Donor-Acceptor Modulating of Ionic AIE Photosensitizers for Enhanced ROS Generation and NIR-II Emission.

Photosensitizers (PSs) with aggregation-induced emission (AIE) characteristics are competitive candidates for bioimaging and therapeutic applications. However, their short emission wavelength and nonspecific organelle targeting hinder their therapeutic effectiveness. Herein, a donor-acceptor modulation approach is reported to construct a series of ionic AIE photosensitizers with enhanced photodynamic therapy (PDT) outcomes and fluorescent emission in the second near-infrared (NIR-II) window. By employing dithieno[3,2-b:2',3'-d]pyrrole (DTP) and indolium (In) as the strong donor and acceptor, respectively, the compound DTP-In exhibits a substantial redshift in absorption and fluorescent emission reach to NIR-II region. The reduced energy gap between singlet and triplet states in DTP-In also increases the reactive oxygen species (ROS) generation rate. Further, DTP-In can self-assemble in aqueous solutions, forming positively charged nanoaggregates, which are superior to conventional encapsulated nanoparticles in cellular uptake and mitochondrial targeting. Consequently, DTP-In aggregates show efficient photodynamic ablation of 4T1 cancer cells and outstanding tumor theranostic in vivo under 660 nm laser irradiation. This work highlights the potential of molecular engineering of donor-acceptor AIE PSs with multiple functionalities, thereby facilitating the development of more effective strategies for cancer therapy.

In-situ sparse-array imaging for through-thickness cracks in plates with A0 Lamb waves and an efficient waveform inversion algorithm.

Structural health monitoring (SHM) requires efficient online crack detection and characterization to prevent structural failures, which mainly arise from fatigue cracks. Existing solutions for crack characterization involve analyzing sensed wave signals directly, but these approaches usually require onerous steps or many sensors to obtain sufficient and clear wave packets. An alternative strategy is a model-based inversion, which takes the full waveform into consideration and does not require analysis on a single wave packet. This approach can achieve accurate characterization with fewer sensors and simpler implementation. We propose an efficient model based on the Huygens' principle and the no-mode-conversion property of the A0 mode Lamb waves to meet the requirements of online monitoring. We then verify the proposed model-based crack imaging method through simulation and experiments on smooth and rough cracks. The proposed method is easy, cheap, and efficient, making it a desirable option for SHM tasks.

Highly Efficient Aligned Ion-Conducting Network and Interface Chemistries for Depolarized All-Solid-State Lithium Metal Batteries.

Improving the long-term cycling stability and energy density of all-solid-state lithium (Li)-metal batteries (ASSLMBs) at room temperature is a severe challenge because of the notorious solid-solid interfacial contact loss and sluggish ion transport. Solid electrolytes are generally studied as two-dimensional (2D) structures with planar interfaces, showing limited interfacial contact and further resulting in unstable Li/electrolyte and cathode/electrolyte interfaces. Herein, three-dimensional (3D) architecturally designed composite solid electrolytes are developed with independently controlled structural factors using 3D printing processing and post-curing treatment. Multiple-type electrolyte films with vertical-aligned micro-pillar (p-3DSE) and spiral (s-3DSE) structures are rationally designed and developed, which can be employed for both Li metal anode and cathode in terms of accelerating the Li+ transport within electrodes and reinforcing the interfacial adhesion. The printed p-3DSE delivers robust long-term cycle life of up to 2600 cycles and a high critical current density of 1.92 mA cm-2. The optimized electrolyte structure could lead to ASSLMBs with a superior full-cell areal capacity of 2.75 mAh cm-2 (LFP) and 3.92 mAh cm-2 (NCM811). This unique design provides enhancements for both anode and cathode electrodes, thereby alleviating interfacial degradation induced by dendrite growth and contact loss. The approach in this study opens a new design strategy for advanced composite solid polymer electrolytes in ASSLMBs operating under high rates/capacities and room temperature.

Switchable NaCl cages via a MWCNTs/Ni[Fe(CN)6]2 nanocomposite for high performance desalination.

With the application of nanomaterials in seawater desalination technology increasing, the adjustable characteristics of carbon-based nanomaterials make it possible to use multiwalled carbon nanotube (MWCNT) materials in seawater desalination technology. In this study, Ni[Fe(CN)6]2 is loaded onto the inner wall of MWCNTs by the co-precipitation method to prepare MWCNTs with variable pore size, making it a switchable cage for NaCl. During the procedure, most of the Ni[Fe(CN)6]2 is transferred to the outer surface of the MWCNTs after adsorption, and NaCl is stored inside the MWCNTs (which have been proved by characterization); at the same time, Ni can improve the cell stability of Ni[Fe(CN)6]2. The effect of adsorbent reaction time and addition amount on the desalination performance of MWCNTs/Ni[Fe(CN)6]2 has been tested. According to the results, the best desalination performance of MWCNTs/Ni[Fe(CN)6]2 is 1354.6 mg g-1 when the reaction time is 0.5 h and the addition amount is 20 mg. After 3 cycles of adsorption and desorption, its desalting performance decreased to 242.3 mg g-1.

A geopolymer membrane for application in a structural mechanics and energy storage difunctional supercapacitor.

A structural mechanics and energy storage difunctional supercapacitor based on a geopolymer membrane injected with a 0.5 M Na2SO4 electrolyte and a pseudocapacitive electrode Mn7O13 is designed and assembled. The geopolymer membrane is prepared as a structural electrolyte with metakaolin and alkaline activator solution. The wide channels in the geopolymer matrix provide paths for ion movement. The Mn7O13 electrode is prepared by different hydrothermal treatments at different temperatures and times, and assembled with activated carbon and a geopolymer with different moduli to form a difunctional supercapacitor. The results show that the electrode sample annealed at 300 °C for 45 min after hydrothermal treatment at 160 °C for 24 h exhibits the best comprehensive performance. The specific capacitance of the electrode is 175.5 F g-1 (2392.6 F m-2) at 1 A g-1, and the specific capacitance of the difunctional structure supercapacitor assembled with a geopolymer with a modulus of 1.2 and cured for 28 days is 144.12 F g-1 (1960.0F m-2) at 1 A g-1 under 15 MPa.

A Highly Transparent Photo-Electro-Thermal Film with Broadband Selectivity for All-Day Anti-/De-Icing.

A photo- and electro-thermal film can convert sunlight and electricity into heat to solve icing problems. Combination of them provides an efficient strategy for all-day anti-/de-icing. However, only opaque surfaces have been reported, due to the mutual exclusiveness between photon absorption and transmission. Herein, a highly transparent and scalable solution-processed photo-electro-thermal film is reported, which exhibits an ultra-broadband selective spectrum to separate the visible light from sunlight and a countertrend suppress of emission in longer wavelength. It absorbs ≈ 85% of invisible sunlight (ultraviolet and near-infrared) for light-heat conversion, meanwhile maintains luminous transmittance > 70%. The reflection of mid-infrared leads to low emissivity (0.41), which further preserves heat on the surface for anti-/de-icing purpose. This ultra-broadband selectivity enables temperature elevation > 40 °C under 1-sun illumination and the mutual support between photo-thermal and electro-thermal effects contributes to > 50% saving of electrical consumption under weak solar exposure (0.4-sun) for maintaining unfrozen surfaces at -35 °C environment. The reverberation from photo-electro-thermal and super-hydrophobic effects illustrates a lubricating removal of grown ice in short time (< 120 s). The self-cleaning ability and the durability under mechanical, electrical, optical, and thermal stresses render the film stable for long-term usage in all-day anti-/de-icing applications.

Low-dimensional high entropy oxide (FeCoCrMnNi)3O4 for supercapacitor applications.

Previous studies have found that high entropy oxides can be used as electrode materials for supercapacitors. However, there is still the problem of their low energy density. We tried to increase the energy density while increasing the specific capacitance of high entropy oxides from the potential window. Transition metal elements Fe, Co, Cr, Mn and Ni were selected for their electrochemical activity, and high entropy oxides were prepared by a sol-gel method under different calcination temperatures. The calcination temperature affects the structural morphology and crystallinity of the high entropy oxides and thus also affects the electrochemical performance. The spinel-phase (FeCoCrMnNi)3O4 with a high specific surface area of 63.1 m2 g-1 was prepared at a low calcination temperature of 450 °C. The specific capacitance is 332.2 F g-1 at a current density of 0.3 A g-1 in 1 M KOH electrolyte with a wide potential window of (-1, 0.6). An improved energy density of 103.8 W h kg-1 is reached via the designed microstructure of the high entropy oxide electrode.

Direct Amination of α-Triaryl Alcohols via Vanadium Catalysis.

α-Triaryl amines have been used as pharmaceuticals and pharmaceutical intermediates for antifungal and anticancer applications. Current methods to synthesize such compounds require at least two steps, and no direct amination of tertiary alcohols has been reported. Herein, we disclose efficient catalytic conditions for the direct amination of α-triaryl alcohols to access α-triaryl amines. VO(OiPr)3, a commercially available reagent, has been identified as an effective catalyst for the direct amination of several α-triaryl alcohols. This process is scalable, as demonstrated by a gram-scale synthesis, and the reaction still works at as low as a 0.01 mol % catalyst loading with the turnover number reaching 3900. Moreover, commercial pharmaceuticals including clotrimazole and flutrimazole have been successfully prepared rapidly and efficiently using this newly developed method.

Mechanochromic Optical/Electrical Skin for Ultrasensitive Dual-Signal Sensing.

Following earlier research efforts dedicated to the realization of multifunctional sensing, recent developments of artificial skins endeavor to go beyond human sensory functions by integrating interactive visualization of strain and pressure stimuli. Inspired by the microcracked structure of spider slit organs and the mechanochromic mechanism of chameleons, this work aims to design a flexible optical/electrical skin (OE-skin) capable of responding to complex stimuli with interactive feedback of human-readable structural colors. The OE-skin consists of an ionic electrode combined with an elastomer dielectric layer, a chromotropic layer containing photonic crystals and a conductive carbon nanotube/MXene layer. The electrode/dielectric layers function as a capacitive pressure sensor. The mechanochromic photonic crystals of ferroferric oxide-carbon magnetic arrays embedded in the gelatin/polyacrylamide stretchable hydrogel film perceive strain and pressure stimuli with bright color switching outputs in the full visible spectrum. The underlying microcracked conductive layer is devoted to ultrasensitive strain sensing with a gauge factor of 191.8. The multilayered OE-skin delivers an ultrafast, accurate response for capacitive pressure sensing with a detection limit of 75 Pa and long-term stability of 5000 cycles, while visualizing complex deformations in the form of high-resolution spatial colors. These findings offer deep insights into the rational design of OE-skins as multifunctional sensing devices.

Quantitative evaluation of dissociated optic nerve fibre layer (DONFL) following idiopathic macular hole surgery.

OBJECTIVES: To quantitatively evaluate concentric macular dark spots (CMDS) on spectral-domain optical coherence tomography (SD-OCT) to determine the morphological characteristics of dissociated optic nerve fibre layer (DONFL) following the performance of internal limiting membrane (ILM) peeling in patients with full-thickness idiopathic macular hole (IMH) closure. METHODS: Retrospective study on patients who underwent a vitrectomy with ILM peeling procedure. BCVA, cross-sectional OCT scans, and three-dimensional reconstructions of en face OCT scans were analysed preoperatively, at 2, 6, 12 months post-operatively. A novel image analysis technique was used to automatically measure DONFL logical properties through the radius, area, the nerve fibre layer dissociation index (NFLDI), and depth of the CMDS. RESULTS: 53 eyes of 51 patients were included, and the mean follow-up was 11.53 ± 6.26 months. CMDS was found in 46 (86.79%) eyes within 2 months after ILM peeling and 50 (94.34%) eyes within 6 months after ILM peeling. CMDS concentrated on the temporal side of the macula in all 50 eyes (100%) at first detection. The area, NFLDI, and depth of CMDS in four quadrants developed significantly during the postoperative 6 months (p < 0.05), and then these changes slowed down and remained unchanged 12 months post-operatively. The morphological changes in the temporal quadrant were significantly greater than those in other quadrants at 2, 6, 12 months (all p < 0.05) post-operatively. CONCLUSIONS: CMDS mostly appeared and concentrated on the temporal side of the macula in IMHs within two months after ILM peeling and progressed within 6 months and remained unchanged after 12 months.

Flow Electrode Capacitive Deionization System with Simultaneous Desalting of Na+ and Gathering of Na.

Oceans contain many freshwater resources and metal elements that people need, so the rational development of marine resources can solve the two major problems of shortage of freshwater resources and metal elements for people. To solve these two challenges, a system was designed to obtain freshwater resources and metallic elements simultaneously. An ion enrichment module was added to the conventional flow capacitor deionization system to collect metal elements while the seawater was deionized. A flowing electrode allows the metal elements to enter the flowing electrode through the desalination ability. It transports the metal elements to the enrichment module through the fluidity of the fluid while reducing the ion concentration at the flowing electrode, thus reducing the effect caused by the rejection of the same ion and collecting and enriching the metal elements. We purchased activated carbon to test the feasibility of the system with different mass fractions of activated carbon suspensions. The results showed that the elemental enrichment capacity of the system increased from 12.291 to 14.795 mg, and the enrichment rate increased from 13.536 to 16.294 mg cm-2 h-1 as the mass fraction of activated carbon increased. Thus, the system accomplished the goals of desalination and metal collection simultaneously.

Scalable anisotropic cooling aerogels by additive freeze-casting.

Cooling in buildings is vital to human well-being but inevitability consumes significant energy, adding pressure on achieving carbon neutrality. Thermally superinsulating aerogels are promising to isolate the heat for more energy-efficient cooling. However, most aerogels tend to absorb the sunlight for unwanted solar heat gain, and it is challenging to scale up the aerogel fabrication while maintaining consistent properties. Herein, we develop a thermally insulating, solar-reflective anisotropic cooling aerogel panel containing in-plane aligned pores with engineered pore walls using boron nitride nanosheets by an additive freeze-casting technique. The additive freeze-casting offers highly controllable and cumulative freezing dynamics for fabricating decimeter-scale aerogel panels with consistent in-plane pore alignments. The unique anisotropic thermo-optical properties of the nanosheets combined with in-plane pore channels enable the anisotropic cooling aerogel to deliver an ultralow out-of-plane thermal conductivity of 16.9 mW m-1 K-1 and a high solar reflectance of 97%. The excellent dual functionalities allow the anisotropic cooling aerogel to minimize both parasitic and solar heat gains when used as cooling panels under direct sunlight, achieving an up to 7 °C lower interior temperature than commercial silica aerogels. This work offers a new paradigm for the bottom-up fabrication of scalable anisotropic aerogels towards practical energy-efficient cooling applications.

INTERNAL LIMITING MEMBRANE PEELING DISTORTS THE RETINAL LAYERS AND INDUCES SCOTOMA FORMATION IN THE PERIFOVEAL TEMPORAL MACULA.

PURPOSE: To determine whether internal limiting membrane peeling damages retinal function in patients with an idiopathic macular hole. METHODS: Retrospective case series. Forty-five eyes of 45 idiopathic macular hole patients who underwent vitrectomy with internal limiting membrane peeling with a minimum follow-up of 6 months. Each patient received a complete ophthalmological examination. The eyes were examined by microperimetry MP-3 in the central 20° visual field and optical coherence tomography angiography in the central 6 × 6 mm area. RESULTS: Six months after the surgery, macular hole closed in each patient. Retinal sensitivity decreased significantly in the perifoveal temporal ETDRS sector (from 24.97 ± 2.67-19.98 ± 5.68 dB, P = 0.001) but not in the other sectors. Six patients (13%) developed 24 scotomas, 62.5% presented in the perifoveal temporal sector. Anatomically, bumps in the outer nuclear layer were discovered concurrent with inner retinal dimples on B-scan images, predominantly (76.8%) in the perifoveal temporal sector, which have not been previously reported. The incidence of outer nuclear layer bumps was significantly higher in patients with scotomas than in those without (83% vs. 18%, P = 0.014). CONCLUSION: Internal limiting membrane peeling induced functional changes specifically in the perifoveal temporal macula. Distortion in the retinal layers is proposed to underly scotomas pathogenesis.

Study on the Application Value of Concurrent Chemoradiotherapy and Clinical Nursing Pathway for Postoperative Patients with Esophageal Cancer.

Backgrounds: To observe the value of concurrent chemoradiotherapy and clinical nursing pathway for postoperative patients with esophageal cancer (EC). Methods: A total of 88 postoperative EC patients were divided into the radiotherapy group (RG group, 44 cases) and the chemoradiotherapy group (CRG group, 44 cases). The RG group received single three-dimensional conformal radiotherapy+clinical nursing pathway, and the CRG group was combined with chemotherapy on this basis. The 5-year overall survival rate, progression-free survival rate, pathological remission and survival rate, lymph node metastasis and survival rate, quality of life analysis, tumor-related factor level, and incidence of adverse reactions were compared between the two groups. Results: The overall survival rates at 1, 3, and 5 years were 93.18%, 56.82%, and 50.0% in the CRG group and 86.36%, 52.27%, and 43.18% in the RG group, respectively. The 5-year progression-free survival rate of the CRG group was 60.87%, which was clearly higher than that of the RG group (33.33%). The 1-, 3-, and 5-year overall survival rates of pCR and NpCR patients were 90.48%, 80.95%, and 61.90% and 89.55%, 44.78%, and 38.81%, respectively. The overall 1-year, 3-year, and 5-year survival rates were 81.08%, 37.84, and 24.32% and 96.08%, 66.67%, and 62.75% in patients with lymph node metastasis and nonlymph node metastasis, respectively, with statistical significant differences. The emotional function, physical function, cough, pain, and eating difficulty in the CRG group were better than those in the RG group. After treatment, serum CEA, SCC, CYFRA21-1, and CA199 levels in the CRG group were obviously downregulated compared with those in the RG group. There was no obvious difference in the incidence of adverse reactions between the CRG group and the RG group. Conclusion: Single radiotherapy and concurrent chemoradiotherapy can be used as effective means in the treatment of EC. Moreover, the quality of life and survival time of the concurrent chemoradiotherapy group were dramatically better than those of the single radiotherapy group, and the antitumor ability of the concurrent chemoradiotherapy group was stronger.

Accelerating the Layup Sequences Design of Composite Laminates via Theory-Guided Machine Learning Models.

Experimental and numerical investigations are presented for a theory-guided machine learning (ML) model that combines the Hashin failure theory (HFT) and the classical lamination theory (CLT) to optimize and accelerate the design of composite laminates. A finite element simulation with the incorporation of the HFT and CLT were used to generate the training dataset. Instead of directly mapping the relationship between the ply angles of the laminate and its strength and stiffness, a multi-layer interconnected neural network (NN) system was built following the logical sequence of composite theories. With the forward prediction by the NN system and the inverse optimization by genetic algorithm (GA), a benchmark case of designing a composite tube subjected to the combined loads of bending and torsion was studied. The ML models successfully provided the optimal layup sequences and the required fiber modulus according to the preset design targets. Additionally, it shows that the machine learning models, with the guidance of composite theories, realize a faster optimization process and requires less training data than models with direct simple NNs. Such results imply the importance of domain knowledge in helping improve the ML applications in engineering problems.

Catalytic pyrolysis of film waste over Co/Ni pillared montmorillonites towards H2 production.

The transformation of plastic waste into valuable fuel products via catalytic pyrolysis is a promising and eco-friendly strategy. Herein, a series of Co/Ni pillared montmorillonites were developed as low-cost and effective catalysts for the pyrolysis of post-consumer film waste, which is one of the representative plastic wastes in nature. The best-performing catalyst produced 80.2% of liquid product, with a high selectivity of 43.5% of hydrocarbons at C10-C13 range, and 42.0 vol% of H2 which is nearly increased by 40-fold as compared to that in non-catalytic run. The improved results were ascribed to the pillared structure, the oxidation state of Co/Ni, and the distribution of acid sites. Particularly, the Lewis acidity (which governs the cyclization and alkanisation) coupled with high surface area and uniform dispersion of transition metallic sites, were found to promote the selectivity of condensable product. The pyrolytic mechanism towards H2 production was explored by theoretical calculations. The lattice oxygen bonded to both Ni and Co in an octahedral environment was found to promote the adsorption of the fragment of polymer in dehydrogenation. Additionally, the solid residues are potentially applied for the production of valuable carbonaceous materials since they displayed high heating value. This work is expected to provide a direction for the development of pyrolysis technology for fuel production with sustainability and economic viability.

Sirt1 Mediates Vitamin D Deficiency-Driven Gluconeogenesis in the Liver via mTorc2/Akt Signaling.

As an active form of vitamin D (VD), 1,25-dihydroxyvitamin D (1,25(OH)2D3) is involved in the development of many metabolic diseases, such as diabetes, autoimmune diseases, and tumours. While prospective epidemiological studies have consistently implicated VD deficiency in the regulation of glucose metabolism and insulin sensitivity, the specific mechanism remains unclear. Here, we generated 1α(OH)ase-null mice (targeted ablation of the 25-hydroxyvitamin D 1α hydroxylase enzyme) and found that these mice developed hepatic glucose overproduction, glucose intolerance, and hepatic insulin resistance accompanied by reduced Sirtuin 1 (Sirt1) expression. The chromatin immunoprecipitation (ChIP) and a luciferase reporter assay revealed that 1,25(OH)2D3-activated VD receptor (VDR) directly interacted with one VD response element (VDRE) in the Sirt1 promoter to upregulate Sirt1 transcription, triggering a cascade of serine/threonine kinase (AKT) phosphorylation at S473 and FOXO1 phosphorylation at S256. This phosphorylation cascade reduced the expression of gluconeogenic genes, eventually attenuating glucose overproduction in the liver. In addition, a signaling pathway was found to modulate gluconeogenesis involving VDR, Sirt1, Rictor (a component of mTOR complex 2 [mTorc2]), AKT, and FOXO1, and Sirt1 and FOXO1 were identified as key modulators of dysregulated gluconeogenesis due to VD deficiency.

Retinal Dopamine D2 Receptors Participate in the Development of Myopia in Mice.

Purpose: To learn more about the locations of dopamine D2 receptors (D2Rs) that regulate form-deprivation myopia (FDM), using different transgenic mouse models. Methods: One eye of D2R-knockout (KO) mice and wild-type littermates was subjected to four weeks of monocular FDM, whereas the fellow eye served as control. Mice in both groups received daily intraperitoneal injections of either the D2R antagonist sulpiride (8 µg/g) or vehicle alone. FDM was also induced in retina- (Six3creD2Rfl/fl) or fibroblast-specific (S100a4creD2Rfl/fl) D2R-KO mice. A subset of retina-specific D2R-KO mice and D2Rfl/fl littermates were also given sulpiride or vehicle injections. Refraction was measured with an eccentric infrared photorefractor, and other biometric parameters were measured by optical coherence tomography (n ≈ 20 for each group). Results: FDM development was attenuated in wild-type littermates treated with sulpiride. However, this inhibitory effect disappeared in the D2R-KO mice, suggesting that antagonizing D2Rs suppressed myopia development. Similarly, the development of myopia was partially inhibited by retina-specific (deletion efficiency: 94.7%) but not fibroblast-specific (66.9%) D2R-KO. The sulpiride-mediated inhibitory effects on FDM also disappeared with retinal D2R-KO, suggesting that antagonizing D2Rs outside the retina may not attenuate myopia. Changes in axial length were less marked than changes in refraction, but in general the two were correlated. Conclusions: This study demonstrates that D2Rs located in the retina participate in dopaminergic regulation of FDM in mice. These findings provide an important and fundamental basis for further exploring the retinal mechanism(s) involved in dopamine signaling and myopia development.

Autonomous Visualization of Damage in Polymers by Metal-Free Polymerizations of Microencapsulated Activated Alkynes.

The development of autonomous materials with desired performance and built-in visualizable sensing units is of great academic and industrial significance. Although a wide range of damage indication methods have been reported, the "turn-on" sensing mechanism by damaging events based on microcapsule systems, especially those relying on chemical reactions to elicit a chromogenic response, are still very limited. Herein, a facile and metal-free polymerization route with an interesting reaction-induced coloration effect is demonstrated. Under the catalysis of 1,4-diazabicyclo[2.2.2]octane (DABCO), the polymerizations of difunctional or trifunctional activated alkynes proceed very quickly at 0 °C in air. A series of polymers composed of stereoregular enyne structure (major unit) and divinyl ether structure (minor unit) are obtained. Both the catalyst and monomers are colorless while the polymerized products are deep-colored. This process can be applied for the damage visualization of polymers using the microencapsulation technique. Microcapsules containing the reactive alkyne monomer are prepared and mixed in a DABCO-dispersed polymer film. Both the external and internal damage regions of this composite film can be readily visualized once the reaction is initiated from the ruptured microcapsules. Moreover, the newly formed polymer automatically seals the cracks with an additional protection function.

Interdigitated Three-Dimensional Heterogeneous Nanocomposites for High-Performance Mechanochromic Smart Membranes.

Mechanochromic smart membranes capable of optical modulation have great potential in smart windows, artificial skins, and camouflage. However, the realization of high-contrast optical modulation based on light scattering activated at a low strain remains challenging. Here, we present a strategy for designing mechanochromic scattering membranes by introducing a Young's modulus mismatch between the two interdigitated polydimethylsiloxane phases with weak interfaces in a periodic three-dimensional (3D) structure. The refractive index-matched interfaces of the nanocomposite provide a high optical transparency of 93%. Experimental and computational studies reveal that the 3D heterogeneity facilitates the generation of numerous nanoscale debonds or "nanogaps" at the modulus-mismatching interfaces, enabling incident light scattering under tension. The heterogeneous scatterer delivers both a high transmittance contrast of >50% achieved at 15% strain and a maximum contrast of 82%. When used as a smart window, the membrane demonstrates effective diffusion of transmitting sunlight, leading to moderate indoor illumination by eliminating extremely bright or dark spots. At the other extreme, such a 3D heterogeneous design with strongly bonded interfaces can enhance the coloration sensitivity of mechanophore-dyed nanocomposites. This work presents insights into the design principles of advanced mechanochromic smart membranes.