Flexible Bilayer Research Articles

High-Performance Organic Field-Effect Transistors and Inverters with Good Flexibility and Low Operating Voltage.

Organic field-effect transistors (OFETs) with good flexibility and low operating voltage, are of great meaning for the low power stretchable and wearable electronic devices. The operating voltage and flexibility are easily affected by the dielectric layers in the OFETs. Bilayer dielectrics comprising both high- and low-permittivity (k) insulating polymers, have been reported. The flexible bilayer dielectrics can combine the advantages of both insulating polymers, which are high charge carriers from low-k polymers and low operating voltage from high-k polymers. However, the effect of film thicknesses in the bilayer dielectrics on the OFET performance is seldom investigated. Here, bilayer dielectrics comprising high-k polyvinyl alcohol (PVA) and low-k polymethylmethacrylate (PMMA) were fabricated. And PVA/PMMA bilayers with three different PVA film thicknesses are carefully investigated. The 300 nm PVA/100 nm PMMA bilayer dielectric makes the pentacene OFETs show the highest hole mobility of 1.24 cm2V-1s-1 and the corresponding inverters give a high voltage gain of 40 and a noise margin of 2.3 V (77% of 1/2 VDD) at low operating voltage of 6 V. Both the pentacene transistors and the inverters still work properly under bending radium of 5.85 mm, proving the good prospects of the PVA/PMMA bilayer dielectric in practical applications.

Abstract 4436: Phenotypic heterogeneity in pancreatic ductal adenocarcinoma revealed by single-cell lipidomics

Abstract Introduction: The high chemoresistance of pancreatic ductal adenocarcinoma (PDAC) is partly attributed to the phenotypic plasticity and high adaptability of PDAC cells to the challenges of the harsh microenviroment. Phenotypic presentation of the PDAC cell is also determined by the lipid composition of the plasma membrane and lipid species that organize the rigid or more flexible lipid bilayer and determine the cellular mobility and plasticity. Lipids are also important energy and signaling molecules that contribute to the aggressiveness of the cell. Here we focus on differences in lipid profile of PDAC cells in epithelial and mesenchymal cell state using single-cell lipidomics approach (SpaceM). Methods: Lipid profile of 2D cultures of eight conventional and ten primary patient derived cell lines of different source (patient derived xenograft, ascites, primary tumor, organoid derived) was investigated. Epithelial (E) or mesenchymal (M) cell state was evaluated by gene and protein expression of EMT markers. Matrix-Assisted Laser Desorption/Ionization (MALDI)-imaging MS was used for data acquisition on positive ion mode at 25 µm step size and m/z range of 600-1000. For annotating lipids in MALDI-imaging data, we used the METASPACE cloud software. For constructing single-cell lipidomic profiles we used the SpaceM method. In total, around 150.000 cells were analyzed and 1400 lipid ions detected. Results: Gene expression analysis suggested prominent metabolism of structural lipids in the conventional epithelial cells. In UMAP analysis of single cell lipidomics data, each cell line, conventional and primary, presented a unique lipid fingerprint with however prominent clustering into the two phenotypes, epithelial and mesenchymal. We detected enrichment of alkyl-acyl phosphatidylcholines, alkyl-acyl phospatidylethanolamines, ceramides and sphingolipids in the epithelial phenotype. Mesenchymal phenotype was enriched for lipids involved in lateral diffusion and low bilayer thickness supporting the increased fluidity of the mesenchymal cell membrane. Furthermore, mesenchymal phenotype was enriched for lipid droplets and energy storing triacylglycerols, also confirmed by histological lipid droplet staining. Conclusions: Using the single cell lipid information, a successful grouping to epithelial or mesenchymal subtype could be performed regardless of sample source, suggesting a conserved lipid profile typical for the two states. Further detailed investigation of single cell lipidomics data aims to unveil the prominent epithelial-mesenchymal state lipid markers and open a niche for functional investigations of cell-state specific markers and potential cell-state targeting. Citation Format: Marija Trajkovic-Arsic, Jeany Delafiori, Mohammed Shahraz, Corinna Münch, Smiths S. Lueong, Sven T. Liffers, Doris Hellerschmied, Theodore Alexandrov, Jens T. Siveke. Phenotypic heterogeneity in pancreatic ductal adenocarcinoma revealed by single-cell lipidomics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4436.

Insight into the liposomal encapsulation of mono and bis-naphthalimides.

Mitonafide-loaded liposomes are a promising strategy to overcome the neurotoxicity observed in clinical trials for this drug. This study investigates the influence of loaded mitonafide or a dimer analogue on different liposomal formulations and their therapeutic efficacy in vitro. Physicochemical properties of the liposomes were manipulated using different loading methods (namely bilayer or core loading) and varying the rigidity of the bilayer using distinct phospholipid compositions. Our results demonstrated that the mitonafide dimer analogue had a comparable encapsulation efficiency (EE%) into the liposomes when loaded into rigid or flexible bilayers in contrast to the low mitonafide monomer EE%. A pH gradient core loading method resulted in a more efficient mechanism to load the monomer into the liposomes. DOSY NMR and spectrofluorometric studies revealed key differences in the structure of the vesicles and the arrangement of the monomer or the dimer in the bilayer or the core of the liposomes. The in vitro assessment of the formulations using MDA-MB-231 and RT-112 cells revealed that a flexible lipid bilayer allows a faster drug release, which correlated well with the spectroscopy studies. This study investigated for the first time that the characteristics of the lipid bilayer and the loading method influence the encapsulation efficacy, colloidal properties, photoactivity and stability of mono and bis-naphthalimides loaded in a liposomal carrier, essential factors that will impact the performance of the formulation in a biological scenario.

Efficient Strategy for Radiative Cooling Based on Ultra-Broad-Band Infrared Regulation of Flexible Bilayer Film.

Flexible thermal radiation films with adjustable broad-band infrared radiation could maintain various heat-generating electronic devices working stably in corresponding operating temperatures, making them good candidates for radiative cooling (RC) material. However, the controllable radiation peaks of the metamaterial were narrow, and manipulation was a time-consuming and complex process. Herein, we design a simple TiN/Si bilayer film with controllable broad-band radiation peaks at a thermal radiation wavelength of 3.5-20 μm by impedance matching. Meanwhile, the different bilayer films applied to aluminum devices at different temperatures exhibit outstanding heat dissipation efficiency and maintain the corresponding equilibrium temperature to ensure that devices work stably for a long time. Moreover, the bilayer films deposited on the flexible PI substrates exhibit preferable thermostability and higher tensile strength than existing radiative cooling materials deposited on PDMS, PE, PMMA or TPX, etc. This work provides an effective strategy to realize efficient radiation cooling for flexible electronic devices and spacecraft appendages.

Photo‐activated shape memory polymer with chiral twisting based on anisotropic bilayer thin sheets

AbstractThe remotely controlled shape memory behaviors of a two‐dimensional (2D) sheet to controlled helix structure upon external stimuli is of great significance in the field of smart materials. Herein, we devise a strategy to fabricate a series of shape memory polycaprolactone/W18O49 nanowire film via highly efficient UV‐triggered thiol‐acrylate click chemistry. The resultant polymer composites exhibited desirable photothermal transfer efficiency and can enable rapid temperature increase over the melting temperature of polymeric matrix, thus remotely actuating shape transformation within 8 s. Owing to the well‐defined architecture of the polymer network, the fabricated elastic composite film exhibited a high degree of crystallinity and showed excellent shape memory properties with Rf of 93.12% and Rr of 95.32%. Remarkably, under a 160 mW/cm2 simulated sunlight illumination, the transformation of flat 2D film into 3D chiral actuators is driven by designing anisotropic bilayer thin sheet, and it yields right‐ and left‐handed helix. This work will pave the way for designing biomimetic flexible actuators toward multifunctional shape‐shifting devices.Highlights Shape memory polycaprolactone/W18O49 nanowires composite film is fabricated via UV‐triggered thiol‐ene click chemistry. Polymer composites exhibit light‐activated shape memory behaviors. The composite films show excellent shape fixity and shape recovery ratio based on the well‐defined network. The shape morphing behaviors of a flexible 2D bilayer strip into 3D chiral actuators are achieved.

Fabry-Perot cavity tunable multicolor flexible electrochromic device based on porous filter membrane

In recent years, Fabry-Perot (F-P) cavity-type electrochromic devices composed of more stable inorganic materials have been extensively investigated for achieving colorful reflective displays and military camouflage functions. However, the majority of reported substrates for colorful F-P cavity electrochromic devices are rigid conductive glasses, which hinders their practical application in flexible reflective displays and camouflage. Herein, we construct a WO3/W/Au bilayer F-P cavity multicolor tunable electrochromic device based on a flexible porous filter membrane, in which WO3, an inorganic electrochromic material, is used as the electrochromic layer, metallic W as the partial reflective layer, and metallic Au as the total reflective and conductive layer. Highly flexible bilayer F-P cavity multicolor electrochromic devices have been prepared by combining UV-curable electrolytes and thermoplastic sealing procedures. By adjusting the thickness of the WO3 layer, a wide spectrum of colors including yellow, purplish red, violet, blue, green, olivine, peach, etc. can be obtained. In addition, by adjusting the driving voltage of the electrochromic device, more precise color adjustment can be achieved. The electrochromic device has a fast coloring (2.06 s) and bleaching (2.70 s) response time, providing a new solution for future flexible colorful reflective display devices.

PHARMACOKINETIC STUDY IN HUMANS AND IN VITRO EVALUATION OF BIOENHANCED BILAYER SUBLINGUAL FILMS FOR THE MANAGEMENT OF ACUTE MIGRAINE

Objective: Long-lasting migraine pain is one of the most disabling neurological disorders and requires a quick onset of action from the administered dosage form. This study aimed to provide sublingual administration of the frequently used combination of NSAID and triptan in order to trigger their action immediately by escaping the first-pass metabolism, simultaneously improving patient compliance. Methods: In the present research, sublingual bilayer films were developed by joining the two loaded layers with zolmitriptan and piroxicam, respectively. Each layer was prepared and loaded separately using the traditional solvent casting method. Mechanical support was provided by the 1:1 combination of HPMC E-15 and pullulan, which were used as water-soluble film-forming polymers with polyethylene glycol 400 as a plasticizer. Films were evaluated for various physicochemical and mechanical properties. Finally, a pharmacokinetic study was performed on six healthy human volunteers to compare the PK parameters of the best formulation, BSTF-3, with those of a commercially available formulation. Sepitrap 80 and Sepitrap 4000 were used as bio-enhancers to achieve faster systemic delivery. Results: The thin, flexible bilayer films were observed to provide quick action alone with increase patient compliance by preventing the first-pass metabolism and dysphagia. Sepitrap 80 successfully increased the permeation of both drugs. Approximately 92 percent of zolmitriptan was released from the formed bilayer sublingual thin films within 3 min, whereas 92 percent of piroxicam was released within 4.5 min from the best formulation. Within 30 min of the commencement of the pharmacokinetic investigation, plasma concentrations of the active component began to rise rapidly. Conclusion: When compared to commercial formulations, the developed films had a greater AUC and Cmax with a shorter Tmax, indicating a faster trigger of action and higher bioavailability.

Interface-mediated ferroelectricity in PMN-PT/PZT flexible bilayer via pulsed laser deposition

Ferroelectric thin-film bilayers of Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT)/PbZr0.52Ti0.48O3 (PZT) were grown on a flexible substrate of mica using pulsed laser deposition. Growth of the bilayer was induced with a thin film of LaNiO3 (LNO) single crystal, which was deposited on a mica substrate through van der Waals epitaxy. The LNO thin film also serves as the electrode for the bilayer device. The growth of the LNO thin film along the ⟨ 100 ⟩ orientation adopts a “Stranski–Krastanov” mechanism, governed by the relaxation of elastic energy between LNO/mica. Compared with the single layers of PMN-PT or PZT, or the bilayer of PZT/PMN-PT, the PMN-PT/PZT bilayer exhibits enhanced ferroelectric properties, with remnant polarization up to 72 μC/cm2. In addition, polarization in the PMN-PT/PZT bilayer exhibits excellent resistance against mechanical bending fatigue over 108 switching cycles. Such improved performances are ascribed to spontaneous polarizations enhanced by the residual stress at the PMN-PT/PZT heterointerface, increased interfacial potential barrier against leakage, and suppressed diffusion of Nb or Mg across the interface.

A flexible bilayer p-NiO/n-ZnO films with photodetecting properties in self power mode

We report highly efficient flexible p-NiO/n-ZnO heterojunction UV photodetectors. NiO and ZnO thin films were grown on plastic polyethylene terephthalate (PET) substrates by dc magnetron sputtering for constructing high quality interfaces. The diode has shown an excellent rectification ratio i.e. 106 under dark mode and observed more than 80% transparency in the visible region. Investigated structural, compositional, and optical properties of the film to correlate the UV photodetector transport characteristics. Further, UV illumination devices exhibit an excellent responsivity of 0.24 A W−1 with a detectivity of 1.25 × 1011 jones and the highest external quantum efficiency of 83.14% achieved at −5 V of bias. The device shows the fastest speed of response with rise/fall times of 86.10 ms/106.60 ms, accomplished at −1 V with the lowest optical power density. The photodiode has shown incredible characteristics that are mainly attributed to the built-in potential and the transport mechanism at the interface.

Customizing multiple superlyophobic surfaces in water-oil-air systems: From controllable preparation to smart switching via manipulating heterogeneous surface chemistry

Superlyophobicity that is being subdivided to multiple extreme wetting states has unique superiority in a specific interfacial application. Controllable preparation and smart switching of multiple superlyophobic surfaces are significant but remain a challenge. Here a flexible bilayer strategy is presented to construct three kinds of multiple superlyophobic surfaces with controllable extreme wetting behaviors of water and oil droplets in air while ultimately showing underoil superhydrophobicity and underwater superoleophobicity. A robust hydrophobic polyacrylate adhesive can be used expediently to adjust the heterogeneous surface chemistry resulting from extremely-low-surface-energy CF chain and water-loving TiO2 sol. Moreover, solvent-triggered process and ultraviolet irradiation enable smart switching among these fine superwetting states. Under the stimuli, the heterogeneous surface chemistry is further regulated by reconstruction of the bilayer components. Utilizing the superhydrophobic and underwater superoleophobic properties, the smart membrane realizes effective on-demand emulsion separation. This study provides an approach to customize smart surfaces with switchable superwettability among subdivided multiple superlyophobicity.

Addressing the Superior Drug Delivery Performance of Bilosomes─A Microscopy and Fluorescence Study.

The global health scenario in present times has raised human awareness about drug delivery strategies. Among colloidal drug delivery vehicles, vesicular nanocarriers such as liposomes and niosomes are popular. However, liposomes and niosomes get disrupted in the harsh environment of the gastrointestinal tract. In this context, the drug delivery community has reported the superior performance of vesicles containing bile salts, that is, bilosomes. The present work attempts to examine the structural/morphological aspects underlying the superior performance of bilosomes. Optical microscopy, electron microscopy, and light scattering give a definite proof of the enhanced stability of bilosomes compared to niosomes, both prepared from the same amphiphilic molecule. Fluorescence probing of the vesicles provides detailed insight into the bilayer characteristics and the differences between bilosomes and niosomes. Fluorescence resonance energy transfer studies lend further support to the findings that bilosomes have a more flexible bilayer structure than niosomes. The entrapment efficiency of the vesicles for the well-known antioxidant curcumin (whose bioavailability is a matter of concern due to low water solubility) was also studied. Bilosomes show higher curcumin entrapment efficiency than niosomes. For use in drug delivery, one needs to establish a trade-off between cargo/drug entrapment and release. Thus, a flexible bilayer structure is an advantage.

A polyzwitterion-based antifouling and flexible bilayer hydrogel coating

A coating of implanted medical devices with antifouling ability, preferable mechanical property and stability in the physiological environment proves beneficial for their clinical use. Here we develop a flexible bilayer hydrogel coating with self-healing, antifouling, and lubricating functions. Our bilayer coating consists of two functional layers: i) an adhesive flexible polyelectrolyte hydrogel layer, ii) an antifouling and lubricous polyzwitterionic layer. The bilayer hydrogel coating is prepared in two steps dip-coating and in situ UV photopolymerization. Our results demonstrate that the prepared bilayer hydrogel coating has proper mechanical properties, favorable hydrophilicity, and lower surface friction. We demonstrate that the bilayer hydrogel coating maintains hydrophilicity under extreme condition (1 h sonicating or 5000 times repeating bending). The as-prepared bilayer hydrogel coating resists non-specific protein adsorption, inhibits cell and platelet adhesion, and prevents thrombosis. This work provides a reliable coating on the medical materials, showing a promising practical application in diversified implantable medical devices.

4D-printed bilayer hydrogel with adjustable bending degree for enteroatmospheric fistula closure.

Recently, four-dimensional (4D) shape-morphing structures, which can dynamically change shape over time, have attracted much attention in biomedical manufacturing. The 4D printing has the capacity to fabricate dynamic construction conforming to the natural bending of biological tissues, superior to other manufacturing techniques. In this study, we presented a multi-responsive, flexible, and biocompatible 4D-printed bilayer hydrogel based on acrylamide-acrylic acid/cellulose nanocrystal (AAm-AAc/CNC) network. The first layer was first stretched and then formed reversible coordination with Fe3+ to maintain this pre-stretched length; it was later combined with a second layer. The deformation process was actuated by the reduction of Fe3+ to Fe2+ in the first layer which restored it to its initial length. The deformation condition was to immerse the 4D construct in sodium lactate (LA-Na) and then expose it to ultraviolet (UV) light until maximal deformation was realized. The bending degree of this 4D construct can be programmed by modifying the pre-stretched lengths of the first layer. We explored various deformation steps in simple and complex constructs to verify that the 4D bilayer hydrogel can mimic the curved morphology of the intestines. The bilayer hydrogel can also curve in deionized water due to anisotropic volume change yet the response time and maximum bending degree was inferior to deformation in LA-Na and UV light. Finally, we made a 4D-printed bilayer hydrogel stent to test its closure effect for enteroatmospheric fistulas (EAFs) in vitro and in vivo. The results illustrate that the hydrogel plays a role in the temporary closure of EAFs. This study offers an effective method to produce curved structures and expands the potential applications of 4D printing in biomedical fields.

Flexible bilayer terahertz metasurface for the manipulation of orbital angular momentum states.

Metasurfaces employed for generating orbital angular momentum (OAM) beams have drawn tremendous interest since they can offer extensive applications ranging from quantum optics to information processing over the subwavelength scale. In this study, a flexible bilayer metasurface is proposed and experimentally verified in the terahertz (THz) region. Based on Pancharatnam-Berry (P-B) phase, the proposed meta-atom satisfies perfect polarization-flipping at the design frequency and is implemented for the generation of vortex beams under circularly polarized (CP) illumination. Two metasurfaces are designed, fabricated and experimentally characterized with a THz spectral imaging system for linearly polarized (LP) illumination. The transmitted field intensity distribution of y component is petal-shaped of gradually varied pieces with the frequency due to the complementary symmetric structure, indicating OAM state transition between a single vortex beam and superposition of two vortex beams. The measured spectral imaging distributions of amplitude and phase show good agreement with the simulation results. Such designs open a pathway for modulation of THz OAM states and bring more possibilities for flexible metasurfaces in a THz application.

Physicochemical and superficial characterization of a bilayer film of zein and pectin obtained by electrospraying

AbstractThe preparation by electrospraying of a bilayer film formed by a pectin layer (hydrophilic, polar) and a zein layer (hydrophobic, nonpolar), is a difficult task that has not yet been reported. Herein, the feasibility of producing films by electrostatic atomization was studied, as well as the changes in the superficial and physicochemical characteristics of the bilayer film. Results showed that it is possible to produce a flexible and yellow bilayer film (101.07 ± 8.11 μm) with a continuous surface structure and a well‐defined interface, without chemical interactions between both layers nor antimicrobial activity. This study is one of the first to show that the electrospraying technique can be used to generate biodegradable bilayer films using hydrophilic/hydrophobic biopolymer solutions.

A Flexible Bilayer Actuator Based on Liquid Crystal Network and PVDF–TrFE for Low‐Grade Waste Heat Harvesting

Flexible low‐grade waste heat generators are a promising device that can both recycle thermal energy and exhibit elasticity, are light weight, and have easily customized shapes. However, most thermal energy recovery technologies only work at large temperature gradients. Herein, a dynamic generator based on liquid crystal network (LCN) and poly(vinylidenedifluoride–trifluoroethylene) (PVDF–TrFE) is reported. The generator can operate in a temperature of ≈30 °C with a temperature difference of 6 K. LCN expands and shrinks in the temperature fluctuation, which is beneficial for PVDF–TrFE exposure to greater temperature changes. The device is found to exhibit a maximum output voltage of ≈4.5 mV based on pyroelectric and piezoelectric effect. This simple strategy may broaden applications of liquid crystalline actuators for harvesting low‐grade waste heat.

A Comparative Formulation Development and Evaluation of Tazarotene Ethosomal and Transfersomal Gel for Effective Management of Acne

Acne vulgaris is the most prevalent disorder in the period before puberty when increased adrenal androgen level causes enlargement of the sebaceous glands and it increased the production of sebum on the face, chest, and back. This disease is caused due to interaction between many causative agents or pathogenic components which lead to formation of the acne and those are seborrhea, follicular hyper keratinization, microbial formation of pilosebaceous unit by Propionibacterium acne and arrival of inflammatory mediators. Tazarotene is a well-known retinoid related to vitamin A that belongs to an acetylenic class of retinoid, used in the management of acne. Oral administration of Tazarotene causes changes in bone morphology after prolonged exposure to high doses, which also exhibit teratogenicity but this does not occur with topical delivery. Ethosomes are non-invasive delivery carriers enabling drugs to reach to the bottom of the skin layers and/or the system and transfersomes are the self-adaptable ultra-deformable flexible elastic bilayer vesicles composed of phospholipids able to penetrate through the pores of skin even smaller than its size. Present research aims the comparative evaluation of ethosomal and transfersomal gels loaded with Tazarotene in the treatment of acne. In the present study, ethosomes and transfersomes were formulated by the cold method and hand-shaking method, respectively, followed by loading of Tazarotene and development into gel formulation. The formulated gel samples were evaluated for in vitro release study, in vitro permeation study, in vitro anti-acne study, in vivo percutaneous permeation study by CLSM, and in vivo anti-acne study. The results proved that both the formulated ethosomal and transfersomal gels have better permeation through the skin but ethosomal gel showed better release in comparison to transfersomal gel, also final gels exhibited the anti-acne potentiality.

Magnetically propelled soft micromachines with multipatterned fabrications

The rotation of the helical micromachines can produce efficient motion efficiency at small-scale conditions and have the potential for multi-field applications. In this study, we propose self-scrolling schemes aiming at a flexible bilayer structure that includes the strained layer and magnetic layer. The magnetic layer is composed of magnetic nanocomposites and can respond to an external magnetic field. To cope with multistructural configurations, multipatterned manufacturing solutions of machines were investigated. Under the actuation of the rotating magnetic field, the swimming abilities of the helical machines are investigated in water and in a more viscous medium, exhibiting excellent movement abilities. For the purpose of transport capacities, the machines could be patterned with the containers, and their magnetic properties were studied to evaluate the effect of containers of different lengths on the movement performance; here, the direction of the magnetic axis and the stability of the rotational motion were investigated under different magnetization conditions. The result demonstrated that the larger radial deviation of the magnetic axis allows the machines to swim wobbly, and these instabilities can be reduced by radial magnetization.

Laser-induced photothermal generation of flexible and salt-resistant monolithic bilayer membranes for efficient solar desalination

Harvesting solar energy and generating steam through solar thermal energy are viable approaches with diverse applications such as power generation, desalination, and water purification. Particularly, for efficient and stable solar desalination, hierarchically porous materials are desired to enable the required multiple functionalities. However, high thermal/chemical energy required and time consumed remain roadblocks. In this study, a facile, fast, and scalable laser-induced photothermal method to achieve flexible monolithic bilayer sheets (MBS) of hierarchically porous graphitic carbon (HPGC) and polymeric foam for use in salt-resistant and flexible solar steam generators is reported. The MBS-based self-floating solar steam generator shows outstanding solar desalination performance with a solar thermal efficiency of 83.2% (1-sun) and a high salt-rejection ratio (99.9%). Efficient solar thermal energy transformation is achieved by the versatile multi-functionalities of the MBS, including broad-spectrum solar light absorption, heat localization, and capillary action. Anisotropic wetting properties of hydrophobic HPGC and hydrophilic polyimide (PI) foam effectively prevent salt accumulation on the HPGC surface. The salt-resistant MBS enable long-term stability for solar desalination with actual seawater. Our laser-based photothermal method has potential in the development of high-performance solar thermal systems with substantial cost reduction by scalable production of multiscale hierarchically structured materials from micro-structured polymers.

Sunlight-Driven Continuous Flapping-Wing Motion.

Light-driven actuators that directly convert light into mechanical work have attracted significant attention due to their wireless advantage and ability to be easily controlled. However, a fundamental impediment to their application is that the continuous motion of light-driven flexible actuators usually requires a periodically switching light source or the coordination of other additional hardware. Here, for the first time, continuous flapping-wing motion under sunlight is realized through the utilization of a simple nanocrystalline metal polymer bilayer structure without the coordination of additional hardware. The light-driven performance can be controlled by adjusting the grain size of the upper nanocrystalline metallic layer or selecting metals with different thermodynamic parameters. The achieved highest frequency of flapping-wing motion is 4.49 Hz, which exceeds the frequency of real butterfly wings, thus informing the further development of sunlight-driven bionic flying animal robotics without external energy consumption. The flapping-wing motion has been used to realize a light-driven whirligig, a light-driven sailboat, and photoelectric energy harvesting. Furthermore, the flexible bilayer actuator features the ability to be driven by light and electricity, low-power actuation, a large deflection, fast actuation speed, long-time stability, strong design ability, and large-area facile fabrication. The bilayer film considered herein represents a simple, general, and effective strategy for preparing photoelectric-driven flexible actuators with target performances and informs the standardization and industrial application of flexible actuators in the future.