Folding Cycle Research Articles

Constructing bilayer heterogeneous organogel electrolytes of Lewis acidic/basic polymers to suppress self-discharge of supercapacitors

Flexible supercapacitors with fast charging rate, long cyclic lifetime and high power density, but often suffer from their rapid self-discharge process, which remains a big challenge for their widely commercial application. Here, we for the first time report a bilayer heterogeneous organogel electrolyte (BHOE) consisting of a layer of Lewis acidic polymer (LAP) and a layer of Lewis basic polymer (LBP), to develop high-performance flexible supercapacitors with slow self-discharge process. The existing strong coordination interaction between the charged LAP (or LBP) and its counter anions (or cations) can effectively restrict the diffusion of ions accumulated on/in the electrodes into or throughout the bilayer electrolyte, which endowed the charged BHOE-based supercapacitor with slow self-discharge time (9.7 h) from its open-circuit voltage to the half, more than ten times longer than those (0.9 h) of devices based homogeneous LAP or LBP electrolytes. Furthermore, the BHOE-based supercapacitor possessed high capacitance retention up to 95 % after thousands of folding cycles, suggesting excellent mechanical flexibility. This study provides a novel strategy to build high-performance flexible supercapacitors with slow self-discharge, which is great meaningful for their practical application in the near future.

Flexible Finely and Directly Patternable Liquid Metal Electrodes via Selective Surface Wetting Technique

Eutectic gallium–indium (EGaIn) is an ideal material for preparing flexible electrodes, but its high surface tension poses a challenge during deposition and patterning. Herein, we propose a laser-induced selective surface wetting technique (SSWT) to enable the facile and straightforward fabrication of flexible finely and directly patternable EGaIn liquid metal electrodes. Our proposed technique selectively controls the wettability of EGaIn by establishing a perfluorinated self-assembled monolayer on a zinc oxide nanorod array to impart superhydrophobicity and then inducing specific sites on the hydrophilized surface by ultraviolet (UV) pulsed laser ablation, thereby enabling fine patterning (linewidth, ~50 μm). Surface analysis of the effect of laser ablation was also performed to elucidate the mechanism of SSWT. The patterned EGaIn liquid metal electrode fabricated by SSWT exhibited superior flexibility, with a resistance change (ΔR/R0) of only 18.6% compared with a Ag thin film electrode, which showed a dramatic increase in ΔR/R0 to nearly 500% after 50,000 folding cycles at a peak strain of 2.5%. The simple and easily implementable liquid metal patterning technique proposed in this study may potentially be applied in the field of wearable and stretchable electronics, which requires extreme flexibility.

Molecular Dynamics Mappings of the CCT/TRiC Complex-Mediated Protein Folding Cycle Using Diffracted X-ray Tracking.

The CCT/TRiC complex is a type II chaperonin that undergoes ATP-driven conformational changes during its functional cycle. Structural studies have provided valuable insights into the mechanism of this process, but real-time dynamics analyses of mammalian type II chaperonins are still scarce. We used diffracted X-ray tracking (DXT) to investigate the intramolecular dynamics of the CCT complex. We focused on three surface-exposed loop regions of the CCT1 subunit: the loop regions of the equatorial domain (E domain), the E and intermediate domain (I domain) juncture near the ATP-binding region, and the apical domain (A domain). Our results showed that the CCT1 subunit predominantly displayed rotational motion, with larger mean square displacement (MSD) values for twist (χ) angles compared with tilt (θ) angles. Nucleotide binding had a significant impact on the dynamics. In the absence of nucleotides, the region between the E and I domain juncture could act as a pivotal axis, allowing for greater motion of the E domain and A domain. In the presence of nucleotides, the nucleotides could wedge into the ATP-binding region, weakening the role of the region between the E and I domain juncture as the rotational axis and causing the CCT complex to adopt a more compact structure. This led to less expanded MSD curves for the E domain and A domain compared with nucleotide-absent conditions. This change may help to stabilize the functional conformation during substrate binding. This study is the first to use DXT to probe the real-time molecular dynamics of mammalian type II chaperonins at the millisecond level. Our findings provide new insights into the complex dynamics of chaperonins and their role in the functional folding cycle.

Bamboo Pulp Toughening Poly (Lactic Acid) Composite Using Reactive Epoxy Resin.

A novel poly (lactic acid) (PLA) composite with excellent mechanical properties, toughness, thermal stability, and water resistance was developed using a reactive melt-blending technique. PLA was melt mixed with epoxy resin (EPOXY) and bamboo pulp (PULP) to improve its reaction and mechanical properties. FTIR analysis confirmed the successful reaction of the PLA/EPOXY/PULP composites; the epoxy groups of EPOXY reacted with the -COOH groups of PLA and the -OH groups of PULP. The PLA/EPOXY/PULP5 composite showed a high tensile strength (67 MPa) and high toughness of 762 folding cycles, whereas the highest tensile strength was 77 MPa in the PLA/EPOXY5/PULP20 sample. SEM images presented a gap between the PLA and PULP; gap size decreased with the addition of EPOXY. The Tg of the PLA decreased with the EPOXY plasticizer effect, whereas the Tm did not significantly change. PULP induced crystallinity and increased Vicat softening of the PLA/PULP and PLA/EPOXY/PULP composites. The EPOXY reaction of the PLA/PULP composites improved their tensile properties, toughness, thermal stability, and water resistance.

Multilayer Ti3C2Tx MXene/graphene oxide/carbon fiber fabric/thermoplastic polyurethane composite for improved mechanical and electromagnetic interference shielding performance

The development of flexible electronics has placed higher demands on electromagnetic interference (EMI) shielding materials, especially in terms of mechanical properties. Herein, a novel composite with excellent mechanical and EMI shielding properties was developed. The electrohydrodynamic atomization deposition approach was used to deposit Ti3C2Tx MXene and graphene oxide (GO) nanosheets on carbon fiber fabric (CFf) surface, then they were assembled layer by layer with thermoplastic polyurethane (TPU) and thermoformed at high temperature to obtain MG/f-CFf/TPU composite. When the MXene/GO content increases, the mechanical performance of the composite is improved, mainly owing to the formation of chemical bonds and the presence of mechanical interlocking and van der Waals forces. Specifically, the tensile strength and interlaminar shear strength of the composite reach 140.98 MPa and 54.67 MPa, increasing by 72.45 % and 52.92 %, respectively. Benefitting from the unique lamellar structure, the maximum EMI-SE of MG/f-CFf/TPU composite is 38.29 dB. Besides, the MG/f-CFf/TPU composite also displays outstanding EMI-SE stability after 3000 times folding cycles. The flexible MG/f-CFf/TPU composite may provide more guidelines for the design of next-generation flexible EMI shielding materials.

Electrohydrodynamic Printed PEDOT:PSS/Graphene/PVA Circuits for Sustainable and Foldable Electronics

AbstractThe generation of electronic waste (e‐waste) poses a significant environmental challenge, necessitating strategies to extend electronics’ lifespan and incorporate eco‐friendly materials to enable their rapid degradation after disposal. Foldable electronics utilizing eco‐friendly materials offer enhanced durability during operation and degradability at the end of their life cycle. However, ensuring robust physical adhesion between electrodes/circuits and substrates during the folding process remains a challenge, leading to interface delamination and electronic failure. In this study, electrohydrodynamic (EHD) printing is employed as a cost‐effective method to fabricate the eco‐friendly foldable electronics by printing PEDOT:PSS/graphene composite circuits onto polyvinyl alcohol (PVA) films. The morphology and electrical properties of the printed patterns using inks with varying graphene and PEDOT:PSS weight ratios under different printing conditions are investigated. The foldability of the printed electronics is demonstrated, showing minimal resistance variation and stable electronic response even after four folds (16 layers) and hundreds of folding and unfolding cycles. Additionally, the application of printed PEDOT:PSS/graphene circuit is presented as a resistive temperature sensor for monitoring body temperature and respiration behavior. Furthermore, the transient features and degradation of the PEDOT:PSS/graphene/PVA based foldable electronics are explored, highlighting the potential promise as transient electronics in reducing electronic waste.

A Zpr1 co-chaperone mediates folding of eukaryotic translation elongation factor 1A via a GTPase cycle

General protein folding is mediated by chaperones that utilize ATP hydrolysis to regulate client binding and release. Zinc-finger protein 1 (Zpr1) is an essential ATP-independent chaperone dedicated to the biogenesis of eukaryotic translation elongation factor 1A (eEF1A), a highly abundant GTP-binding protein. How Zpr1-mediated folding is regulated to ensure rapid Zpr1 recycling remains an unanswered question. Here, we use yeast genetics and microscopy analysis, biochemical reconstitution, and structural modeling to reveal that folding of eEF1A by Zpr1 requires GTP hydrolysis. Furthermore, we identify the highly conserved altered inheritance of mitochondria 29 (Aim29) protein as a Zpr1 co-chaperone that recognizes eEF1A in the GTP-bound, pre-hydrolysis conformation. This interaction dampens Zpr1⋅eEF1A GTPase activity and facilitates client exit from the folding cycle. Our work reveals that a bespoke ATP-independent chaperone system has mechanistic similarity to ATPase chaperones but unexpectedly relies on client GTP hydrolysis to regulate the chaperone-client interaction.

Liquid metal assisted fabrication of MXene-based films: Toward superior electromagnetic interference shielding and thermal management

The development of thin and flexible films that possess both electromagnetic interference (EMI) shielding and thermal management capabilities has always been an intriguing pursuit, but itisnevertheless a crucialproblemtoaddress. Inspired by the deformability of liquid metal (LM) and film forming capacity of MXene, here we present a series of ternary compositing films prepared via cellulose nanofiber (CNF) assisted vacuum filtration technology. Originating from the highly conductive LM/MXene network, the MLMC film presents a maximum EMI shielding effectiness (EMI SE) of 78 dB at a tiny thickness of 45 μm, together with a high specific EMI SE of 3046 dB mm−1. Meanwhile, these compositing films also deliver excellent flexibility and mechanical reliability, showing no obvious decline in EMI shielding performance even after 1000 bending and 500 folding cycles, respectively. Moreover, notable anisotropic thermal conductive property was successfully achieved, allowing for a highly desirable in-plane thermal conductivity of 7.8 W m−1 K−1. This accomplishment also yielded an exceptional electro-thermal conversion capacity, enabling efficient low-voltage (3 V) heating capabilities. These captivating features are expected to greatly drive the widespread adoption of LM-based films in future flexible electronic and wearable technologies.

Interface‐Anchored Covalent Organic Frameworks@Amino‐Modified Ti3C2Tx MXene on Nylon 6 Film for High‐Performance Deformable Supercapacitors

AbstractDesigning deformable supercapacitors (D‐SCs) that have robust skeleton and smoothly active channels for charges kinetic migration and faradic storage are highly crucial for wearable systems. Here, we develop the high‐performance D‐SCs made of the covalent organic frameworks(COF)@amino‐modified Ti3C2Tx deposited on decorated nylon 6 (DPA) film (COF@N‐Ti3C2Tx/DPA) via layer‐by‐layer fabrication. The hierarchical COF@N‐Ti3C2Tx/DPA exhibits admirable specific capacitance, rate performance and cycling stability in three‐electrode system due to the superior H+ storage property and large interfacial charge transfer clarified by density functional theory calculations. Additionally, the solid‐state D‐SCs deliver favourable energy density and practical energy‐supply applications. Particularly, the solid‐state D‐SCs present high deformable stabilities, with regard to 80.7, 80.6 and 83.4 % capacitance retention after 5000 bending cycles, 2000 stretching cycles and 5000 folding cycles, separately.

Interface-Anchored Covalent Organic Frameworks@Amino-Modified Ti3 C2 Tx MXene on Nylon 6 Film for High-Performance Deformable Supercapacitors.

Designing deformable supercapacitors (D-SCs) that have robust skeleton and smoothly active channels for charges kinetic migration and faradic storage are highly crucial for wearable systems. Here, we develop the high-performance D-SCs made of the covalent organic frameworks(COF)@amino-modified Ti3 C2 Tx deposited on decorated nylon 6 (DPA) film (COF@N-Ti3 C2 Tx /DPA) via layer-by-layer fabrication. The hierarchical COF@N-Ti3 C2 Tx /DPA exhibits admirable specific capacitance, rate performance and cycling stability in three-electrode system due to the superior H+ storage property and large interfacial charge transfer clarified by density functional theory calculations. Additionally, the solid-state D-SCs deliver favourable energy density and practical energy-supply applications. Particularly, the solid-state D-SCs present high deformable stabilities, with regard to 80.7, 80.6 and 83.4 % capacitance retention after 5000 bending cycles, 2000 stretching cycles and 5000 folding cycles, separately.

66‐4: Late‐News Paper: Z Type Multi‐Foldable AMOLED for High Durability and Superior Foldability

In this paper, we have developed Z‐type Multi‐Foldable AMOLED (ZMFA) for high durability and foldability. These properties are achieved by optimized Neutral plane of module stack. We also optimized module stack and layer materials for durability. In this paper, We will show panel characteristic of 8.97inch multi‐foldable (Z type) displays which 200k in & out folding cycles with inner folding 1.5R and Outer folding 4.0R Also, dent 6H@300gf and pen tracing (1.4 km@ 200gf)

Hsp90 mutants with distinct defects provide novel insights into cochaperone regulation of the folding cycle.

Molecular chaperones play a key role in maintaining proteostasis and cellular health. The abundant, essential, cytosolic Hsp90 (Heat shock protein, 90 kDa) facilitates the folding and activation of hundreds of newly synthesized or misfolded client proteins in an ATP-dependent folding pathway. In a simplified model, Hsp70 first helps load client onto Hsp90, ATP binding results in conformational changes in Hsp90 that result in the closed complex, and then less defined events result in nucleotide hydrolysis, client release and return to the open state. Cochaperones bind and assist Hsp90 during this process. We previously identified a series of yeast Hsp90 mutants that appear to disrupt either the 'loading', 'closing' or 'reopening' events, and showed that the mutants had differing effects on activity of some clients. Here we used those mutants to dissect Hsp90 and cochaperone interactions. Overexpression or deletion of HCH1 had dramatically opposing effects on the growth of cells expressing different mutants, with a phenotypic shift coinciding with formation of the closed conformation. Hch1 appears to destabilize Hsp90-nucleotide interaction, hindering formation of the closed conformation, whereas Cpr6 counters the effects of Hch1 by stabilizing the closed conformation. Hch1 and the homologous Aha1 share some functions, but the role of Hch1 in inhibiting progression through the early stages of the folding cycle is unique. Sensitivity to the Hsp90 inhibitor NVP-AUY922 also correlates with the conformational cycle, with mutants defective in the loading phase being most sensitive and those defective in the reopening phase being most resistant to the drug. Overall, our results indicate that the timing of transition into and out of the closed conformation is tightly regulated by cochaperones. Further analysis will help elucidate additional steps required for progression through the Hsp90 folding cycle and may lead to new strategies for modulating Hsp90 function.

CHIP: A Co-chaperone for Degradation by the Proteasome and Lysosome.

Protein homeostasis relies on a balance between protein folding and protein degradation. Molecular chaperones like Hsp70 and Hsp90 fulfill well-defined roles in protein folding and conformational stability via ATP-dependent reaction cycles. These folding cycles are controlled by associations with a cohort of non-client protein co-chaperones, such as Hop, p23, and Aha1. Pro-folding co-chaperones facilitate the transit of the client protein through the chaperone-mediated folding process. However, chaperones are also involved in proteasomal and lysosomal degradation of client proteins. Like folding complexes, the ability of chaperones to mediate protein degradation is regulated by co-chaperones, such as the C-terminal Hsp70-binding protein (CHIP/STUB1). CHIP binds to Hsp70 and Hsp90 chaperones through its tetratricopeptide repeat (TPR) domain and functions as an E3 ubiquitin ligase using a modified RING finger domain (U-box). This unique combination of domains effectively allows CHIP to network chaperone complexes to the ubiquitin-proteasome and autophagosome-lysosome systems. This chapter reviews the current understanding of CHIP as a co-chaperone that switches Hsp70/Hsp90 chaperone complexes from protein folding to protein degradation.

Nucleotide Exchange Factors for Hsp70 Molecular Chaperones: GrpE, Hsp110/Grp170, HspBP1/Sil1, and BAG Domain Proteins.

Molecular chaperones of the Hsp70 family are key components of the cellular protein-folding machinery. Substrate folding is accomplished by iterative cycles of ATP binding, hydrolysis, and release. The ATPase activity of Hsp70 is regulated by two main classes of cochaperones: J-domain proteins stimulate ATPase hydrolysis by Hsp70, while nucleotide exchange factors (NEFs) facilitate the conversion from the ADP-bound to the ATP-bound state, thus closing the chaperone folding cycle. NEF function can additionally be antagonized by ADP dissociation inhibitors. Beginning with the discovery of the prototypical bacterial NEF, GrpE, a large diversity of nucleotide exchange factors for Hsp70 have been identified, connecting it to a multitude of cellular processes in the eukaryotic cell. Here we review recent advances toward structure and function of nucleotide exchange factors from the Hsp110/Grp170, HspBP1/Sil1, and BAG domain protein families and discuss how these cochaperones connect protein folding with cellular quality control and degradation pathways.

Selective involvement of UGGT variant: UGGT2 in protecting mouse embryonic fibroblasts from saturated lipid-induced ER stress

Secretory proteins and lipids are biosynthesized in the endoplasmic reticulum (ER). The "protein quality control" system (PQC) monitors glycoprotein folding and supports the elimination of terminally misfolded polypeptides. A key component of the PQC system is Uridine diphosphate glucose:glycoprotein glucosyltransferase 1 (UGGT1). UGGT1 re-glucosylates unfolded glycoproteins, to enable the re-entry in the protein-folding cycle and impede the aggregation of misfolded glycoproteins. In contrast, a complementary "lipid quality control" (LQC) system that maintains lipid homeostasis remains elusive. Here, we demonstrate that cytotoxic phosphatidic acid derivatives with saturated fatty acyl chains are one of the physiological substrates of UGGT2, an isoform of UGGT1. UGGT2 produces lipid raft-resident phosphatidylglucoside regulating autophagy. Under the disruption of lipid metabolism and hypoxic conditions, UGGT2 inhibits PERK-ATF4-CHOP-mediated apoptosis in mouse embryonic fibroblasts. Moreover, the susceptibility of UGGT2 KO mice to high-fat diet-induced obesity is elevated. We propose that UGGT2 is an ER-localized LQC component that mitigates saturated lipid-associated ER stress via lipid glucosylation.

Nanocellulose-Linked MXene/Polyaniline Aerogel Films for Flexible Supercapacitors.

In the development of energy supply systems for smart wearable devices, supercapacitors stand out owing to their ability of quick and efficient energy supply. However, their application is limited due to their low energy density and poor mechanical energy. Herein, a strategy for the preparation of flexible supercapacitors is reported, which is based on the fabrication of aerogel films by simultaneously utilising cellulose nanofiber (CNFs) as an MXene intercalation material and polyaniline (PANI) as a template material. CNFs, which can form hydrogen-bonded networks, enhance the mechanical properties of MXene from 44.25 to 119.56 MPa, and the high electron transport properties of PANI endow MXene with a capacitance of 327 F g-1 and a resistance of 0.23 Ω. Furthermore, the combination of CNFs and PANI enables a 71.6% capacitance retention after 3000 charge/discharge and 500 folding cycles. This work provides a new platform for the development of flexible supercapacitors.

Sandwiched Structure Design for Perovskite Solar Cells with Improved Folding and Environmental Stability

Foldable perovskite solar cells (PSCs) have promising applications in self‐powered wearable and portable electronic devices. However, the folding stability requires further improvement through mitigating the strain in brittle layers under folding deformation. Herein, sandwich‐structured PSCs (SS‐PSCs) are constructed by coating a protection layer at the back of the device, to tune the neutral plane (NP) place into the brittle perovskite films. To accurately regulating the NP place, the effect of protective layer thickness on the strain distribution in PSCs is simulated. The SS‐PSCs are experimentally prepared using Al2O3/polyethylene terephthalate (PET) protection layer with optimum thickness, combined with ultrathin silver foldable electrodes. Benefitting from the water‐resisting Al2O3/PET, the SS‐PSCs demonstrate high environment stability which maintains 85.1% of original efficiency after 700 h in humidity of 50% ± 10%. More importantly, the SS‐PSCs exhibit excellent mechanical stability, which maintains >90% of the initial efficiency after bending with 4000 cycles at radius of 0.2 mm, and even 67.2% of the initial efficiency after 50 direct folding cycles. As far as it is known, it is one of the best mechanical stable devices. The findings pave the way for realizing not only foldable PSCs but also other foldable optoelectronic devices, such as sensors and organic light emitting devices.

Toward actuation of Kresling pattern-based origami robots

This work investigates the technical requirement for the actuation of the bi-directional rotational motion (BRM) of engineering-material-based non-rigid origami robots. While the vast majority of previously published results have focused on paper-based origami structures driven by translation-motion, polypropylene (PP) is implemented in this research to investigate its ability to respond to engineering requirements according to BRM. Following this objective, three experiments are proposed to identify the technical performances of PP-based origami and kirigami robots based on Kresling pattern. First, the stabilization test shows that two hundred full folding cycles are required to reach a repeatable mechanical response. Second, the BRM test characterizes the various mechanical performances of both origami and kirigami structure: the PP-based origami outperforms existing structures in the literature. Third, the actuation test shows that the actuation mechanical requirements can be described using three key parameters: the required torque for folding, the shape-blocking stiffness, and the bistable portion. Finally, in order to support the development of PP-based origami/kirigami robots, a ‘Bar and Hinge’ reduced-order model is implemented for the description of the nonlinear hysteretic behavior and bistability. This method constitutes a useful tool for the design of highly nonlinear/bistable engineering structures based on PP origami and kirigami.

Ultra-flexible and transparent electrodes with controllable crack length via metal–polymer hybrid nanostructure

• A method for fabricating a super-flexible transparent electrode. • The flexible electrodes exhibited excellent flexibility. • Under severe cyclic folding fatigue a peak strain of 2.5% was observed. • A folding-cycle count of 100,000 was obtained. • The good performance was due to the metal–polymer hybrid nanostructure. We propose a method for improving the flexibility of transparent electrodes through a mechanism that effectively reduces the crack length under cyclic folding fatigue. Our proposed method is based on the use of a metal–polymer hybrid (MPH) nanostructure composed of indium tin oxide (ITO), Ag, and a fluoropolymer, which are commercially available materials widely used in the display-panel manufacturing industry. For flexible electrodes wherein the MPH nanostructure was adjusted using Ag sputtering powers within the range of 20–50 W, the changes in the resistance after 100,000 folding cycles with a peak strain of 2.5% were 4.57–17.9%, whereas those in the case of the ITO/Ag/ITO (IAI) thin-film electrode, i.e., without the MPH nanostructure, increased dramatically to 11,228%. Through the introduction of the MPH nanostructure, the crack length was significantly reduced to 8.76–88.1 μm compared to that of the IAI thin-film electrode (> 945 μm), and also became controllable through the adjustment of the number density of the MPH nanostructure.

Fabrication and properties of thermally conductive adhesive tapes containing multilayer graphene patterns

In order to overcome the low thermal conductivity of pressure-sensitive adhesives (PSAs), multilayer graphene (MLG) pattern embedded PSA tapes (g-PSAs tapes) were fabricated in this study. First, an acrylic copolymer was synthesized and used as a component of a PSA. The glass transition temperature of the PSA and peel strength of the neat PSA tape were determined as −30 °C and 792 ± 14 gf/25 mm, respectively. Next, g-PSA tapes were fabricated by laminating an uncrosslinked PSA tape onto MLG patterns on a PET film followed by curing. The MLG content of the g-PSA tapes was adjusted with the size of MLG patterns fabricated by using metal masks with various opening sizes. Unlike the neat PSA tape, the peel strength of the g-PSA tapes fluctuated during peeling because of the delamination of the graphene layers. The in-plane thermal conductivity of the stacked g-PSA-2 tape with a graphene content of 21.4 vol% was measured to be 5.51 Wm−1K−1. The mechanical durability of the g-PSA-1 and g-PSA-2 tapes was also measured through a folding test and no delamination of the tapes was observed after 10000 folding cycles.