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Herein, we have successfully fabricated supramolecular oil gels using a combination of MXene@mGLM composites and gelator 12-hydroxystearic acid (12-HSA) in base oil polyalphaolefin (PAO) through non-covalent bonding interactions. Initially, the MXene@mGLM composites were prepared by chemically bonding carbon quantum-encapsulated liquid metal (mGLM) onto MXene nanosheets through formation of catechol–metal complexes. Subsequently, the three-dimensional (3D) network structure formed by 12-HSA through non-covalent bonding interactions was filled with a mixture of MXene@mGLM and PAO to form a supramolecular oil gel. The experimental results demonstrate that the obtained MXene@mGLM gel displays dynamic reversibility and creep resistance resulting in a significant reduction in the friction coefficient (from 0.578 to 0.103) of the PAO gel, along with a marked decrease in wear volume by 70.4%. Furthermore, beyond its lubrication properties, the MXene@mGLM gel has excellent photothermal cycle stability, enabling efficient and rapid absorption of infrared light. Additionally, the MXene@mGLM gel can undergo reversible transformation from a gel state into a liquid state by exposure to infrared light. [ABSTRACT FROM AUTHOR]

The efficiency of photodynamic therapy (PDT) is related to the subcellular localization of photosensitizers (PSs) because organelles are associated with many fundamental life-sustaining activities. In this work, we synthesized a PS (CN) based on curcumin (CUR) and obtained enhanced PDT efficiency by simultaneously targeting lipid droplets (LDs) and the endoplasmic reticulum (ER). Compared with CUR, CN with a D–π–A–π–D structure possessed stronger intramolecular charge transfer features, resulting in longer absorption and emission wavelengths. In cell imaging experiments of CN using a confocal laser scanning microscope, a bright green emission in LDs and a weak orange emission in the ER were simultaneously observed due to its sensitivity to polarity. Surprisingly, CN with low singlet oxygen yields (0.13) exhibited an excellent photodynamic effect. Further experimental results showed that the phototoxicity of CN resulted in apoptosis by destroying the ER and ferroptosis by oxidizing polyunsaturated fatty acids (PUFAs) in LDs. This work paves the way for developing more effective photosensitizers with superior dual-targeting specificity. [ABSTRACT FROM AUTHOR]

Two photosensitizers (CCOH and CCN) were designed and synthesized by introducing coumarin into the curcumin (CUR) structure. Compared with CUR, more reactive oxygen species (ROS) were generated by CCOH and CCN in type I and II synergy upon light irradiation. Cell experiments indicated that CCN with an excellent LD-targeting effect could be used to monitor the changes in the morphology and number of LDs in tumor cells during PDT. [ABSTRACT FROM AUTHOR]

The tribochemical reactions generated at the relative motion interface are considered to have a positive or negative effect on the performance when lubricating materials are in use. Obviously, these tribochemical reactions are complex and uncontrollable during sliding, resulting in an uncertainty in their performance. To enhance the lubricating properties through tribochemical reactions, herein, we designed an interfacial friction modulation system for the targeted induction of effective substance production. Noteworthily, this system achieves self-adaptive friction modulation through the targeted induction of click chemistry at the interface by copper nanoparticles and friction. In this modulation, active products are generated at the sliding interface and exert their immediate and robust lubricating improvement, avoiding exogenous synthesis and addition. By virtue of the dynamics of the tribochemical reactions, the system exhibits interesting interfacial behaviors and excellent self-adaptive properties. This system overcomes the solubility problem in various base oils and demonstrates superior performance. These important results demonstrate the possibility of regulating the friction state by the ordered design relying on tribochemical reactions. Also, the system provides a new avenue for interfacial friction modulation and the development of lubricating materials. [ABSTRACT FROM AUTHOR]

Polymer-based room temperature phosphorescence has attracted great attention for potential applications in organic light-emitting diodes, sensors, data encryption, and anti-counterfeiting. One of the most applied strategies to realize efficient room-temperature phosphorescence (RTP) is to suppress the non-radiative transition by introducing secondary interactions (hydrogen bonding, ionic bonding, etc.) between phosphors and the polymer matrix. However, water and moisture will turn off the phosphorescence emission by damaging the hydrogen bonding network. Besides, the role of the polymer matrix in the photophysical process is still unknown. Herein, we successfully achieve robust long-lived room temperature phosphorescence materials based on purely polycyclic aromatic hydrocarbons (PAHs) by in situ doping with a rigid polymer network during polymerization. The materials exhibited an ultralong phosphorescence lifetime of up to 1.27 s, a large Stokes shift of 233 nm and a remarkable duration of afterglow for over 12 s, which are extremely stable even under aqueous conditions. Photophysical analysis and transient absorption spectroscopy reveal that phosphorescence is facilitated by accelerating the intersystem crossing (ISC) from singlet to triplet states and suppressing the non-radiative transition of the triplet excitons within the rigid polymer matrix. Furthermore, 3D phosphorescent structures and 2D large-scale, transparent displays with re-writable encoded information are fabricated with the facilely processed PAHs@polymer RTP materials. [ABSTRACT FROM AUTHOR]

Bioinspired nanochannel systems exhibiting analogous energy conversion characteristics have attracted great interest. Here, we develop a nanochannel array by modifying bilayer light-responsive molecules onto specific segments of alumina nanochannels. Based on the energy level difference between positively charged poly(3-thiophene-phenyl-tridecyl ammonium bromide) (PT2) and negatively charged cis-bis-(4,4-dicarboxy-2,2-bipyridine)dithiocyanato ruthenium(II) (N3), a bulk heterojunction is established that induces the transfer of excited electrons from donor PT2 to acceptor N3 following a "Z-scheme", which is conducive to improving ion selective transport and total transmembrane ion flux. The nanochannel array shows excellent cation selectivity and diode-like ion rectification behavior. Incorporating the enhancement of surface charge density, a record light-induced ion current change (PICC) ratio of 128% is achieved in the PT2/N3(T) nanochannel array. Owing to the synergistic effect of salinity gradient energy and light irradiation, the ion current induced by the bulk heterojunction significantly increases the output power density. The maximum improvement of power density is 79% at a load resistance of 0.7 kΩ. This work provides a new route to develop high-performance photoelectric conversion systems and integrated osmotic power generation. [ABSTRACT FROM AUTHOR]

Here, a magnetic responsive composite surface (MRCS) was prepared by injecting a magnetic elastomer into ZnO nanoarrays for intelligent control of droplet/bubble transport. This non-pollution, non-contact operation method has shown great potential in micro-fluids, micro-chemical reactors, chip laboratory environments and other related applications. [ABSTRACT FROM AUTHOR]

Here, we adopted a simple method to prepare an integrated mesh with an anisotropic surface (IMAS). The motion mode of the droplet can be switched by changing the tilt angle of the IMAS. This low-cost and convenient operation method has great application potential in biomimetic functional surface preparation, microfluidics, etc. [ABSTRACT FROM AUTHOR]

Transition metal nitrides have good metallic conductivity and high pseudocapacitance, which have drawn extensive attention in the research of Zn-ion energy storage systems. In this paper, we present a novel fabrication of carbon cloth-supported TiN-coated carbon nanotube composites (TiN/CNTs@CC and TWC) via a CVD–ALD method using ethanol, TiCl4 and H2O as precursors. The prepared TWC composites can be used as self-supported electrodes with good flexibility and conductivity. Electrochemical performance tests show that the TiN/CNTs@CC electrode has a high specific capacitance of 363.5 F g−1 at 0.5 A g−1, good rate capability and excellent cycling stability with 92.9% capacity retention over 10 000 charge/discharge cycles. Impressively, the assembled zinc ion hybrid capacitor can achieve a high energy density of up to 81.8 W h kg−1 at a power density of 137.7 W kg−1. Even at a power density of 3013.7 W kg−1, a high energy density of 26.4 W h kg−1 is still achieved. This study provides a new insight into the application of nitride-derived carbon materials in zinc-ion hybrid capacitors. [ABSTRACT FROM AUTHOR]

The non-invasive treatment of glioblastoma (GBM) is of great significance and can greatly reduce the complications of craniotomy. Sonodynamic therapy (SDT) is an emerging tumor therapeutic strategy that overcomes some fatal flaws of photodynamic therapy (PDT). Different from PDT, SDT has deep tissue penetration and can be applied in the non-invasive treatment of deep-seated tumors. However, effective sonosensitizers that can be used for SDT of GBM are still very rare. Herein, we have prepared a suitable assembly based on a hypocrellin derivative (CTHB) with good biocompatibility. Excitedly, the hypocrellin-based assembly (CTHB NPs) can effectively produce reactive oxygen species under ultrasound stimulation. The inherent fluorescence and photoacoustic imaging characteristics of the CTHB NPs are conducive to the precise positioning of the tumors. It has been proved both in subcutaneous and in intracranial tumor models that CTHB NPs can be used as an effective sonosensitizer to inhibit tumor growth under ultrasound irradiation. This hypocrellin-based assembly has a good clinical prospect in the non-invasive treatment of GBM. [ABSTRACT FROM AUTHOR]

Cellulose is a kind of low-cost, widely-sourced and environmentally friendly material. In this paper, a cellulose acetate/cellulose fiber paper composite membrane was prepared through a phase inversion process. Combining the advantages of these two materials, the composite membrane has good antifouling performance and excellent wear resistance. [ABSTRACT FROM AUTHOR]

A bromine-substituted thermally activated delayed fluorescent (TADF) molecule AQCzBr2 is designed with both small singlet–triplet splitting (ΔEST) and increased spin–orbit coupling (SOC) to boost intersystem crossing (ISC) for singlet oxygen generation. AQCzBr2 nanoparticles (NPs) demonstrate high productivity of singlet oxygen generation (ΦΔ = 0.91) which allows highly efficient photodynamic therapy toward cancer cells. [ABSTRACT FROM AUTHOR]

Functional superamphiphobic coatings have attracted much attention due to their promising application prospects in oil transportation and anti-contamination, which call for the requirements of flame retardancy. Herein, a novel superamphiphobic F–HAP–SiO2 hybrid coating with excellent flame retardant properties was fabricated by in situ growing SiO2 particles on hydroxyapatite. For the prepared superamphiphobic hydroxyapatite (Ca10(OH)2(PO4)6) coating, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, energy dispersive spectroscopy (EDS), thermogravimetric analysis and three-dimensional topography were performed. The superamphiphobic hydroxyapatite (Ca10(OH)2(PO4)6) coating features high contact angles and low sliding angles for various liquids, including n-decane with low surface tension (23.3 mN m−1). Different liquid droplets can retain a perfectly quasispherical shape on the coating surface. Most interestingly, liquid marbles wrapped up by this superamphiphobic powder can "stand" on various substrates without any collapse. Moreover, it is noted that the intrinsic fire-resistant nature of the coating enables its application onto various substrates and reduces the risk of fire due to the excellent oleophobic and oil resistant properties of the coating, exhibiting its great substrate independence. In addition, the coating shows a good repellency for liquids (HCl, NaOH, milk, honey, and coffee) after the mechanical damage tests. In summary, the fluorinated hydroxyapatite (Ca10(OH)2(PO4)6) coatings with superior superamphiphobicity, flame-retardancy, substrate independence nature and mechanical stability show promising potential in water/oil/fire-proof, self-cleaning, and antifouling coating applications. [ABSTRACT FROM AUTHOR]

Notoriously, a superhydrophobic surface always shows underwater superoleophilic behaviour in aqueous environments. However, a question remains unanswered: is superhydrophobicity equal to underwater superoleophilicity? Gaps of understanding still exist between such two extreme wetting states. Herein, beyond the thermodynamic contradiction, a well-defined porous coating integrating a simultaneous in-air superhydrophobic and underwater superoleophobic state can be realized via the rational incorporation of hydrophilic microscale defects on a superhydrophobic matrix. In contrast, a predictable underwater superoleophilic state is observed on the pristine superhydrophobic surface with completely hydrophobic surface chemistry. We underline how the hydrophilic defects regulate the underwater oil wetting and in-air water repellence simultaneously, and the superhydrophobic surface is not simply equal to the underwater superoleophilic surface. On the basis of understanding the underlying mechanism, the separation of light oil–water mixtures and surfactant-stabilized oil-in-water emulsions can be achieved using the defective superhydrophobic surface. Such findings could shed light on understanding repellence/penetration behaviours at a three phase contact line and accelerating the realization of opposite wetting states without any external stimulus. [ABSTRACT FROM AUTHOR]

A mixed edible wax coating on elastic substrates comprising sphere-shaped carnauba wax and flake-shaped beeswax superhydrophobic particles with a two-stage application (before/after stretching) shows durability against abrasion, scratch healing, self-cleaning performance, and sealing ability after stretching. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) have emerged as potential lubricants in 2001. Subsequently, there has been tremendous research interest in ILs from the tribology society since their discovery as novel synthetic lubricating materials. This also expands the research area of ILs. Consistent with the requirement of searching for alternative and eco-friendly lubricants, IL lubrication will experience further development in the coming years. Herein, we review the research progress of IL lubricants. Generally, the tribological properties of IL lubricants as lubricating oils, additives and thin films are reviewed in detail and their lubrication mechanisms discussed. Considering their actual applications, the flexible design of ILs allows the synthesis of task-specific and tribologically interesting ILs to overcome the drawbacks of the application of ILs, such as high cost, poor compatibility with traditional oils, thermal oxidization and corrosion. Nowadays, increasing research is focused on halogen-free ILs, green ILs, synthesis-free ILs and functional ILs. In addition to their macroscopic properties, the nanoscopic performance of ILs on a small scale and in small gaps is also important in revealing their tribological mechanisms. It has been shown that when sliding surfaces are compressed, in comparison with a less polar molecular lubricant, ion pairs resist "squeeze out" due to the strong interaction between the ions of ILs and oppositely charged surfaces, resulting in a film that remains in place at higher shear forces. Thus, the lubricity of ILs can be externally controlled in situ by applying electric potentials. In summary, ILs demonstrate sufficient design versatility as a type of model lubricant for meeting the requirements of mechanical engineering. Accordingly, their perspectives and future development are discussed in this review. [ABSTRACT FROM AUTHOR]

A GGT-activated two-photon fluorescent probe (4F-2CN–GSH) was developed based on a cascade reaction. 4F-2CN–GSH could selectivily detect GGT with low detection limit and distinguish ovarian cancer cells from normal cells using both one-photon and two-photon fluorescence imaging. [ABSTRACT FROM AUTHOR]

Mussel-inspired chemistry, owing to its unique and versatile functions to manipulate dynamic molecular-scale interactions, has emerged as a powerful tool for the rational design and synthesis of new hydrogels. In particular, possessing a myriad of unique advantages that are otherwise impossible by conventional counterparts, mussel-inspired hydrogels have been widely explored in numerous fields such as biomedical engineering, soft electronics and actuators, and wearable sensors. Despite great excitement and vigor, a comprehensive and timely review on this emerging topic is missing. In this review, we discuss (1) the fundamental interaction mechanisms underpinning the spectacular wet adhesion in natural mussels and mussel-inspired materials; (2) the key routes to engineering hydrogels by leveraging on the interactions of mussel-inspired building blocks; (3) the emerging applications of mussel-inspired hydrogels, especially in the areas of flexible electronics and biomedical engineering; (4) the future perspectives and unsolved challenges of this multidisciplinary field. We envision that this review will provide an insightful perspective to stimulate new thinking and innovation in the development of next-generation hydrogels and beyond. [ABSTRACT FROM AUTHOR]

Mechanically weak superwetting materials are difficult to apply to real complex environments for efficient crude oil-in-water emulsion separation. Herein, robust TiO2-coated meshes were fabricated by spraying titanium dioxide nanoparticles (TiO2 P25) and aluminum phosphate (AP) binder suspension on a stainless steel mesh. The AP with inorganic adhesive was developed to enhance the bonding force between nanoparticle coatings and the stainless steel meshes and the detailed interaction mechanism has been comprehensively explained. The robust TiO2-coated meshes show excellent underwater superoleophobicity, even for crude oil. Moreover, the underwater superoleophobic meshes enjoy eminent separation capacity for various oil-in-water emulsions, including crude oil-in-water emulsion, with separation efficiency higher than 99.8% even after 10 cycles. Furthermore, the coated meshes can maintain separation efficiencies of over 99.4% after 500 scratch cycles, sand impact cycles, solvent immersion tests and ultrasonic treatment. The mechanical durability of the mesh causes it to have great prospects in extensive industrial applications and harsh circumstances. In addition, the mesh can be successfully used for degrading organic dyes with high efficiency under UV light irradiation, making it a prospective candidate for wastewater treatment. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) have been the focus of much research due to their excellent lubricity and anti-wear properties. However, when they are used as lubricating oil additives, they tend to agglomerate and precipitate, because of which achieving good dispersion stability is a significant problem. This manuscript reports a new strategy to successfully resolve the problem of poor dispersion stability of CNTs in the lubricating material 12-hydroxystearic acid (12-HSA) supramolecular gel. On the one hand, the carbon nanotubes are trapped in the network of the supramolecular gel which greatly reduces its reaggregation in the 500SN base oil. On the other hand, the carbon nanotubes significantly improved the thermal, mechanical and tribological properties of the supramolecular gel. For example, the decomposition temperature is increased by 30 °C as the 500SN base oil molecules are trapped in the 3-D network of supramolecules. The viscoelasticity of the supramolecular gel is improved when the carbon nanotubes are used as additives. The results also show that a small quantity of modified carbon nanotubes as additives can significantly reduce friction and wear. And the CNTs and acidified carbon nanotubes (CNTHs) can provide the same friction coefficient as both of them are trapped in the 3-D network of the quasi-solid state 12-HSA soft-nanocomposite. In addition, we performed experiments and molecular dynamics simulations to explore the microstructure and self-assembly mechanism of the soft-nanocomposite lubricant. The soft-nanocomposite lubricant not only prolonged the useful life of machinery, but also reduced the waste of resources, which is significant in sustainable development. [ABSTRACT FROM AUTHOR]

Superantiwetting surfaces with contact angles above 150° and sliding angles below 10° for one wetting phase under another medium phase among water, oil, and air have been designed. However, all superantiwetting surfaces that show super-repellence in any two-phase system including six extreme wetting states such as superhydrophobicity, superoleophobicity, underoil superhydrophobicity, underwater superoleophobicity, and underoil and underwater superaerophobicity are extremely rare. Here, we prepare all superantiwetting surfaces by simply spraying a suspension containing titanium dioxide, aluminum phosphate, and perfluorosilane on substrates. In a broad sense, the all superantiwetting state can be extended to polar liquid–nonpolar liquid–air systems. Thus, the prepared surfaces realize high-efficiency on-demand separation of immiscible organic liquids. This discovery opens up the possibility of multiple extreme wetting surfaces even involving a wide range of organic liquids. [ABSTRACT FROM AUTHOR]

Lotus leaf-inspired superhydrophobic, fish scale-inspired underwater superoleophobic, and the switchable superwetting surfaces have been broadly developed by entire modification with water-repellent, water-loving, and smart components, respectively. Inspired by beetles, here a strategy of fractional modification is proposed to construct dual superlyophobic surfaces that have both superhydrophobic and underwater superoleophobic properties. Specifically, copper-based coatings on various substrates are fractionally modified by adjusting the concentration of perfluorinated mercaptan. The obtained dual superlyophobic surfaces display mutual advantages like using either superhydrophobic or underwater superoleophobic materials without any continuous external stimulus, for example on-demand oil–water separation. In theory, the distinctive dual superlyophobic state exists in a narrow range of surface chemistry, and thus needs elaborate surface modification. This discovery will facilitate the extension of the surfaces with completely opposite superwettability to enjoy the superiority in interfacial issues and applications. [ABSTRACT FROM AUTHOR]

Understanding the complementary roles of surface roughness and energy in natural super-non-wetting surfaces has greatly promoted the development of biomimetic superhydrophobic surfaces that repel water at a much greater rate than oils. These surfaces that are highly repellent to low-surface-tension oils and organic liquids, termed superoleophobic surfaces, are poorly understood. Inspired by springtails (collembolan), a third factor, re-entrant surface curvature, has been introduced to the design and fabrication system of superoleophobic surfaces in conjunction with two other factors of surface chemical composition and roughness. Over the past decade, superoleophobic surfaces have attracted tremendous attention with respect to their design, fabrication and applications due to their extraordinary properties. This review focuses on these aspects and thus summarizes recent research progress in superoleophobic surfaces. Starting from the origin, features of natural oil-resistant creatures have been introduced, and fundamental theories for surface design have been discussed. Calculations suggest that creation of these surfaces requires specific re-entrant structures and fluoride modifiers. Based on this principle, various fabrication methods, from top-down to bottom-up approaches, have been used, and some derivative structures with desirable properties have been produced. A precise and detailed classification has been provided in this review that includes representative methods and structures as well as functions (i.e., transparence and self-healing). Significantly, superoleophobic materials have many valuable applications, including oil pollution resistance, oil transportation, and synthesis of mesoporous supraparticles. However, their complicated manufacturing techniques, poor physical–chemical properties and environmentally unfriendly surface chemicals jointly impede their real-life applications. Therefore, it is highly necessary to optimize the craft and performance of theses surfaces for industrial operation and practical applications. To this end, some challenges and perspectives will be provided regarding the future research and development of superoleophobic surfaces. [ABSTRACT FROM AUTHOR]

Synthesis of photothermal agents with absorption in the near-infrared (NIR) region and featuring excellent photostability, high photothermal conversion efficiency, and good biocompatibility is necessary for the application of photothermal therapy (PTT). In this work, a low band gap thiophene–benzene–diketopyrrolopyrrole (TBD)-based polymer was synthesized and used to fabricate TBD polymer nanoparticles (TBDPNPs) through a one-step nanoprecipitation method. The obtained near-infrared-absorbing TBDPNPs presented good water dispersibility, high photothermal stability, and low toxicity. Significantly, the TBDPNPs exhibited an ultrahigh photothermal conversion efficiency of approximately 68.1% under 671 nm laser irradiation. In addition, photoacoustic (PA) imaging, with high spatial resolution and deep tissue penetration, showed that the TBDPNPs targeted tumor sites through the enhanced permeability and retention effect. Therefore, the robust TBDPNPs with a photothermal conversion efficiency of 68.1% can serve as an excellent therapeutic agent for PA-imaging-guided PTT. [ABSTRACT FROM AUTHOR]

Sand, an abundant natural resource, is the cause behind the harsh environmental conditions of the desert, such as water shortages and sand storms. Because of the strong hydrophilicity of sand itself, water can be quickly absorbed by sand, which greatly impedes desert greening, water storage and transportation projects. In contrast to this conventional understanding of sand (i.e., superhydrophilicity), we propose the design of “superhydrophobic sand”, aimed to address issues associated with the desert environment and sand resource utilization. In our experiments, three kinds of hydrophobic sands with different surface structures and wettability properties were successfully prepared by cladding nonmetal (SiO2) and metal (Ag and Cu) inorganic materials on sand grain surfaces and then modifying them with low-surface-energy chemicals. Combining superhydrophobicity with desert sand, superhydrophobic sand (PFDS-sand@SiO2) is shown to have excellent water repellency, allowing water to stably remain and flow on such a sand surface without any wetting or permeation. Furthermore, the superhydrophobic sand demonstrates a great water-holding capacity, such that a sand layer with a thickness of 2 cm can sustain a water column height of 35 cm. Very significantly, PFDS-sand@SiO2 exhibits extremely high thermal stability up to 400 °C when used for water storage. This result is unprecedented and sufficient for facing the high-temperature conditions of the desert environment and some others. In addition to reliable water storage, such superhydrophobic sand also demonstrates a great anti-flow-dragging effect during water transportation, whereby a water droplet can smoothly and quickly roll down a simulated sand channel (13 cm length) within 0.3 s (∼0.45 m s−1). All of these manifestations imply the significant potential of such “superhydrophobic sand” in its application to desert water storage and transportation. [ABSTRACT FROM AUTHOR]

Fluorescent protein biosensors are popular reporters for biological processes and life sciences, but their fundamental working mechanisms remain unclear. To characterize the functional fluorescence events on their native timescales, we implemented wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS) to shed light on a blue-green emission-ratiometric fluorescent protein based Ca2+ biosensor with a single Pro377Arg mutation. The transient Raman modes of the embedded chromophore from ca. 1000–1650 cm−1 exhibit characteristic intensity and frequency dynamics which infer the underlying atomic motions and photochemical reaction stages. Our experimental study reveals the hidden structural inhomogeneity of the protein local environment upon Ca2+ binding with the mutated arginine residue trapping multiple chromophore subpopulations, which manifest distinct time constants of ∼16 and 90 ps for excited state proton transfer (ESPT) following 400 nm photoexcitation. The altered ESPT reaction pathways and emission properties of the Ca2+ biosensor represent the foundational step of rationally designing advanced fluorescent protein biosensors to tune their functionalities by site-specifically altering the local environment (e.g., the active site) of the embedded chromophore. [ABSTRACT FROM AUTHOR]

As a smart and new energy harvesting device, triboelectric nanogenerators (TENGs) are able to convert almost all mechanical energies into electricity. However, the complex preparation process requires coating with a conductive layer, which limits their practical applications. Herein, a new type of triboelectric nanogenerator is fabricated using gum wrappers coated with aluminium foil as the conduction layer. To further enhance the output of the paper-based TENG, polydopamine molecules are introduced to improve the surface polarity of the friction layer by a simple self-polymerization reaction at room temperature. After chemical modification, the short-circuit current and output voltage are enhanced by more than 3.5 times with maximum values of 30 μA and 1000 V, respectively. The charge density increases from 21 μC m−2 to 76 μC m−2, which can light up 496 commercial LEDs. Based on the above TENGs, a self-powered cathodic protection anticorrosion system is designed to protect A3 steel from corrosion in 3.5% NaCl solution. Furthermore, the TENG powered cathodic protection system also has good antifouling properties, which can prevent algae from attaching onto metallic substrates. This work demonstrates a recyclable, cost-effective paper-based TENG, which has great potential for practical use in marine anticorrosion and antifouling. [ABSTRACT FROM AUTHOR]

Proton transfer reactions are functionally important in numerous chemical and biological processes. To unravel proton scavengers in action with atomistic details, we studied excited-state proton transfer (ESPT) from photoacid pyranine to the weak base acetate in methanol using transient absorption and wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS). Proton transfer is inhibited in neat methanol, but coherent proton motions and the formation of a charge-separated state occur on the sub-picosecond (sub-ps) timescale, accompanied by chromophore solvation wherein the longitudinal relaxation time of methanol (∼9 ps) dominates. With acetate ions added, bimolecular diffusion-controlled ESPT from the photoacid to acetate occurs on the ∼30 ps timescale, followed by ∼600 ps diffusion-assisted charge separation and solvation in the methanol H-bonding network. Besides intensity dynamics, frequency redshift and blueshift of the transient ∼285 and 1525 cm−1 modes track ESPT after 400 nm photoexcitation. Tunable FSRS exploits resonance Raman enhancement with optimal wavelengths, extends the detection window of excited-state vibrational modes to low frequency, and enables a deeper mechanistic understanding of the proton transfer reaction to proton scavengers in an organic solvent. [ABSTRACT FROM AUTHOR]