantly improved energy storage density and efficiency, likely due to the polymer canopy mitigating interfacial transport and restricting particle-particle hot-spots by establishing a finite minimum particle separation.

25 ENERGY STORAGE↗
DOE OSTI2017

Fast heating of fuel assembled in a spherical deuterated polystyrene shell target by counter-irradiating tailored laser pulses delivered by a HAMA 1 Hz ICF driver

Fast heating is a method of heating an assembled high-density plasma into a hot state by irradiating it with short-duration (sub-picosecond), high-intensity ($>$ $10^{18}$ W ${\rm cm}^{-2}$ ) laser pulses before the plasma expands and dissolves hydrodynamically. In this paper, we present detailed experimental results of fast heating fuel assembled in a spherical deuterated polystyrene shell target of 500 ${\mu}$ m diameter and 7 μm thickness with counterbeam illumination by using a HAMA 1 Hz, 5.9 J inertial confinement fusion laser driver with pulse tailoring. These tailored pulses contain three pulses in sequence: a 'foot' pulse of 2.4 J/25 ns, a 'spike' pulse of 0.5 J/300 ps and a 'heater' pulse of 0.4 J/110 fs; these pulses are designed to assemble the fuel and heat it. By varying the energy of the foot pulse, we find that fast heating the fuel is achieved only if the fuel is weakly ablated by the foot pulse and then shock-assembled by the spike pulse into the target centre so that the heater pulse can access the fuel with a focal intensity greater than $10^{18}$ W ${\rm cm}^{-2}$ . Without a foot pulse, the heater pulse contributes to assembling the fuel. For higher foot-pulse energies, the heater pulse drives a hydrodynamic motion with speeds of the order 107 cm ${\rm s}^{-1}$ with intensities of the order $10^{17}$ W ${\rm cm}^{-2}$ , resulting in re-assembling and additional heating of the pre-assembled fuel. Once a shock-assembled core is achieved at the target centre, we succeed qualitatively in fast heating the core for shots in sequence with variations of laser energy within 18%. The coupling efficiency from the heating laser to the core is inferred to be $(10 \pm 2)$ % in total: $(8 \pm 1.6)$ % for the ionized bulk electrons and $(2 \pm 0.4)$ % for the bulk ions. The fusion neutron spectrum detected on the laser axis exhibits peaks at 1.0 MeV, 1.7 MeV and 3.8 MeV. These peaks are attributed to the $C(d, n){\hspace{0pt}}^{13}$ N and $d(d, n){\hspace{0pt}}^3$ He reactions induced by counterpropagating fast deuterons accelerated by the photon pressure of the heating pulses.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Measurement of the sound velocity and Grüneisen parameter of polystyrene at inertial confinement fusion conditions

The principal Hugoniot, sound velocity, and Grüneisen parameter of polystyrene were measured at conditions relevant to shocks in inertial confinement fusion implosions, from 100 to 1000 GPa. The sound velocity is in good agreement with quantum molecular dynamics calculations and all tabular equation of state models at pressures below 200 GPa. Above 200 GPa, the experimental results agree with two of the examined tables, but do not agree with the most recent table developed for design of ICF experiments. The Grüneisen parameter increases with density below ~3.1 g/cm 3 and approaches the asymptotic value for an ideal gas after complete dissociation. This behavior is in good agreement with quantum molecular dynamics results and previous work but is not represented by any of the tabular models. Finally, the discrepancy between tabular models and experimental measurement of the sound velocity and Grüneisen parameter is sufficient to impact simulations of ICF experiments.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Shock-induced metallization of polystyrene along the principal Hugoniot investigated by advanced thermal density functionals

To date, none of the ab-initio molecular dynamics simulations of polystyrene, often used as an ablator material in inertial confinement fusion targets, with the standard ground-state exchange-correlation (XC) functional in density-functional theory can satisfactorily agree with experiments in terms of reflectivity measurements. Here, we use recently developed thermal strongly constrained and appropriately normed Laplacian dependent meta-generalized gradient approximation XC density functional (T-SCAN-L) and thermal hybrid XC density functional (KDT0) to show that the inclusion of thermal and inhomogeneity effects is crucial for accurate prediction of structural evolution and corresponding insulator-metal transition (IMT) during shock compression. Optical reflectivity calculated as an indicator of IMT is in perfect accord with experimental data.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Solid-to-plasma transition of polystyrene induced by a nanosecond laser pulse within the context of inertial confinement fusion

Laser Direct Drive (LDD) Inertial Confinement Fusion (ICF) involves irradiating a spherical target of thermonuclear fuel coated with an ablator, usually made of polystyrene. Laser energy absorption near the target surface leads to matter ablation, hydrodynamic shocks, and ultimately capsule implosion. The conservation of spherical symmetry is crucial for implosion efficiency, yet spatial modulations in laser intensity can induce nonuniformities, causing the laser imprint phenomenon. Understanding laser imprint, especially considering the initial solid state, is essential for advancing LDD ICF. A first microscopic model of solid-to-plasma transition was built in 2019, accounting for laser absorption in the solid state with a band structure based ionization model. This model has been improved to include chemical fragmentation and a more accurate description of electron collision frequency in various matter states. The latest development involves assessing the model reliability by comparing theoretical predictions with experimental observations. Despite the success of this approach, questions remain, leading to further investigations and observations under different irradiation conditions. This work presents an experiment with a nanosecond pulse, taking into account hydrodynamic effects, and measures transmission dynamics over the entire laser beam area to observe two-dimensional effects. As a result, the objective is to adapt the theoretical model, couple it with a hydrodynamic code, and observe additional effects related to the initial solid state.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗