Search NASA⌕ Search

SEARCH · Search NASA

Results for “Polymer Science”

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.

At least 937 records · Page 52
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

The Light Microscopy Module A Facility Overview-History and Science

We will share a brief history and provide a science overview of the many accomplishments of the Light Microscopy Module (LMM), a microscope that has been operating in the microgravity environment of the International Space Station (ISS) since 2010. It will be removed in October 2021. It was initially outfitted for the Constrained Vapor Bubble – Wickless Heat Pipe experiment. It was later reconfigured and upgraded many times to support a broad portfolio of Physical science and Biological experiments including: Complex Fluids, Colloids, Macro-Molecular Biophysics, Protein Crystals, and Plant Biology. The LMM has enabled many significant studies and discoveries and has seen its fair share of pleasant surprises. These include recording order arising out of disorder, e.g., systems of colloids that were glasses on Earth crystallizing to form large defect-free crystals, nematic ordering of elliptical colloids, and colloidal-polymer systems crystallizing. The LMM science teams have also seen how to improve product stabilizers once the effects of sedimentation on Earth were removed; they were able to see which tagged genes express in plants when gravity is removed, telling them which genes are essential for growing plants in space; they’ve tested protein crystal growth models; checked models for creating bijel electrodes that turn batteries into fast-charging supercapacitors; tested many forms of colloidal self-assembly: including those using depletion attraction, magnetic fields, and critical Casimir forces; they’ve observed explosive bubble nucleation in a wickless heat pipe, and much more. This work has been supported by the NASA Biological and Physical Sciences (BPS) Division and the ISS Program Office, Johnson Space Center Code OZ and Code OB, the Center for the Advancement of Science in Space (CASIS) / ISS National Lab, EPSCoR, and ISS international partners from ESA – the Netherlands and Italy, CSA, JAXA and S. Korea, and by Space Act Agreements with Procter and Gamble (P&G).

Colloids↗
DOE OSTI2017

Polypeptoid polymers: Synthesis, characterization, and properties

Polypeptoids, a class of peptidomimetic polymers, have emerged at the forefront of macromolecular and supramolecular science and engineering as the technological relevance of these polymers continues to be demonstrated. The chemical and structural diversity of polypeptoids have enabled access to and adjustment of a variety of physicochemical and biological properties (eg, solubility, charge characteristics, chain conformation, HLB, thermal processability, degradability, cytotoxicity and immunogenicity). These attributes have made this synthetic polymer platform a potential candidate for various biomedical and biotechnological applications. Furthermore, this review will provide an overview of recent development in synthetic methods to access polypeptoid polymers with well–defined structures and highlight some of the fundamental physicochemical and biological properties of polypeptoids that are pertinent to the future development of functional materials based on polypeptoids.

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

Shape Recovery with Concomitant Mechanical Strengthening of Amphiphilic Shape Memory Polymers in Warm Water

Maintaining adequate or enhancing mechanical properties of shape memory polymers (SMPs) after shape recovery in an aqueous environment are greatly desired for biomedical applications of SMPs as self-fitting tissue scaffolds or minimally invasive surgical implants. Here we report stable temporary shape fixing and facile shape recovery of biodegradable triblock amphiphilic SMPs containing a poly(ethylene glycol) (PEG) center block and flanking poly(lactic acid) or poly(lactic-co-glycolic acid) blocks in warm water, accompanied with concomitant enhanced mechanical strengths. Differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WXRD) and small-angle X-ray scattering (SAXS) analyses revealed that the unique stiffening of the amphiphilic SMPs upon hydration was due to hydration-driven microphase separation and PEG crystallization. We further demonstrated that the chemical composition of degradable blocks in these SMPs could be tailored to affect the persistence of hydration-induced stiffening upon subsequent dehydration. These properties combined open new horizons for these amphiphilic SMPs for smart weight-bearing in vivo applications (e.g. as self-fitting intervertebral discs). In conclusion, this study also provides a new material design strategy to strengthen polymers in aqueous environment in general.

36 MATERIALS SCIENCE↗
DOE OSTI2018

The meniscus-guided deposition of semiconducting polymers

The electronic devices that play a vital role in our daily life are primarily based on silicon and are thus rigid, opaque, and relatively heavy. However, new electronics relying on polymer semiconductors are opening up new application spaces like stretchable and self-healing sensors and devices, and these can facilitate the integration of such devices into our homes, our clothing, and even our bodies. So, while there has been tremendous interest in such technologies, the widespread adoption of these organic electronics requires low-cost manufacturing techniques. Fortunately, the realization of organic electronics can take inspiration from a technology developed since the beginning of the Common Era: printing. Here, this review addresses the critical issues and considerations in the printing methods for organic electronics, outlines the fundamental fluid mechanics, polymer physics, and deposition parameters involved in the fabrication process, and provides future research directions for the next generation of printed polymer electronics.

36 MATERIALS SCIENCE↗
DOE OSTI2022

EXPANSE: A time-of-flight EXPanded Angle Neutron Spin Echo spectrometer at the Second Target Station of the Spallation Neutron Source

EXPANSE, an EXPanded Angle Neutron Spin Echo instrument, has been proposed and selected as one of the first suite of instruments to be built at the Second Target Station of the Spallation Neutron Source at the Oak Ridge National Laboratory. This instrument is designed to address scientific problems that involve high-energy resolution (neV– μeV) of dynamic processes in a wide range of materials. The wide-angle detector banks of EXPANSE provide coverage of nearly two orders of magnitude in scattering wavenumbers, and the wide wavelength band affords approximately four orders of magnitude in Fourier times. This instrument will offer unique capabilities that are not available in the currently existing neutron scattering instruments in the United States. Specifically, EXPANSE will enable direct measurements of slow dynamics in the time domain over wide Q-ranges simultaneously and will also enable time-resolved spectroscopic studies. The instrument is expected to contribute to a diverse range of science areas, including soft matter, polymers, biological materials, liquids and glasses, energy materials, unconventional magnets, and quantum materials.

47 OTHER INSTRUMENTATION↗
DOE OSTI2022

Fabrication, thermal analysis, and heavy ion irradiation resistance of epoxy matrix nanocomposites loaded with silane-functionalized ceria nanoparticles

This paper describes a detailed understanding of how nanofillers function as radiation barriers within the polymer matrix, and how their effectiveness is impacted by factors such as composition, size, loading, surface chemistry, and dispersion. Here, we designed a comprehensive investigation of heavy ion irradiation resistance in epoxy matrix composites loaded with surface-modified ceria nanofillers, utilizing tandem computational and experimental methods to elucidate radiolytic damage processes and relate them to chemical and structural changes observed through thermal analysis, vibrational spectroscopy, and electron microscopy. A detailed mechanistic examination supported by FTIR spectroscopy data identified the bisphenol A moiety as a primary target for degradation reactions. Results of computational modeling by the Stopping Range of Ions in Matter (SRIM) Monte Carlo simulation were in good agreement with damage analysis from surface and cross-sectional SEM imaging. All metrics indicated that ceria nanofillers reduce the damage area in polymer nanocomposites, and that nanofiller loading and homogeneity of dispersion are key to effective damage prevention. The results of this study represent a significant pathway for engineered irradiation tolerance in a diverse array of polymer nanocomposite materials. Numerous areas of materials science can benefit from utilizing this facile and effective method to extend the reliability of polymer materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Expanding the utility and range of quantum and polymer dots for multiplexed super resolution fluorescence imaging in plants (Final Progress Report)

The emission spectra of plant pigments currently limit the number of fluorescent colors that can be imaged simultaneously and, therefore, the number of cellular components that can be imaged within a single experiment. Hence, developing fluorescent tags and a microscope system that can image beyond the visible range (NIR) would greatly enhance plant imaging capabilities. Extending imaging into the NIR would support the interrogation of multiple proteins/molecules simultaneously, but would inevitably decrease spatial resolution due to the increase of the diffraction limit of light. To address this need, we propose to develop a super resolution fluorescence imaging (SRFI) platform that would allow imaging of NIR-emitting molecules, as well as quantum dots (QDs) and polymer dots (Pdots).

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Polymer-Infiltrated Metal–Organic Frameworks for Thin-Film Composite Mixed-Matrix Membranes with High Gas Separation Properties

Thin-film composite mixed-matrix membranes (TFC-MMMs) have potential applications in practical gas separation processes because of their high permeance (gas flux) and gas selectivity. In this study, we fabricated a high-performance TFC-MMM based on a rubbery comb copolymer, i.e., poly(2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl] ethyl methacrylate)-co-poly(oxyethylene methacrylate) (PBE), and metal–organic framework MOF-808 nanoparticles. The rubbery copolymer penetrates through the pores of MOF-808, thereby tuning the pore size. In addition, the rubbery copolymer forms a defect-free interfacial morphology with polymer-infiltrated MOF-808 nanoparticles. Consequently, TFC-MMMs (thickness = 350 nm) can be successfully prepared even with a high loading of MOF-808. As polymer-infiltrated MOF is incorporated into the polymer matrix, the PBE/MOF-808 membrane exhibits a significantly higher CO 2 permeance (1069 GPU) and CO 2 /N 2 selectivity (52.7) than that of the pristine PBE membrane (CO 2 permeance = 431 GPU and CO 2 /N 2 selectivity = 36.2). Therefore, the approach considered in this study is suitable for fabricating high-performance thin-film composite membranes via polymer infiltration into MOF pores.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRSDate not supplied

Testing Bacteria Resistance Polymers Onboard The ISS

Student Payload Opportunity with Citizen Science (SPOCS) is a program funded by NASA to inspire the Artemis generation Scientific Question: How does microgravity impact the efficacy of bacteria resistant polymers? Experimental apparatus to be sent to ISS with 2 polymer chemistry candidates coated on Al 6061 alloy coupons Staphylococcus Epidermidis bacteria strain to simulate growth of superficial dermal bacteria.

bacteria↗
DOE OSTI2017

A Review on Organic Polymer-Based Thermoelectric Materials

Converting heat energy directly into useable electricity by harvesting low-cost energy resources, such as solar energy and the waste heat, has attracted great interest recent years. Thermoelectricity offers a promising technology to convert heat from solar energy and to recover waste heat from industrial sectors and automobile exhausts. Classically, a number of inorganic compounds have been considered as the best thermoelectric materials. Organic materials in particular intrinsically conducting polymers had been considered as competitors of classical thermoelectric since their figure of merit has been improved several orders of magnitude in last year. In addition, the applications of thermoelectric polymers at low temperatures have shown various advantages such as easy and low cost of fabrication, light weight, and flexibility. Therefore, organic thermoelectric materials will be the best candidates to compete with inorganic materials in the future. In this review, we focused on exploring different types of organic thermoelectric materials and the factors affecting their thermoelectric properties, and discussed various strategies to improve the performance of thermoelectric materials. In addition, a review on theoretical studies of thermoelectric transport in polymers is also given.

36 MATERIALS SCIENCE↗
NASA NTRS1986

Physics through the 1990s: Scientific interfaces and technological applications

The volume examines the scientific interfaces and technological applications of physics. Twelve areas are dealt with: biological physics-biophysics, the brain, and theoretical biology; the physics-chemistry interface-instrumentation, surfaces, neutron and synchrotron radiation, polymers, organic electronic materials; materials science; geophysics-tectonics, the atmosphere and oceans, planets, drilling and seismic exploration, and remote sensing; computational physics-complex systems and applications in basic research; mathematics-field theory and chaos; microelectronics-integrated circuits, miniaturization, future trends; optical information technologies-fiber optics and photonics; instrumentation; physics applications to energy needs and the environment; national security-devices, weapons, and arms control; medical physics-radiology, ultrasonics, MNR, and photonics. An executive summary and many chapters contain recommendations regarding funding, education, industry participation, small-group university research and large facility programs, government agency programs, and computer database needs.

Source record↗
DOE OSTI2016

Controlling the aqueous solubility of PNIPAM with hydrophobic molecular units

The effect of co-polymerization of thermo-sensitive polymers with hydrophilic or hydrophobic co-monomers on the LCST and the structure of proximal water remains a fundamental and challenging problem. Here, in this study, we employ all-atom molecular dynamics simulations to investigate the aqueous solubility of a thermo-sensitive polymer, poly(N-isopropylacrylamide) (PNIPAM), a hydrophobic polymer polystyrene (PS) and block co-polymers of PNIPAM-co-PS. The simulations of pure oligomers of PNIPAM and PS and their co-polymers are conducted below and above the LCST of PNIPAM to elucidate the effect of increase in number of PS units in PNIPAM-co-PS co-polymers on the coil-to-globule transition of PNIPAM and structure of proximal water. Our simulations suggest that while the LCST of pure PNIPAM oligomers is strongly associated with the structural changes in the proximal water molecules present near PNIPAM, inclusion of PS units disrupts the interactions between PNIPAM and water and promotes the faster dehydration of PNIPAM chains above its LCST. This phenomenon is manifested by a coil-to-globule transition in PNIPAM chains present in PNIPAM-co-PS co-polymers at much shorter times as compared to the pure PNIPAM oligomers. Our results also reveal that with increase in the number of PS units in PNIPAM-co-PS co-polymers the coil-to-globule transition is accelerated.

36 MATERIALS SCIENCE↗
DOE OSTI2020

A comparative experimental study of the hygroscopic and mechanical behaviors of electrospun nanofiber membranes and solution–cast films of polybenzimidazole

This article reports a comparative experimental study of the hygroscopic and mechanical behaviors of electrospun polybenzimidazole (PBI) nanofiber membranes and solution-cast PBI films. As-electrospun nonwoven PBI nanofiber mats (with the nanofiber diameter of ~250 nm) were heat-pressed under controlled temperature, pressure and duration for the study; lab-made solution-cast PBI films and commercially available PBI films (the PBI Performance Product Inc., Charlotte, NC) were used as the control samples. Thermogravimetric and microtensile tests were utilized to characterize the hygroscopic (moisture absorption) and mechanical properties of the PBI nanofiber membranes at varying heat-pressing conditions, which were further compared to those of solution-cast PBI films. Experimental results indicated that the PBI nanofiber membranes carried slightly higher thermal stability and less hygroscopic properties than those of solution-cast PBI films. In addition, heat-pressing conditions significantly influenced the mechanical properties of the resulting PBI nanofiber membranes. The stiffness and tensile strength increase with increasing either the heat-pressing pressure or duration, and relevant mechanisms were explored. Here, the present study provides a rational understanding of the hygroscopic and mechanical behaviors of electrospun PBI nanofiber membranes and solution-cast PBI films that are beneficial to their reliable cutting-edge applications in high-temperature filtration, polymer electrolyte membranes (PEMs), etc.

25 ENERGY STORAGE↗
DOE OSTI2024

Using Data-Science Approaches to Unravel Insights for Enhanced Transport of Lithium Ions in Single-Ion Conducting Polymer Electrolytes

Solid polymer electrolytes have yet to achieve the desired ionic conductivity (>1 mS/cm) near room temperature required for many applications. This target implies the need to reduce the effective energy barriers for ion transport in polymer electrolytes to around 20 kJ/mol. In this work, we combine information extracted from existing experimental results with theoretical calculations to provide insights into ion transport in single-ion conductors (SICs) with a focus on lithium ion SICs. Through the analysis of temperature-dependent ionic conductivity data obtained from the literature, we evaluate different methods of extracting energy barriers for lithium transport. The traditional Arrhenius fit to the temperature-dependent ionic conductivity data indicates that the Meyer–Neldel rule holds for SICs. However, the values of the fitting parameters remain unphysical. Our modified approach based on recent work (Macromolecules 2023, 56, 15, 6051), which incorporates a fixed pre-exponential factor, reveals that the energy barriers exhibit temperature dependence over a wide range of temperatures. Using this approach, we identify anions leading to the energy barriers <30 kJ/mol, which include trifluoromethane sulfonimide (TFSI), fluoromethane sulfonimide (FSI), and boron-based organic anions. In our efforts to design the next generation of anions, which can exhibit the energy barriers <20 kJ/mol, we have performed density functional theory (DFT) based calculations to connect the chemical structures of boron-based anions via the binding energy of cation (lithium)-anion pairs with the experimentally derived effective energy barriers for ion hopping. Not only have we identified a correlation between the binding energy and the energy barriers, but we also propose a strategy to design new boron-based anions by using the correlation. This combined approach involving experiments and theoretical calculations is capable of facilitating the identification of promising new anions, which can exhibit ionic conductivity >1 mS/cm near room temperature, thereby expediting the development of novel superionic single-ion conducting polymer electrolytes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Modeling Mesoscale Processes of Scalable Synthesis Final Scientific/Technical Report

This is the final scientific and technical report for this award. Molecular dynamics (MD) is a powerful tool to study biomolecules at the nanoscale. One of its main limitations however is that such simulations typically require a timestep of 1 femtosecond while reactions and conformational changes typically happen on the time scale of 1 microsecond or more. This discrepancy severely restricts the impact of this method. We have developed a series of algorithms to mitigate this problem and allow predicting long-time scale events using much shorter simulations. The method is based on the concurrent adaptive sampling method. It consists in using probabilistic weights for trajectories and biasing the sampling such that rare but important trajectories, e.g., those that go over energy barriers and lead to relevant conformational changes in the molecule, are observed with much higher frequency that in a standard MD simulation. We will demonstrate below that this approach has been very successful. In collaboration with Jay Grate at PNNL we have applied this novel method to the study the triazine polymers, which can be con gured using different types of side chains in order to adopt different 3-dimensional structures. We have found novel stable con- formations and have analyzed the impact of side chain modifcations on the native folded shape of the polymer. Direct MD simulations would have been untractable for this problem. The method of replica exchange was also used successfully to calculate free energy profiles, in particular for cis-trans torsional angle changes with high energy barriers. Studying molecules at the atomistic scale is essential to design new molecules in chemical engineering, such as the triazine polymers developed by Grate, in material science to study the strength of metals for examples (e.g., dislocation dynamics), or in biochemistry to understand how proteins fold and how they interact with ligands (a key step in designing drugs). Although new hardware makes these simulations increasingly faster (e.g., GPU, Anton from DE Shaw Research), new algorithms are key to making these methods more tractable and increase their impact. At this point, because of limitations in modeling, one of the main techniques for advancing science remains to a large extent numerous and costly experiments. For exam- ple, when designing drug, where multiple variants must be screened, the ability to run tests on a computer rather than experimentally testing with high throughput methods thousands of compounds would represent a signi cant advance with broad benefits for the public at large.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Lignin-Based Polyurethanes: Opportunities for Bio-Based Foams, Elastomers, Coatings and Adhesives

Polyurethane chemistry can yield diverse sets of polymeric materials exhibiting a wide range of properties for various applications and market segments. Utilizing lignin as a polyol presents an opportunity to incorporate a currently underutilized renewable aromatic polymer into these products. In this work, we will review the current state of technology for utilizing lignin as a polyol replacement in different polyurethane products. This will include a discussion of lignin structure, diversity, and modification during chemical pulping and cellulosic biofuels processes, approaches for lignin extraction, recovery, fractionation, and modification/functionalization. We will discuss the potential of incorporation of lignins into polyurethane products that include rigid and flexible foams, adhesives, coatings, and elastomers. Finally, we will discuss challenges in incorporating lignin in polyurethane formulations, potential solutions and approaches that have been taken to resolve those issues.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Machine Learning on a Robotic Platform for the Design of Polymer–Protein Hybrids

Polymer–protein hybrids are intriguing materials that can bolster protein stability in non-native environments, thereby enhancing their utility in diverse medicinal, commercial, and industrial applications. One stabilization strategy involves designing synthetic random copolymers with compositions attuned to the protein surface, but rational design is complicated by the vast chemical and composition space. Here, a strategy is reported to design protein-stabilizing copolymers based on active machine learning, facilitated by automated material synthesis and characterization platforms. The versatility and robustness of the approach is demonstrated by the successful identification of copolymers that preserve, or even enhance, the activity of three chemically distinct enzymes following exposure to thermal denaturing conditions. Although systematic screening results in mixed success, active learning appropriately identifies unique and effective copolymer chemistries for the stabilization of each enzyme. Overall, this work broadens the capabilities to design fit-for-purpose synthetic copolymers that promote or otherwise manipulate protein activity, with extensions toward the design of robust polymer–protein hybrid materials.

36 MATERIALS SCIENCE↗