Highly stable petroleum pitches provide access to the deep glassy state
Differential scanning calorimetry (DSC) was used to study the fast aging behavior of two petroleum pitch materials despite being only three to five years old.
Chemistry↗
SEARCH · Search NASA
Results for “polymer physics”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Obstructed swelling and fracture of hydrogels
When swelling hydrogels encounter obstacles, they either expand around the obstacles or fracture, depending on obstacle geometry.
Chemistry↗
Tough polycyclooctene nanoporous membranes from etchable block copolymers
Polycyclooctene-polylactide triblock copolymer synthesis and subsequent processingviasolvent casting, polylactide etching, and plasma etching to yield tunable and tough nanoporous membranes with high surface porosities and hydrophilic properties.
Chemistry↗
Interfacial energy as an approach to designing amphipathic surfaces during photopolymerization curing
Photopolymerization induced phase separation (PIPS) is utilized to develop materials in a single step that are hydrophobic on one face and hydrophilic on the other.
Chemistry↗
Probing wrapping dynamics of spherical nanoparticles by 3D vesicles using force-based simulations
This computational study shows that the interactions between nanoparticles and vesicles of diverse shapes are influenced not just by particle size and the extent of wrapping, but also by their initial positions and the sequence of interactions.
Chemistry↗
Block copolymer self-assembly derived mesoporous magnetic materials with three-dimensionally (3D) co-continuous gyroid nanostructure
Magnetic nanomaterials are gaining interest for their many applications in technological areas from information science and computing to next-generation quantum energy materials. While magnetic materials have historically been nanostructured through techniques such as lithography and molecular beam epitaxy, there has recently been growing interest in using soft matter self-assembly. In this work, a triblock terpolymer, poly(isoprene-block-styrene-block-ethylene oxide) (ISO), is used as a structure directing agent for aluminosilicate sol nanoparticles and magnetic material precursors to generate organic–inorganic bulk hybrid films with co-continuous morphology. After thermal processing into mesoporous materials, results from a combination of small angle X-ray scattering (SAXS) and scanning electron microscopy (SEM) are consistent with the double gyroid morphology. Nitrogen sorption measurements reveal a type IV isotherm with H1 hysteresis, and yield a specific surface area of around 200 m 2 g −1 and an average pore size of 23 nm. The magnetization of the mesostructured material as a function of applied field shows magnetic hysteresis and coercivity at 300 K and 10 K. Comparison of magnetic measurements between the mesoporous gyroid and an unstructured bulk magnetic material, derived from the identical inorganic precursors, reveals the structured material exhibits a coercivity of 250 Oe, opposed to 148 Oe for the unstructured at 10 K, and presence of remnant magnetic moment not conventionally found in bulk hematite; both of these properties are attributed to the mesostructure. This scalable route to mesoporous magnetic materials with co-continuous morphologies from block copolymer self-assembly may provide a pathway to advanced magnetic nanomaterials with a range of potential applications.
Chemistry↗
Quantitative measurement of cation-mediated adhesion of DNA to anionic surfaces
Single molecule force spectroscopy quantifies divalent-cation-mediated attraction of double-stranded DNA to an anionic self-assembled monolayer.
Hao, Xian↗
Achieving controllable and reversible snap-through in pre-strained strips of liquid crystalline elastomers
Deformable, elastic materials that buckle in response to external stimuli can display “snap-through”, which involves a transition between different, stable buckled states.
Chemistry↗
In situ aggregation and early states of gelation of gold nanoparticle dispersions
The aggregation and onset of gelation of PEGylated gold nanoparticles dispersed in a glycerol–water mixture is studied by small-angle X-ray scattering and X-ray photon correlation spectroscopy.
Chemistry↗
Shape equilibria of vesicles with rigid planar inclusions
Motivated by recent studies of two-phase lipid vesicles possessing 2D solid domains integrated within a fluid bilayer phase, we study the shape equilibria of closed vesicles possessing a single planar, circular inclusion.
Chemistry↗
Structural determinants of collapse by a monomolecular mimic of pulmonary surfactant at the physiological temperature
DPPC and cholesterol form a hexatic phase in a pulmonary surfactant, indicating that long range order is not required for the alveolar film to avoid collapse and sustain very low surface tensions.
Chemistry↗
Training physical matter to matter
A new paradigm for generating adaptive functionality in materials.
Chemistry↗
Thermal preconditioning of membrane stress to control the shapes of ultrathin crystals
A 2D phospholipid crystal (dark) grows within a fluid vesicle membrane (light), starting as a small flower shape. While the area of the crystal grows progressively, the flower shape is preserved, a result of tension pre-conditioning.
Wan, Hao↗
Impact of water and oleic acid on glycerol monooleate phase transition and bi-continuous structure formation in white oil
Small-angle X-ray scattering was utilized to investigate the morphological transition of glycerol monooleate under various compositions, temperatures, and additives such as water and fatty acids.
Chemistry↗
Molecular dynamics study on the interfacial properties of mixtures of monomers of polyvinylpyrrolidone (PVP)-based battery binders on graphene and graphite surfaces
This study investigates the behavior of two different mixtures of monomers of polyvinylpyrrolidone (PVP)-based battery binders, polyvinylpyrrolidone:polyvinylidene difluoride (PVP:PVDF) and polyvinylpyrrolidone:polyacrylic acid (PVP:PAA), at graphene and graphite interfaces using classical molecular dynamics simulations. The aim is to identify the best performing monomer binder blend and carbon-based material for the design of battery-optimized energy devices. The PVP:PAA monomer binder blend and graphite are found to have the best interaction energies, densification upon adsorption, and more ordered structure. The adsorption of both monomer binder blends is strongly guided by the higher affinity of PVP and PAA monomeric molecules for the surfaces compared to PVDF. The structure of adsorbed layers of PVP:PVDF monomer binder blend on graphene and graphite develops more quickly than PVP:PAA, indicating faster kinetics. This study complements a previous density functional theory study recently reported by our group and contributes to a better understanding of the nanoscopic features of relevant interfacial regions involving mixtures of monomers of PVP-based battery binders and different carbon-based materials. In conclusion, the effect of a blend of commonly used monomer binders on carbon-based materials is essential for obtaining tightly bound anode and cathode active materials in lithium-ion batteries, which is crucial for designing battery-optimized energy devices.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Shear-Induced Gelation of Self-Yielding Active Networks
An enticing feature of active materials is the possibility of controlling macroscale rheological properties through the activity of the microscopic constituents. Using a unique combination of microscopy and rheology we study three dimensional microtubule-based active materials whose autonomous flows are powered by a continually rearranging connected network. We quantify the relationship between the microscopic dynamics and the bulk mechanical properties of these nonequilibrium networks. Experiments reveal a surprising nonmonotonic viscosity that strongly depends on the relative magnitude of the rate of internally generated activity and the externally applied shear. Here, a simple two-state mechanical model that accounts for both the solidlike and yielded fluidlike elements of the network accurately describes the rheological measurements.
36 MATERIALS SCIENCE↗
Nonuniform Flow Dynamics Probed by Nanosecond X-Ray Speckle Visibility Spectroscopy
We report observations of nanosecond nonuniform colloidal dynamics in a free flowing liquid jet using ultrafast x-ray speckle visibility spectroscopy. Utilizing a nanosecond double-bunch mode, the Linac Coherent Light Source free electron laser produced pairs of femtosecond coherent hard x-ray pulses. By exploring anisotropy in the visibility of summed speckle patterns which relates to the correlation functions, we evaluate not only the average particle flow rate in a colloidal nanoparticle jet, but also the nonuniform flow field within. The methodology presented here establishes the foundation for the study of nano- and atomic-scale inhomogeneous fluctuations in complex matter using x-ray free electron laser sources.
47 OTHER INSTRUMENTATION↗