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At least 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Anthradithiophene (ADT)-Based Polymerized Non-Fullerene Acceptors for All-Polymer Solar Cells

Realizing efficient all-polymer solar cell (APSC) acceptors typically involves increased building block synthetic complexity, hence potentially unscalable syntheses and/or prohibitive costs. Here we report the synthesis, characterization, and implementation in APSCs of three new polymer acceptors P1–P3 using a scalable donor fragment, bis(2-octyldodecyl)anthra[1,2-b : 5,6-b’]dithiophene-4,10-dicarboxylate (ADT) co-polymerized with the high-efficiency acceptor units, NDI, Y6, and IDIC. Further, all three copolymers have comparable photophysics to known polymers; however, APSCs fabricated by blending P1, P2 and P3 with donor polymers PM5 and PM6 exhibit modest power conversion efficiencies (PCEs), with the champion P2-based APSC achieving PCE=5.64 %. Detailed morphological and microstructural analysis by AFM and GIWAXS reveal a non-optimal APSC active layer morphology, which suppresses charge transport. Despite the modest efficiencies, these APSCs demonstrate the feasibility of using ADT as a scalable and inexpensive electron rich/donor building block for APSCs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Composite Correlated Molecular Orbital Theory Calculations of Ring Strain for Use in Predicting Polymerization Reactions

Strained ring systems play an important role in synthesis and can be characterized by the ring strain energy (RSE). The RSE of 3, 4, 5, and 6 membered saturated and unsaturated ring systems containing N, O, P, and S heteroatoms and H, F, SiMe 3 , and SO 2 Me substituents were calculated at the G3(MP2) composite correlated molecular orbital theory level using up to 5 models to predict the RSE. Generally, the RSE decreased as ring size increased with a substantial decrease from 4 to 5 membered rings. Replacement of a ring CH 2 with P or S reduced the RSE, consistent with less angle strain. The RSE for unsaturated systems were generally greater than for saturated systems due to increased angle strain. No general trends were found with respect to substituent effects. In conclusion, the RSE values suggest that 3-pyrroline and 2-pyrroline and their derivatives may be able to support ring opening metathesis polymerization and warrant further study.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Toward Standardized Microscale Tensile Testing for Two‐Photon Polymerization‐Fabricated Materials in Liquid

Two-photon polymerization (TPP) enables the fabrication of intricate 3D microstructures with submicron precision, offering significant potential in biomedical applications like tissue engineering. In such applications, to print materials and structures with defined mechanics, it is crucial to understand how TPP printing parameters impact the material properties in a physiologically relevant liquid environment. Herein, an experimental approach utilizing microscale tensile testing (μTT) for the systematic measurement of TPP-fabricated microfibers submerged in liquid as a function of printing parameters is introduced. Using a diurethane dimethacrylate-based resin, the influence of printing parameters on microfiber geometry is first explored, demonstrating cross-sectional areas ranging from 1 to 36 μm 2 . Tensile testing reveals Young's moduli between 0.5 and 1.5 GPa and yield strengths from 10 to 60 MPa. The experimental data show an excellent fit with the Ogden hyperelastic polymer model, which enables a detailed analysis of how variations in writing speed, laser power, and printing path influence the mechanical properties of TPP microfibers. The μTT method is also showcased for evaluating multiple commercial resins and for performing cyclic loading experiments. Collectively, this study builds a foundation toward a standardized microscale tensile testing framework to characterize the mechanical properties of TPP printed structures.

mechanical characterization↗
DOE OSTI2022

A multi-material platform for imaging of single cell-cell junctions under tensile load fabricated with two-photon polymerization

We previously reported a single-cell adhesion micro tensile tester (SCAμTT) fabricated from IP-S photoresin with two-photon polymerization (TPP) for investigating the mechanics of a single cell-cell junction under defined tensile loading. A major limitation of the platform is the autofluorescence of IP-S, the photoresin for TPP fabrication, which significantly increases background signal and makes fluorescent imaging of stretched cells difficult. In this study, we report the design and fabrication of a new SCAμTT platform that mitigates autofluorescence and demonstrate its capability in imaging a single cell pair as its mutual junction is stretched. By employing a two-material design using IP-S and IP-Visio, a photoresin with reduced autofluorescence, we show a significant reduction in autofluorescence of the platform. Further, by integrating apertures onto the substrate with a gold coating, the influence of autofluorescence on imaging is almost completely mitigated. With this new platform, we demonstrate the ability to image a pair of epithelial cells as they are stretched up to 250% strain, allowing us to observe junction rupture and F-actin retraction while simultaneously recording the accumulation of over 800 kPa of stress in the junction. In conclusion, the platform and methodology presented here can potentially enable detailed investigation of the mechanics of and mechanotransduction in cell-cell junctions and improve the design of other TPP platforms in mechanobiology applications.

Autofluorescence↗
DOE OSTI2018

RF Plasma Polymerization of Orange Oil and Characterization of the Polymer Thin Films

The present study describes an environmentally friendly approach to fabricate hydrocarbon-rich polymer thin films from a bio-renewable precursor, orange oil, cold extracted from orange peels using radio frequency plasma polymerization. The polymer thin films fabricated at different RF power level (10–75 W) were characterized with variable angle spectroscopic ellipsometry, UV–visible spectroscopy, Fourier transform infrared spectroscopy and atomic force microscopy. Optical characterization showed that independent of deposition power films exhibited good transparency (~ 90%) in the visible region and a refractive index of 1.55 at 500 nm. The optical band gap measured around 3.60 eV and falls within the insulating region. The atomic force microscopic images revealed that the surface is pinhole-free in nature and smooth at nanoscale, with average surface roughness dependent on the deposition power. Film hardness increased from 0.50 to 0.78 GPa as applied power increased from 10 to 75 W.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Surface-Modified Cellulose Nanofibers-graft-poly(lactic acid)s Made by Ring-Opening Polymerization of L-Lactide

Highly crystalline cellulose nanofibers with a high density of carboxylate groups only on the surfaces were prepared from both softwood and non-wood cellulose pulp. The preparation method used 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation of native cellulose fibrils in an aqueous TEMPO/NaBr/NaClO system and subsequent postoxidation with NaClO{sub 2} in acetate buffer (pH 4.8). The TEMPO-oxidized cellulose nanofibers (TOCNs) possessed a carboxylate content of 1.7 mmol g{sup −1} and a crystallinity of 67–69% with a crystallite size of ∼3 nm. The TOCNs were used to produce highly crystalline TOCN-graft-poly(lactic acid) (PLA) nanocomposites via ring-opening polymerization of L-lactide in a polar aprotic solvent. Effects of the reaction temperature and the molar ratio of L-lactide to carboxylate surface groups, on the efficiency of surface grafting were investigated to potentially improve the crystallinity and thermal properties of the nanocomposites. The crystallinity of TOCN-g-PLA products was 59–66% greater than the crystallinity of neat PLA.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Synthesis of Carboxyl-Rich Biosorbent by UV-Induced Graft Polymerization Method for High Efficiency Adsorption of Ce{sup 3+} from Aqueous Solution: Activation and Adsorption Mechanism

Developing a cost-effective and highly efficient sorbent for the recovery of rare-earth elements from aqueous solution is still an urgent need. In this study, a novel biosorbent, carboxyl-rich pine bark (CPB), was modified by UV-induced graft polymerization method to increase the carboxyl-containing functional groups and facilitate the adsorption of Ce{sup 3+}. The grafting process was examined by Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM), indicating that high-density carboxyl functional groups are present on the surface of pine bark and the grafting yield of surface polymer brushes reaches up to 128%. Interestingly, the maximum adsorption capacity of Ce{sup 3+} on CPB could reach up to 256.5 mg/g. The adsorption mechanism of Ce{sup 3+} by CPB has been determined by the adsorption models and x-ray photoelectron spectroscopy (XPS), which can be inferred from these results that the high performance of CPB is attributed to the surface coordination between Ce{sup 3+} and hydroxyl or carbonyl groups. This work suggests that engineered surface functional groups of biomass could have an opportunity for the development of high performance rare-earth element adsorbents.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Magnetic Responses of Divinylbenzene-Fe{sub 3}O{sub 4} Composite Film Deposited by Free Radical Polymerization Method

The study reports some novel information on both production and characterization for the poly [DVB/Fe{sub 3}O{sub 4}] composite film deposited by free radical polymerization method. The composite film consists of a combination of organic phase and magnetite nanoparticles. The magnetization behavior of the poly [DVB/Fe{sub 3}O{sub 4}] composite film was analyzed with both vibrating sample magnetometers (VSM) and a technique of electron spin resonance (ESR). It was found that the ESR study performed at room temperature showed the poly [DVB/Fe{sub 3}O{sub 4}] composite film had strong transition of g{sub eff} ∼2.5 (254 mT) due to the Fe{sup 3+} S-state ions. This g{sub eff} value indicated that the composite film behavior was near superparamagnetism. The VSM results also supported the ESR results.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Tetrylenes based on 1,10-phenanthroline-containing diol: the synthesis and application as initiators of ε-caprolactone polymerization

Treatment of 4,7-dichloro-2,9-dimethyl-1,10-phenanthroline with two equivalents of p-tert-butylphenol in the presence of К{sub 2}СО{sub 3} afforded 4,7-di(4-tert-butylphenoxy)-2,9-dimethyl-1,10-phenanthroline (1). Monolithiation of 1 with lithium diisopropylamide followed by treatment with benzophenone resulted in 1-(4,7-bis-p-tert-butylphenoxy-9-methyl-1,10- phenanthrolin-2-yl)methyl-1,1-diphenylethanol (2). 1-(4,7-Bis-p-tert-butylphenoxy-9-hydroxy (diphenyl)methyl-1,10-phenanthrolin-2-yl)-1,1-diphenylethanol (3), a tetradentate ONNO ligand, was prepared analogously from 2. The interaction of 3 with 1 eq. of Lappert’s germylene or stannylene M[N(SiMe{sub 3}){sub 2}]{sub 2} (M = Ge, Sn) led to the corresponding germylene 4 and stannylene 5 in moderate yields. According to {sup 1}Н, {sup 13}С, and {sup 119}Sn NMR spectroscopy data, stannylene 5 is monomeric in solution and the coordination number of tin atom is 4. Tetrylenes 4 and 5 demonstrated high activity as initiators of bulk polymerization of ε-caprolactone which leads to high-molecular-weight polymers with relatively narrow molecular weight distribution.

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

Sterically hindered tetrylenes based on new 1,10-phenanthroline-containing diols: initiators for ε-caprolactone polymerization

Previously unknown tetradentate ONNO-type ligands 1–5 (4,7-di(4-R´-phenoxy)-2,9- di(HOCR{sub 2}CH)-1,10-phenanthrolines (R´ = Me, R–R = –(CH{sub 2}){sub 5}– (1), R = Me (2), R–R = 2,2-adamantylene (3); R´ = But, R–R = –(CH{sub 2}){sub 5}– (4), R = Me (5)) were synthesized by sequential treatment of 2,9-dimethyl-4,7-di(4-R´-phenoxy)-1,10-phenanthrolines 6 (R´ = Me) and 7 (R´ = Bu{sup t}) with excess LDA and appropriate dialkyl ketone. The structure of compound 4 was determined by single-crystal X-ray diffraction. Previously uncharacterized phenanthroline 6 was synthesized by the treatment of 4,7-dichloro-2,9-dimethyl-1,10-phenanthroline with excess p-cresol in the presence of KOH. The reaction of compounds 1–5 with one equivalent of Lappert´s germylene or stannylene, M[N(SiMe{sub 3}){sub 2}]{sub 2} (M = Ge, Sn), gave the corresponding germylenes 8–12 (M = Ge, R´ = Me, R–R = –(CH{sub 2}){sub 5}– (8), R = Me (9), R–R = 2,2-adamantylene (10), R´ = Bu{sup t}, R{sub 2} = –(CH{sub 2}){sub 5}– (11), R = Me (12)) and stannylenes 13–17 (M = Sn, R´ = Me, R–R = –(CH{sub 2}){sub 5}– (13), R = Me (14), R–R = 2,2-adamantylene (15), R´ = Bu{sup t}, R–R = –(CH{sub 2}){sub 5}– (16), R{sub 2} = Me (17)) in satisfactory yields. According to {sup 1}H, {sup 13}C, and {sup 119}Sn NMR data, the synthesized stannylenes are monomeric in solution, and the tin atom has a coordination number of 4. In the series of the compounds under consideration, stannylene 16 proved to be the most active initiator for e-caprolactone polymerization, whereas the germylenes were shown to be inactive in this process.

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

New tetrylenes based on substituted diethylenetriamines: synthesis and use as initiators for ε-caprolactone polymerization

The reactions of 3-benzyl-1,5-ditosyl-1,3,5-triazapentane (1) and 3-benzyl-1,5-dimesityl- 1,3,5-triazapentane (2) with one equivalent of Lappert´s germylene or stannylene (M[N(SiMe{sub 3}){sub 2}]{sub 2}, where M = Ge, Sn) produced germylenes and stannylenes of the general formula PhCH{sub 2}N(CH{sub 2}CH{sub 2}NR){sub 2}M, where M = Ge, R = 4-MeC{sub 6}H{sub 4}SO{sub 2}– (3); 2,4,6-Me{sub 3}C{sub 6}H{sub 2}– (5); M = Sn, R = 4-MeC{sub 6}H{sub 4}SO{sub 2}– (4); 2,4,6-Me{sub 3}C{sub 6}H{sub 2}– (6), in satisfactory yields. According to NMR data ({sup 1}H, {sup 13}C, {sup 119}Sn), stannylenes 4 and 6 are monomeric in solution, and the coordination number of tin is four. The synthesized stannylenes exhibited very high (compound 4) and moderate (compound 6) activity as initiators for bulk polymerization of ε-caprolactone, resulting in the synthesis of high-molecular-weight polymers with relatively narrow molecular-weight distribution. Previously unknown triamine 2 was synthesized by benzylation of HN(CH{sub 2}CH{sub 2}NHMes){sub 2} with benzyl chloride in the presence of K{sub 2}CO{sub 3}.

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

Neodymium dihalide complexes with a tridentate amidinate phosphine oxide ligand: synthesis, structure, and catalytic activity in isoprene polymerization

The deprotonation of amidine 2-[Ph{sub 2}P(O)]C{sub 6}H{sub 4}NHC(Bu{sup t})=N(2,6-Me{sub 2}C{sub 6}H{sub 3}) (1) with BunLi affords lithium amidinate {2-[Ph_2P(O)]C_6H_4NLiC(Bu"t)=N(2,6-Me_2C_6H_3)}2 (2) having a dimeric structure, as demonstrated by X-ray diffraction. New amidinate dihalide complexes {2-[Ph_2P(O)]C_6H_4NC(Bu"t)N(2,6-Me_2C_6H_3)}NdHal{sub 2}(THF){sub 2} (Hal = I (3), Cl (4)) were synthesized by exchange reactions of lithium and potassium amidinates with anhydrous neodymium halides NdHal{sub 3}(THF){sub n} (Hal = I, n = 3.5; Cl, n = 0). The X-ray diffraction studies showed that the new compounds are monomeric and the amidinate ligand is tridentate. Chloride complex 4 involved in the three- and four-component catalyst systems 4–AlR{sub 3}–[Ph3C] [B(C{sub 6}F{sub 5}){sub 4}] (1: 10: 1; AlR{sub 3} = AlBu{sup i} 3, AlMe{sub 3}), 4–AlR{sub 3}–Pr{sup i}OH (1: 10: 10; AlR{sub 3} = AlBu{sup i}{sub 3}, AlMe{sub 3}), and 4–AlR{sub 3}–[Ph{sub 3}C][B(C{sub 6}F{sub 5}){sub 4}]–Pr{sup i}OH (1: 10: 1: 10; AlR{sub 3} = AlBu{sup i}{sub 3}, AlMe{sub 3}) exhibits activity in stereospecific isoprene polymerization and allows the preparation of high-molecular-weight polyisoprene samples with exceptionally high cis-1,4-unit content (up to 99.4%).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

A cell wall-bound anionic peroxidase, PtrPO21, is involved in lignin polymerization in Populus trichocarpa

Class III peroxidases are members of a large plant-specific sequence-heterogeneous protein family. Several sequence-conserved homologs have been associated with lignin polymerization in Arabidopsis thaliana, Oryza sativa, Nicotiana tabacum, Zinnia elegans, Picea abies, and Pinus sylvestris. In Populus trichocarpa, a model species for studies of wood formation, the peroxidases involved in lignin biosynthesis have not yet been identified. To do this, we retrieved sequences of all PtrPOs from Peroxibase and conducted RNA-seq to identify candidates. Transcripts from 42 PtrPOs were detected in stem differentiating xylem (SDX) and four of them are the most xylem-abundant (PtrPO12, PtrPO21, PtrPO42, and PtrPO64). PtrPO21 shows xylem-specific expression similar to that of genes encoding the monolignol biosynthetic enzymes. Using protein cleavage-isotope dilution mass spectrometry, PtrPO21 is detected only in the cell wall fraction and not in the soluble fraction. Downregulated transgenics of PtrPO21 have a lignin reduction of ~20% with subunit composition (S/G ratio) similar to wild type. The transgenics show a growth reduction and reddish color of stem wood. The modulus of elasticity (MOE) of the stems of the downregulated PtrPO21-line 8 can be reduced to ~60% of wild type. Differentially expressed gene (DEG) analysis of PtrPO21 downregulated transgenics identified a significant overexpression of PtPrx35, suggesting a compensatory effect within the peroxidase family. No significant changes in the expression of the 49 P. trichocarpa laccases (PtrLACs) were observed.

09 BIOMASS FUELS↗
DOE OSTI2023

Controlled catalyst-transfer polymerization in graphene nanoribbon synthesis

Exercising direct control over the unusual electronic structures arising from quantum confinement effects in graphene nanoribbons (GNRs) is intimately linked to geometric boundary conditions imposed by the structure of the ribbon. Besides composition and position of substitutional dopant atoms, the symmetry of the unit cell, width, length, and termination of a GNR govern its electronic structure. Here, we present a rational design that integrates each of these interdependent variables within a modular bottom-up synthesis. Our hybrid chemical approach relies on a catalyst-transfer polymerization that establishes excellent control over length, width, and end groups. Complemented by a surface-assisted cyclodehydrogenation step, uniquely enabled by matrix-assisted direct (MAD) transfer protocols, geometry and functional handles encoded in a polymer template are faithfully mapped onto the structure of the corresponding GNR. Bond-resolved scanning tunneling microscopy (BRSTM) and spectroscopy (STS) validate the robust correlation between polymer template design and GNR electronic structure.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Polymeric ionic liquids containing copper(I) and copper(II) ions as gas chromatographic stationary phases for olefin separations

Copper(I) ions (Cu + ) are used in olefin separations due to their olefin complexing ability and low cost, but their instability in the presence of water and gases limits their widespread use. Ionic liquids (ILs) have emerged as stabilizers of Cu + ions and prevent their degradation, providing high olefin separation efficiency. There is limited understanding into the role that polymeric ionic liquids (PILs), which possess similar structural characteristics to ILs, have on Cu + ion-olefin interactions. Moreover, copper ions with diverse oxidation states, including Cu + and Cu 2+ ions, have been rarely employed for olefin separations. In this study, gas chromatography (GC) is used to investigate the interaction strength of olefins to stationary phases composed of the 1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C 6 MIM + ][NTf 2 – ]) IL and the poly(1-hexyl-3-vinylimidazolium [NTf 2 – ]) (poly([C 6 VIM + ][NTf 2 – ])) PIL containing monovalent and divalent copper salts (i.e., [Cu + ][NTf 2 – ] and [Cu 2+ ]2[NTf 2 – ]). The chromatographic retention of alkenes, alkynes, dienes, and aromatic compounds was examined. Incorporation of the [Cu 2+ ]2[NTf 2 – ] salt into a stationary phase comprised of poly(dimethylsiloxane) resulted in strong retention of olefins, while its addition to the [C 6 MIM + ][NTf 2 – ] IL and poly([C 6 VIM + ][NTf 2 – ]) PIL allowed for the interaction strength to be modulated. Olefins exhibited greater affinities toward IL and PIL stationary phases containing the [Cu 2+ ]2[NTf 2 – ] salt compared to those with the [Cu + ][NTf 2 – ] salt. Elimination of water from both copper salts was observed to be an important factor in promoting olefin interactions, as evidenced by increased olefin retention upon exposure of the stationary phases to high temperatures. Furthermore, to evaluate the long-term thermal stability of the stationary phase, chromatographic retention of probes was measured on the [Cu 2+ ]2[NTf 2 – ]/[C 6 MIM + ][NTf 2 – ] IL stationary phase after its exposure to helium at a temperature of 110°C.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Calcium carbonate formation on mica supported extracellular polymeric substance produced by Rhodococcus opacus

Extracellular polymeric substance (EPS) extracted from Rhodococcus opacus bacterial strain was used as a matrix for calcium carbonate precipitation using the vapour diffusion method. The total exopolymer and water-soluble exopolymer fraction of different concentrations were spread on the mica surface by the spin-coating method. The obtained layers were characterized using the atomic force microscopy measurement and XPS analysis. The effects of polymer concentration, initial pH of calcium chloride solution and precipitation time on the obtained crystals properties were investigated. Raman spectroscopy and scanning electron microscopy were used to characterize the precipitated minerals. It was found that the type of precipitated CaCO{sub 3} polymorph and the crystal size depend on the kind of EPS fraction. The obtained results indicates that the water soluble fraction favours vaterite dissolution and calcite growth, whereas the total EPS stabilizes vaterite and this effect is stronger at basic pH. It seems to be due to different contents of the functional group of EPS fractions. - Highlights: • CaCO{sub 3} crystal size and polymorph can be controlled by EPS substance obtained from R. opacus. • The water soluble fraction favours vaterite dissolution and calcite growth. • The total EPS stabilizes vaterite. • This effect is stronger at basic pH.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Pressure-assisted thermal sterilization of avocado puree in high barrier polymeric packaging

The aim of this study was to examine the influence of pressure-assisted thermal sterilization (PATS) on properties of polymeric packaging and packaged avocado puree. High pressure of 600 MPa and initial vessel temperature of 90 °C were used over 5 min processing time. We used two high barrier film pouches: Film A-(PE/PA6//EVOH//PA6/PE) and film B-(AlO x -coated PET//AlO x -coated PET//PA//CPP). Oxygen transmission rates (OTR) changed from 0.16 ± 0.07 to 3.24 ± 0.52 cm 3 /m 2 .day for film A after processing while OTRs were not detected for film B. Water vapor transmission rates (WVTR) changed from 3.72 ± 0.06 to 4.97 ± 0.14 g/m 2 .day for film A and 0.11 ± 0.02 to 0.62 ± 0.0.6 g/m 2 .day for film B. The dissolved oxygen in packaged avocado puree reduced from 21% to 3% after PATS for both films. Reduced oxygen level in packaged avocado may help extend its shelf life. Dielectric properties and X-ray diffraction helped explain PATS induced changes in film barrier properties. The total chlorophyll, greenness, and lightness decreased significantly (p < 0.05) after PATS. The thiobarbituric acid activity reduced after PATS. PATS showed potential to produced shelf-stable avocado puree; however, shelf-life studies are needed to further develop PATS process.

42 ENGINEERING↗
DOE OSTI2023

Stretchable and wearable polymeric heaters and strain sensors fabricated using liquid metals

Wearable electronic devices (WEDs) are receiving significant attention because of the increasing interest in soft robotics, electronic skin, and wearable sensors. Liquid metals (LMs) are compelling for WEDs owing to their metallic conductivity, fluidic nature, and low toxicity. For this study, we fabricated stretchable and soft WEDs using LM (eutectic gallium-indium alloy) wires (LMWs) patterned via force wetting through custom-made stencils on an elastic substrate. LMWs can generate thermal energy via Joule heating upon current application and deliver it to the substrate, resulting in wearable polymeric heaters. The LM mixed with carbonyl iron particles (CIPs) can also be patterned while preserving fluidic behavior. The degree of thermal energy generated through the LMWs can be manipulated as a function of the CIP concentration in the LM and geometrical factors of the electrode patterns, i.e., width and length. An elastic film patterned with LMWs attached to the human body exhibits changes in the effective electrical resistance depending on applied strain, demonstrating potential as a wearable strain sensor. This LM utilized WED that can generate thermal energy upon current application through the LMWs and detect the bodily motion has significant potential for application in wearable thermotherapy, electronic skin, and soft sensors.

47 OTHER INSTRUMENTATION↗