Adaptive advantages of restorative RNA editing in fungi for resolving survival-reproduction trade-offs.

RNA editing in various organisms commonly restores RNA sequences to their ancestral state, but its adaptive advantages are debated. In fungi, restorative editing corrects premature stop codons in pseudogenes specifically during sexual reproduction. We characterized 71 pseudogenes and their restorative editing in Fusarium graminearum, demonstrating that restorative editing of 16 pseudogenes is crucial for germ tissue development in fruiting bodies. Our results also revealed that the emergence of premature stop codons is facilitated by restorative editing and that premature stop codons corrected by restorative editing are selectively favored over ancestral amino acid codons. Furthermore, we found that ancestral versions of pseudogenes have antagonistic effects on reproduction and survival. Restorative editing eliminates the survival costs of reproduction caused by antagonistic pleiotropy and provides a selective advantage in fungi. Our findings highlight the importance of restorative editing in the evolution of fungal complex multicellularity and provide empirical evidence that restorative editing serves as an adaptive mechanism enabling the resolution of genetic trade-offs.

Polysomnography scoring-related training and quantitative assessment for improving interscorer agreement.

STUDY OBJECTIVES: To efficiently improve the scoring competency of scorers with varying levels of experience across regions in Taiwan, we developed a training program with a cloud-based polysomnography scoring platform to evaluate and improve interscorer agreement. METHODS: A total of 70 scorers from 34 sleep centers in Taiwan (job tenure: 0.5-39.0 years) completed a scoring test. All scorers scored a 742-epoch (30 s/epoch) overnight polysomnography recording of a patient with a moderate apnea-hypopnea index. Subsequently, 8 scoring experts delivered 8 interactive online lectures (each lasting 30 minutes). The training program included identifying scoring weaknesses, highlighting the latest scoring rules, and providing physicians' perspectives. Afterward, the scorers completed the second scoring test on the same participant. Changes in agreement from the first to second scoring test were identified. Sleep staging, sleep parameters, and respiratory events were considered for evaluating scoring agreement. RESULTS: The scorers' agreement in overall sleep stage scoring significantly increased from 74.6 to 82.3% (median score). The proportion of scorers with an agreement of ≥ 80% increased from 20.0% (14/70) to 58.6% (41/70) after the online training program. In addition, the scorers' agreement in overall respiratory-event scoring increased to 88.8% (median score) after training. The scorers with a job tenure of 2.0-4.9 years exhibited the highest level of improvement in overall sleep staging (their median agreement increased from 72.8 to 84.9%; P < .001). CONCLUSIONS: Our interactive online training program efficiently targeted the scorers' scoring weaknesses identified in the first scoring test, leading to substantial improvements in scoring proficiency. CITATION: Liao Y-S, Wu M-C, Li C-X, Lin W-K, Lin C-Y, Liang S-F. Polysomnography scoring-related training and quantitative assessment for improving interscorer agreement. J Clin Sleep Med. 2024;20(2):271-278.

End block dynamics in unentangled polymers by dielectric spectroscopy.

Dielectric spectroscopy measures the dynamics of polymer melts over a broad frequency range. Developing a theory for the spectral shape can extend the analysis of dielectric spectra beyond determining relaxation times from the peak maxima and adds physical meaning to shape parameters determined with empirical fit functions. Toward this goal, we use the experimental results on unentangled poly(isoprene), and unentangled poly(butylene oxide), polymer melts, to test whether the concept of end blocks could be one reason for the Rouse model deviating from experimental data. These end blocks have been suggested by simulations and neutron spin echo spectroscopy and are a consequence of the monomeric friction coefficient depending on the position of the bead in the chain. The concept of an end block is an approximation which partitions the chain in a middle and two end blocks to avoid overparameterization by a continuous position dependent change of the friction parameter. Analysis of dielectric spectra shows that the deviations of the calculated from the experimental normal mode cannot be related to the end block relaxation. However, the results do not contradict an end block hiding below the segmental relaxation peak. It seems that the results are compatible with an end block being the specific part of the sub-Rouse chain interpretation close to the chain ends.

Uniqueness of Relaxation Times Determined by Dielectric Spectroscopy.

Dielectric spectroscopy (DS) is extremely powerful to study molecular dynamics, be-cause of the very broad frequency range. Often multiple processes superimpose resulting in spec-tra that expand over several orders of magnitude, with some of the contributions partially hidden. For illustration, we selected two examples, (i) normal mode of high molar mass polymers partial-ly hidden by conductivity and polarization and (ii) contour length fluctuations partially hidden by reptation using the well-studied polyisoprene melts as example. The intuitive approach to de-scribe experimental spectra and to extract relaxation times is the addition of two or more model functions. Here, we use the empirical Havriliak-Negami (HN) function to illustrate the ambigui-ty of the extracted relaxation time, despite an excellent agreement of the fit with experimental data. We show that there are an infinite number of solutions for which a perfect description of experimental data can be achieved. However, a simple mathematical relationship indicates uniqueness of the pairs of the relaxation strength and relaxation time. Sacrificing the absolute value of the relaxation time enables to find the temperature dependence of the parameters with a high accuracy. For the specific cases studied here, the time temperature superposition (TTS) is very useful to confirm the principle. However, the derivation is not based on a specific tempera-ture dependence, hence, independent from the TTS. We compare new and traditional approaches and find the same trend for the temperature dependence. The important advantage of the new technology is the knowledge of the accuracy of the relaxation times. Relaxation times deter-mined from data for which the peak is clearly visible are the same within the experimental accu-racy for traditional and new technology. However, for data where a dominant process hides the peak substantial deviations can be observed. We conclude that the new approach is particularly helpful for cases in which relaxation times need to be determined without having access to the associated peak position.

Assessing the Effects of Ozonation on the Concentrations of Personal Care Products and Acute Toxicity in Sludges of Wastewater Treatment Plants.

The aim of this study was to understand the distribution of the personal care products nonylphenol (NP), triclosan (TCS), benzophenone-3 (BP-3), and caffeine in the sludges from three wastewater treatment plants (WWTP-A, -B, and -C) in southern Taiwan. The four compounds were analyzed from activated sludge and dewatered sludge samples, and then the samples were treated with pressure-assisted ozonation under different conditions and removal efficiencies. All four target compounds were detected, especially NP, which was detected in the highest concentrations in the activated sludges of WWTP-A and dewatered sludges of WWTP-C at 17.19 ± 4.10 and 2.41 ± 1.93 µg/g, respectively. TCS was dominant in dewatered sludges from WWTP-B, and the highest detected concentration was 13.29 ± 6.36 µg/g. Removals of 70% and 90% were attained under 150 psi at 40 cycles for NP and TCS, respectively, with 5 min of ozonation reaction time, a solid/water ratio of 1:20, and 2% ozone concentration. Ecological risk quotients (RQs) were calculated by the ratios of the 10-day Hyalella azteca (freshwater amphipod) LC50 to the environmental concentrations of the target compounds. High RQs were found to be >10 for NP, TCS, and BP-3 in untreated sludges, resulting in significant ecological risks to aquatic organisms when the sludges are arbitrarily disposed. However, the toxic effects on Hyalella azteca were not significantly different among ozone sludge treatments. The reason for this may be related to the formation of toxic oxidation by-products and incomplete mineralization of organic compounds. This could also be true for unknown intermediates. The relatively high detection frequencies of these emerging compounds in WWTP sludges requires further applications and treatments.

Elucidation of a Causal Relationship Between Platelet Count and Hypertension: A Bi-Directional Mendelian Randomization Study.

Hypertension has been reported as a major risk factor for diseases such as cardiovascular disease, and associations between platelet activation and risk for hypertension are well-established. However, the exact nature of causality between them remains unclear. In this study, a bi-directional Mendelian randomization (MR) analysis was conducted on 15,996 healthy Taiwanese individuals aged between 30 and 70 years from the Taiwan Biobank, recorded between 2008 and 2015. The inverse variance weighted (IVW) method was applied to determine the causal relationship between platelet count and hypertension with single nucleotide polymorphisms as instrumental variables (IVs). Furthermore, to check for pleiotropy and validity of the IVs, sensitivity analyses were performed using the MR-Egger, weighted median and simple median methods. This study provided evidence in support of a positive causal effect of platelet count on the risk of hypertension (odds ratio: 1.149, 95% confidence interval: 1.131-1.578, P < 0.05), using the weighted median method. A significant causal effect of platelet count on hypertension was observed using the IVW method. No pleiotropy was observed. The causal effect of hypertension on platelet count was found to be non-significant. Therefore, the findings from this study provide evidence that higher platelet count may have a significant causal effect on the elevated risk of hypertension for the general population of Taiwan.

Metal- and halide-free, solid-state polymeric water vapor sorbents for efficient water-sorption-driven cooling and atmospheric water harvesting.

Metal- and halide-free, solid-state water vapor sorbents are highly desirable for water-sorption-based applications, because most of the solid sorbents suffer from low water sorption capacity caused by their rigid porosity, while the liquid sorbents are limited by their fluidity and strong corrosivity, which is caused by the halide ions. Herein, we report a novel type of highly efficient and benign polymeric sorbent, which contains no metal or halide, and has an expandable solid state when wet. A group of sorbents are synthesized by polymerizing and crosslinking the metal-free quaternary ammonium monomers followed by an ion-exchange process to replace chloride anions with benign-anions, including acetate, oxalate, and citrate. They show significantly reduced corrosivity and improved water sorption capacity. Importantly, the water sorption capacity of the acetate paired hydrogel is among the best of the literature reported hygroscopic polymers in their pure form, even though the hydrogel is crosslinked. The hydrogel-based sorbents are further used for water-sorption-driven cooling and atmospheric water harvesting applications, which show improved coefficient of performance (COP) and high freshwater production rate, respectively. The results of this work would inspire more research interest in developing better water sorbents and potentially broaden the application horizon of water-sorption-based processes towards the water-energy nexus.

Invasive Blood Pressure Measurement and In-hospital Mortality in Critically Ill Patients With Hypertension.

Background: Invasive blood pressure (IBP) measurement is common in the intensive care unit, although its association with in-hospital mortality in critically ill patients with hypertension is poorly understood. Methods and Results: A total of 11,732 critically ill patients with hypertension from the eICU-Collaborative Research Database (eICU-CRD) were enrolled. Patients were divided into 2 groups according to whether they received IBP. The primary outcome in this study was in-hospital mortality. Propensity score matching (PSM) and inverse probability of treatment weighing (IPTW) models were used to balance the confounding covariates. Multivariable logistic regression was used to evaluate the association between IBP measurement and hospital mortality. The IBP group had a higher in-hospital mortality rate than the no IBP group in the primary cohort [238 (8.7%) vs. 581 (6.5%), p < 0.001]. In the PSM cohort, the IBP group had a lower in-hospital mortality rate than the no IBP group [187 (8.0%) vs. 241 (10.3%), p = 0.006]. IBP measurement was associated with lower in-hospital mortality in the PSM cohort (odds ratio, 0.73, 95% confidence interval, 0.59-0.92) and in the IPTW cohort (odds ratio, 0.81, 95% confidence interval, 0.67-0.99). Sensitivity analyses showed similar results in the subgroups with high body mass index and no sepsis. Conclusions: In conclusion, IBP measurement was associated with lower in-hospital mortality in critically ill patients with hypertension, highlighting the importance of IBP measurement in the intensive care unit.

Solar Seawater Distillation by Flexible and Fully Passive Multistage Membrane Distillation.

Solar-assisted distillation is considered promising to solve the freshwater supply for off-grid communities. In this work, a passive and flexible multistage membrane distillation (F-MSMD) device is devised to produce freshwater via solar distillation with the latent heat of vapor condensation being recycled to enhance its energy efficiency. By designing a siphon effect, source water is continuously wicked into the evaporation layer and the concentrated brine flows out of the device before reaching saturation, which successfully solves the otherwise challenge of salt accumulation inside the device. To achieve such siphon flow, the recycled paper is prepared from spent copy paper and used as the evaporation layer for efficient water delivery owing to its large pore size and high hydrophilicity. An eight-stage F-MSMD device exhibits a stable clean water production rate at 3.61 kg m-2 h-1 in the newly designed siphon-flow mode. This work provides a green route for designing a solar-assisted distillation device.

Estuarine sediment toxicity testing with an indigenous subtropical amphipod.

This study reports on a sediment toxicity test developed with a native amphipod strain of Ptilohyale barbicornis where sediments from 10 estuarine stations along the western coastline of Taiwan were evaluated with respect to trace metals and PAHs. The test was validated by determining dose-response relationships for aqueous copper, and cadmium and sodium dodecyl sulfate as well as copper-spiked sediment, showing a sensitivity of P. barbicornis indicating its capability serving as a toxicity test species. A significant negative correlation between growth effects after 28 days of exposure to field-collected contaminated sediments and PAHs concentrations was observed. Similarly, the chronic toxicity test showed that growth was mostly inhibited compared to controls, body lengths in particular being significantly different from controls (p < 0.05). Various estuarine sediment pollutants in the quality guidelines can be further evaluated using P. barbicornis to understand their comprehensive biological effects and ecological risks.

After remediation - Using toxicity identification evaluation of sediment contamination in the subtropical Erren river basin.

This study utilized the freshwater amphipod (Hyalella azteca) for the indication of contamination risk levels of sediment-associated contaminants in the Erren (ER1∼ER10) and Sanye Rivers (SY1∼SY5) which were contaminated by metal scrap and smelting industries for decades. Toxicity identification evaluations involving the manipulation of pore water and whole-sediment samples were conducted to identify causative pollutants. Impacts on the aquatic environment were then evaluated in order to explore how industrial development led to contaminant accumulation in sediments and resulted in biological effects. A whole-sediment TIE indicated that the major toxicant at sampling sites ER8 and SY5 was ammonia and that its toxicity was significantly reduced by the addition of zeolite. Toxicity at sampling sites ER4 and ER9 was induced by ammonia and heavy metals (Zn, Cd, Cr, As), whereas Cr was at toxic levels at ER6. ∑PAHs was another major class of contaminants at site ER2. Metals (Zn, Ni, Pb, Cd, Cr, and As) were identified as major toxic contaminants at three sites (ER3, SY1, and SY3). The application of TIEs confirmed that a causative toxicant can be identified and that its measured toxicity correlated with its concentration. In conclusion, a TIE approach was successful in demarcating most effective contaminant groups (ammonia, heavy metals, and non-polar organic compounds) in whole-sediment cores, their porewaters and potential toxicities from a highly polluted river after remediation in southern Taiwan to an invertebrate animal model H. azteca.

Structural insights into the histidine-containing phospho-transfer protein and receiver domain of sensor histidine kinase suggest a complex model in the two-component regulatory system in Pseudomonas aeruginosa.

In Pseudomonas aeruginosa, an important opportunistic pathogen that causes numerous acute and chronic infections, the hybrid two-component system (TCS) regulates the swarming ability and biofilm formation with a multistep phospho-relay, and consists of hybrid-sensor histidine kinase (HK), histidine-containing phospho-transfer protein (Hpt) and response regulator (RR). In this work, two crystal structures of HptB and the receiver domain of HK PA1611 (PA1611REC) of P. aeruginosa have been determined in order to elucidate their interactions for the transfer of the phospho-ryl group. The structure of HptB folds into an elongated four-helix bundle - helices α2, α3, α4 and α5, covered by the short N-terminal helix α1. The imidazole side chain of the conserved active-site histidine residue His57, located near the middle of helix α3, protrudes from the bundle and is exposed to solvent. The structure of PA1611REC possesses a conventional (ß/α)5 topology with five-stranded parallel ß-sheets folded in the central region, surrounded by five α-helices. The divalent Mg2+ ion is located in the negatively charged active-site cleft and interacts with Asp522, Asp565 and Arg567. The HptB-PA1611REC complex is further modeled to analyze the binding surface and interactions between the two proteins. The model shows a shape complementarity between the convex surface of PA1611REC and the kidney-shaped HptB with fewer residues and a different network involved in interactions compared with other TCS complexes, such as SLN1-R1/YPD1 from Saccharomyces cerevisiae and AHK5RD/AHP1 from Arabidopsis thaliana. These structural results provide a better understanding of the TCS in P. aeruginosa and could potentially lead to the discovery of a new treatment for infection.

FgEaf6 regulates virulence, asexual/sexual development and conidial septation in Fusarium graminearum.

Fusarium graminearum is a destructive fungal pathogen and a major cause of Fusarium head blight (FHB) which results in severe grain yield losses and quality reduction. Additionally, the pathogen produces mycotoxins during plant infection, which are harmful to the health of humans and livestock. As it is well known that lysine acetyltransferase complexes play important roles in pathogenesis, the roles of the Eaf6 homolog-containing complex have not been reported in fungal pathogen. In this study, a Eaf6 homolog FgEaf6 was identified in F. graminearum. To investigate the functions of FgEaf6, the gene was deleted using the split-marker method. ΔFgEaf6 mutant exhibited manifold defects in hyphal growth, conidial septation, asexual and sexual reproduction. Moreover, the virulence of the ΔFgEaf6 mutant was drastically reduced in both wheat heads and wheat coleoptiles. However, the FgEaf6 gene deletion did not impact DON production. An FgEaf6-gfp fusion localized to the nucleus and a conserved coiled-coil (C-C) domain was predicted in the sequence. Mutants with deletions in the C-C domain displayed similar defects during development and virulence as observed in the ΔFgEaf6 mutant. Moreover, the truncated gene was cytoplasm localized. In conclusion, the FgEaf6 encodes a nuclear protein, which plays key regulatory roles in hyphal growth, conidial septation, asexual/sexual reproduction, and the virulence of F. graminearum. The C-C is an indispensable domain in the gene. This is the first report on Eaf6 homolog functioning in virulence of fungal pathogen.

Spectrally Selective Smart Window with High Near-Infrared Light Shielding and Controllable Visible Light Transmittance.

Smart windows with high near-infrared (NIR) light shielding and controllable visible light transmittance are highly sought after for cooling energy saving in buildings. Herein, we present a rationally designed spectrally selective smart window which is capable of shielding 96.2% of the NIR irradiation from 800 to 2500 nm and at the same time permitting acceptable visible light (78.2% before and 45.3% after its optical switching) for indoor daylighting. The smart window synergistically integrates the highly selective and effective NIR absorption based photothermal conversion of cesium tungsten bronze (Cs xWO3) with the transparent thermoresponsive poly( N-isopropyl acrylamide) (PNIPAM) microgel-polyacrylamide (PAM) hydrogel. Optical switching of the smart window is a direct result of the phase transition of PAM-PNIPAM hydrogel, which in turn is induced by the photothermal effect of Cs xWO3 under sunlight irradiation. The smart window exhibits fast optical switching, shows long-term operational stability, and can be made highly flexible. Under the experimental conditions in this work, the indoor temperature with the smart window is ∼21 °C lower than that with a regular single-layered glass window under one sun irradiation. The smart window design in this work is meaningful for further development of effective smart windows for energy saving in the build environment.

Hybrid Hydrogel with High Water Vapor Harvesting Capacity for Deployable Solar-Driven Atmospheric Water Generator.

The Earth's atmosphere holds approximately 12 900 billion tons of fresh water distributed all over the world with fast replenishment. Atmospheric water harvesting is emerging as a promising strategy for clean water production in arid regions, land-locked areas, and remote communities. The water vapor sorbent is the key component for atmospheric water harvesting devices based on absorbing-releasing process. In this work, a flexible hybrid photothermal water sorbent composed of deliquescent salt and hydrogel was rationally fabricated. It possesses superior water sorption capacity even in low humidity air thanks to the deliquescent salt and maintains a solid form after it sorbs a large amount of water owing to the hydrogel platform. The harvested water could be easily released under regular sunlight via the photothermal effect, and it can be directly reused without noticeable capacity fading. An "easy-to-assemble-at-household" prototype device with 35 g of the dry hydrogel was tested outdoors under field conditions and delivered 20 g of fresh water within 2.5 h under natural sunlight. It is estimated that the material cost of making such a device to supply minimum daily water consumption for an adult (i.e., 3 kg) is only $3.20 (USD). This type of atmospheric water generator (AWG) is cheap and affordable, works perfectly with a broad range of humidity, does not need any electricity, and thus is especially suitable for clean water production in remote areas.

MFS Transporters and GABA Metabolism Are Involved in the Self-Defense Against DON in Fusarium graminearum.

Trichothecene mycotoxins, such as deoxynivalenol (DON) produced by the fungal pathogen, Fusarium graminearum, are not only important for plant infection but are also harmful to human and animal health. Trichothecene targets the ribosomal protein Rpl3 that is conserved in eukaryotes. Hence, a self-defense mechanism must exist in DON-producing fungi. It is reported that TRI (trichothecene biosynthesis) 101 and TRI12 are two genes responsible for self-defense against trichothecene toxins in Fusarium. In this study, however, we found that simultaneous disruption of TRI101 and TRI12 has no obvious influence on DON resistance upon exogenous DON treatment in F. graminearum, suggesting that other mechanisms may be involved in self-defense. By using RNA-seq, we identified 253 genes specifically induced in DON-treated cultures compared with samples from cultures treated or untreated with cycloheximide, a commonly used inhibitor of eukaryotic protein synthesis. We found that transporter genes are significantly enriched in this group of DON-induced genes. Of those genes, 15 encode major facilitator superfamily transporters likely involved in mycotoxin efflux. Significantly, we found that genes involved in the metabolism of gamma-aminobutyric acid (GABA), a known inducer of DON production in F. graminearum, are significantly enriched among the DON-induced genes. The GABA biosynthesis gene PROLINE UTILIZATION 2-2 (PUT2-2) is downregulated, while GABA degradation genes are upregulated at least twofold upon treatment with DON, resulting in decreased levels of GABA. Taken together, our results suggest that transporters influencing DON efflux are important for self-defense and that GABA mediates the balance of DON production and self-defense in F. graminearum.

Identification, contribution, and estrogenic activity of potential EDCs in a river receiving concentrated livestock effluent in Southern Taiwan.

We assessed 22 selected endocrine-disrupting compounds (EDCs) and other emerging, potentially endocrine-active compounds with estrogenic activity from the waters of the Wuluo River, southern Taiwan. This watershed receives high amounts of livestock and untreated household wastewaters. The river is surrounded by concentrated animal feedlot operations (CAFOs). River water samples were analyzed for selected compounds by liquid chromatography-tandem mass spectrometry (LC-MS/MS), T47D-KBluc reporter gene assay, and E-screen cell proliferation in vitro bioassay. Total concentrations of ∑alkylphenolic compounds (bisphenol A, 4-nonylphenol, t-nonylphenol, octylphenol, nonylphenol mono-ethoxylate, nonylphenol di-ethoxylate) were much higher than ∑estrogens (estrone, 17 ß-estradiol, estriol, 17ß-ethynylestradiol, diethylstilbestrol), ∑preservatives (methyl paraben, ethyl paraben, propyl paraben, butyl paraben), ∑UV-filters (benzophenone, methyl benzylidene camphor, benzophenone-3), ∑antimicrobials (triclocarben, triclosan, chloroxylenol), and an insect repellent (diethyltoluamide) over four seasonal sampling periods. The highest concentration was found for bisphenol A with a mean of 302 ng/L. However, its contribution to estrogenic activity was not significant due to its relatively low estrogenic potency. Lower detection rates were found for BP, EE2, TCS, and PCMX, while DES and EP were not detected. E1 and E2 levels in raw water samples were 50% higher than the predicted no-effect concentrations (PNEC) for aquatic organisms of 6 and 2 ng/L, respectively. The potency of estrogenic activity ranged from 11.7 to 190.1 ng/L E2T47D-Kbluc and 6.63 to 84.5 ng/L E2E-Screen for extracted samples. Importantly, estrone contributed 50% of the overall activity in 60% and 44% of the samples based on T47D-KBluc and MCF-7 bioassays, followed by 17 ß-estradiol, highlighting the importance of total steroid estrogen loading. This study demonstrates that the estrogenic activity of target chemicals was comparable to levels found in different countries worldwide. More intense wastewater treatment is required in areas of intensive agriculture in order to prevent adverse impacts on the ambient environment and aquatic ecosystems.

Layer-by-Layer Assembly of Fluorine-Free Polyelectrolyte-Surfactant Complexes for the Fabrication of Self-Healing Superhydrophobic Films.

Fluorine-free self-healing superhydrophobic films are of significance for practical applications because of their extended service life and cost-effective and eco-friendly preparation process. In this study, we report the fabrication of fluorine-free self-healing superhydrophobic films by layer-by-layer (LbL) assembly of poly(sodium 4-styrenesulfonate) (PSS)-1-octadecylamine (ODA) complexes (PSS-ODA) and poly(allylamine hydrochloride) (PAH)-sodium dodecyl sulfonate (SDS) (PAH-SDS) complexes. The wettability of the LbL-assembled PSS-ODA/PAH-SDS films depends on the film structure and can be tailored by changing the NaCl concentration in aqueous dispersions of PSS-ODA complexes and the number of film deposition cycles. The freshly prepared PSS-ODA/PAH-SDS film with micro- and nanoscaled hierarchical structures is hydrophilic and gradually changes to superhydrophobic in air because the polyelectrolyte-complexed ODA and SDS surfactants tend to migrate to the film surface to cover the film with hydrophobic alkyl chains to lower its surface energy. The large amount of ODA and SDS surfactants loaded in the superhydrophobic PSS-ODA/PAH-SDS films and the autonomic migration of these surfactants to the film surface endow the resultant superhydrophobic films with an excellent self-healing ability to restore the damaged superhydrophobicity. The self-healing superhydrophobic PSS-ODA/PAH-SDS films are mechanically robust and can be deposited on various flat and nonflat substrates. The LbL assembly of oppositely charged polyelectrolyte-surfactant complexes provides a new way for the fabrication of fluorine-free self-healing superhydrophobic films with satisfactory mechanical stability, enhanced reliability, and extended service life.

Highly Transparent, Nanofiller-Reinforced Scratch-Resistant Polymeric Composite Films Capable of Healing Scratches.

Integration of healability and mechanical robustness is challenging in the fabrication of highly transparent films for applications as protectors in optical and displaying devices. Here we report the fabrication of healable, highly transparent and scratch-resistant polymeric composite films that can conveniently and repeatedly heal severe damage such as cuts of several tens of micrometers wide and deep. The film fabrication process involves layer-by-layer (LbL) assembly of a poly(acrylic acid) (PAA) blend and branched poly(ethylenimine) (bPEI) blend, where each blend contains the same polyelectrolytes of low and high molecular weights, followed by annealing the resulting PAA/bPEI films with aqueous salt solution and incorporation of CaCO3 nanoparticles as nanofillers. The rearrangement of low-molecular-weight PAA and bPEI under aqueous salt annealing plays a critical role in eliminating film defects to produce optically highly transparent polyelectrolyte films. The in situ formation of tiny and well-dispersed CaCO3 nanoparticles gives the resulting composite films enhanced scratch-resistance and also retains the healing ability of the PAA/bPEI matrix films. The reversibility of noncovalent interactions among the PAA, bPEI, and CaCO3 nanoparticles and the facilitated migration of PAA and bPEI triggered by water enable healing of the structural damage and restoration of optical transparency of the PAA/bPEI films reinforced with CaCO3 nanoparticles.

Rapid and efficient multiple healing of flexible conductive films by near-infrared light irradiation.

Healable, electrically conductive films are essential for the fabrication of reliable electronic devices to reduce their replacement and maintenance costs. Here we report the fabrication of near-infrared (NIR) light-enabled healable, highly electrically conductive films by depositing silver nanowires (AgNWs) on polycaprolactone (PCL)/poly(vinyl alcohol) (PVA) composite films. The bilayer film has sheet resistance as low as 0.25 Ω·sq(-1) and shows good flexibility to repeated bending/unbending treatments. Multiple healing of electrical conductivity lose caused by cuts of several tens of micrometers wide on the bilayer film can be conveniently achieved by irradiating the film with mild NIR light. The AgNW layer functions not only as an electrical conductor but also as a NIR light-induced heater to initiate the healing of PCL/PVA film, which then imparts its healability to the conductive AgNW layer.