Superhydrophilic Copper Research Articles

High-Flux Steady-State Demulsification of Oil-In-Water Emulsions by Superhydrophilic-Oleophobic Copper Foams with Ultra-Small Pores Under Pressure.

3D superwetting materials struggle to maintain high-flux steady-state demulsification for oil-in-water emulsions because the accumulated oil within the material is difficult to discharge rapidly. The water flow shear force can swiftly remove the oil from the anti-fouling surface. In this study, by introducing nanofibers and carbon nanotubes and chemical modification, a superhydrophilic-oleophobic copper foam with pores of several micrometers is prepared, which can achieve a continuous demulsification process with steady-state flux over 57000 Lm-2h-1 for oil-in-water emulsions and rapid hydraulic-driven oil release under an additional pressure of 5kPa. Thanks to the ultra-small pores of the copper foam, the steady-state demulsification efficiency can be still maintained at over 97.5%. During the demulsification process, the accumulation of oil and surfactants within the copper foam can be maintained at low levels, achieving dynamic equilibrium. With the aid of second-stage superhydrophilic copper mesh, the demulsified oil-water mixtures can be rapidly separated. This high-flux, steady-state, and efficient demulsification process shows great potential for industrial applications.

Facile fabrication of superhydrophilic copper foam for rapid and efficient filtration of cationic dyes from water

Rapid and efficient separation of dyes from water is a formidable challenge due to the trade-off between separation selectivity and permeability. Here, a novel superhydrophilic copper foam (CF) enabling the rapid and efficient filtration of cationic dyes from water is reported. The fabrication involves brushing a coating consisting of attapulgite (APT), poly(vinyl alcohol) (PVA), TiO2 and glutaraldehyde (GA) onto copper foam and then heating. The obtained copper foam (CF-PVA/GA@APT/TiO2) is superhydrophilic and negatively charged with dye adsorption capability. The interconnected cage-shaped porous structure endows the foam with long tortuous permeation channels and large pore size. It is able to separate various cationic dyes with a separation efficiency reaching to 99.93 % and a permeation flux up to 1671 ± 189 L m-2h−1 under gravity. Furthermore, the CF-PVA/GA@APT/TiO2 can realize the selective separation and recovery of various cationic dyes from rhodamine B (RhB)-mixed dye solutions. Molecular dynamics-based computational modeling and experimental studies revealed that the interaction energy between the surface of CF-PVA/GA@APT/TiO2 and methylene blue (MB) is much stronger than that of the former and RhB, leading to adsorption of MB in the permeation channel, while RhB gradually migrates through the permeation channel and passes through the channel with water. The tortuous permeation channels of CF-PVA/GA@APT/TiO2 increase the contact area and absorption opportunities for cationic dye molecules on the surface, and its large pore size maintains the filtration flux. These properties provide the as-prepared foam with excellent potential applicability for industrial dye wastewater treatment.

Continuous and steady-state high-flux demulsification of oil-in-water emulsions by antifouling copper foam with composite superhydrophilicity-oleophobicity

Three-dimensional superhydrophilic materials hardly achieve continuous high-flux demulsification and separation for oil-in-water emulsions due to intrinsic oleophilicity leading to potential penetration of oil droplets through hydration layer and contamination on the surface over long-term separation processes. Constructing intrinsic oleophobic micro-regions on superhydrophilic surface can intensify anti-oil-fouling capacity for three-dimensional superhydrophilic materials. Herein, a composite superhydrophilic-oleophobic copper foam was prepared through co-deposition of aminated and fluorinated carbon nanotubes, skillfully introducing inherent oleophobic micro-regions on superhydrophilic interface to intensify anti-oil-adhesion capacity. Through a column technique, the modified copper foams achieved continuous demulsification of surfactant-stabilized and free oil-in-water emulsions without interruption for cleaning with high fluxes over 6000 and 10,000 L·m−2·h−1, and separation efficiencies over 95.1 % and 97.4 %, respectively. Various emulsions after demulsification transformed into immiscible oil–water mixtures, which can be quickly separated into pure oil and water at the aid of a second-step separation procedure by a superhydrophilic copper mesh. Importantly, the amount of recycled oil was consistent with that in feed emulsion during separation, indicating the accumulated oil in the copper foam could maintain dynamic equilibrium and a continuous and steady-state demulsification was achieved. The high-flux and continuous demulsification represents a significant breakthrough for superhydrophilic materials in the industrial application of oil–water separation.

Experimental study of a low-cost reversible thermal diode for advanced heat manipulation

A low-cost reversible thermal diode was fabricated by a copper tube loop incorporating a valve in the top channel for advanced thermal management. The inner surface of one vertical tube was treated to superhydrophobic, while that of the other vertical tube was modified to superhydrophilic and further loaded with a superhydrophilic copper mesh for water wicking. Furthermore, the valve in the top channel can behave as a switch to control the hot vapor flow between the two vertical tubes. Then, different heat powers from 5 W to 15 W were applied to investigate the rectification effect of the thermal diode under low (30 %), medium (50 %), and high (70 %) filling ratios (FR) of the working fluid. The results showed that its rectification ratio could exceed 2.8 with the help of the control valve at FR = 30 %. Furthermore, the rectification effect could be reversed by the valve without flipping the thermal diode. In reversible working mode, the reversed heat transport could reach twice of the forward heat transport at FR = 50 %. Therefore, owning to the reversible heat transfer capacity, this study can guide the advanced thermal diode design for unstable waste heat recovery, solar energy harvesting, building energy management, etc.

Robust and stable organic sulfonate sodium salt-coated superhydrophilic mesh for ultra-fast gravity-drive oil-water separation

Due to its special wetting behavior and high selectivity, super-wetting mesh is considered as an ideal candidate material for efficient separation of water/oil mixture. However, the oil-water separation mesh suffers from the problems of poor stability and durability, leading to the failure of the separation. In this paper, a robust and stable superhydrophobic/superhydrophilic copper mesh had been successfully prepared by decorating the copper mesh via the chemical grafting of the 3-thiol-propyl trimethoxysilane (KH590) and the subsequent reaction with 2-acrylamide-2-methylpropane-1-sulfonate sodium (AMPS). It showed that the KH590 condensation compound was tightly coated on the surface and the superhydrophobic copper mesh (SUCM) possessed excellent superhydrophobicity towards various liquid droplets with a WCA of higher 150° and a sliding angle lower 5°, while the superhydrophilic copper mesh (SICM) had promising anti-oil pollution property with WCA near 0°. The SUCM and SICM also had excellent acid and alkali resistance. The obtained SICM had preeminent separation efficiency higher 99% and extremely high permeability flux of 33,441 L·m−²·h−¹ for gravity-driven toluene-water separation, and possessed excellent recyclability even after 20 cycles. Moreover, the SICM could be used to separate the oil-water mixture of aqueous solution with different pH (pH=5/7/8) and aqueous sodium chloride solution with different concentrations (5%/25%/50%/saturated aqueous sodium chloride solution). In addition, the SICM had outstanding anti-abrasion mechanical stability. This work provided a simple and effective method for the preparation of special wettability materials with excellent acid/alkali resistance and mechanical stability, and promoted the practical application of oil/water separation mesh.

Effect of Biological Contamination of Copper Surfaces with Extreme Wettability on Their Antibacterial Properties

Bacterial health care-associated infections (HCAI) are one of the acute problems of modern healthcare. One of the promising directions for solving this problem is the development of materials that either have a bactericidal effect against HCAI pathogens or prevent the transmission of bacteria deposited on their surface by patients and staff contacts with such surfaces. In this work, the antibacterial effectiveness of copper contact surfaces with different wettability was investigated. Particular attention was paid to studying the effect on this efficacy of surface contamination by both human contact sweat and bacterial life-supporting substances, using a peptone solution as an example. Due to the high cost of copper, the possibility of replacing bulk copper material with less expensive sprayed copper-coated materials was also investigated. The test results showed that the bactericidal efficacy against Staphylococcus aureus strain of both control copper and superhydrophilic copper samples, as well as of sputtered copper films, is close to 100% and almost unchanged after contamination with peptone solution or sweat excretions. Superhydrophobic copper surfaces have less bactericidal efficacy, but due to the non-wettability effect and low cell adhesion to such surfaces, they remain uncontaminated longer and thus also promote reducing the transmission of infections through the touch surfaces made of them.

Synergistic effect of superhydrophilic skeleton decorated with hierarchical micro/nanostructures and graphene oxide on solar evaporation

Solar evaporation is considered as a sustainable and environment-friendly technology to produce the fresh water. However, the significant improvement in the solar evaporation efficiency is limited by the low energy utilization rate of evaporator, unreasonable design and/or complex manufacturing processes. Herein, the innovative solar vapor generator has been manufactured by the simple chemical oxidation and physical precipitation, consisting of the copper foam and graphene oxide (GO) as matrix. The copper foam skeleton of the innovative solar evaporator decorated with micro/nanostructure limits the heat to the evaporation interface for in-situ heating, effectively generating the vapor and minimizing the heat loss. The superhydrophilic structure and oxygen-containing groups of GO play a positive role in promoting the continuous wetting and water transport. The wetting state of unfilled pores provides sufficient space for the diffusion of vapor from the evaporation interface. Findings demonstrate that the evaporation rate and efficiency of superhydrophilic copper foam solar vapor generator deposited with 1.5 mg/mL GO (SHiCF-GO-1.5) are 1.25 kg/(m2·h) and 88.9% under 1-sun irradiation, respectively. The innovative solar evaporator makes full use of skeleton to expand solar absorption and evaporation interfaces to the whole 3D structure, playing a dominant role for enhancing solar evaporation efficiency.

Synergistic effect of mixed wettability of micro-nano porous surface on boiling heat transfer enhancement

In this work, a simple immersion technique was created to further enhance the pool boiling heat transfer performance of micro-nano copper foam by modifying its mixed wettability. The SEM images exhibit that the entirely-covered micro/nanostructures can be observed on the super-hydrophilic copper foam, while the hydrophilic-hydrophobic copper foam is covered with nanograss partially. The experiments indicated that the hydrophilic-hydrophobic copper foam showed the best heat transfer coefficient of the all sample surfaces at a high heat flux (>40 W/cm2), which can be as high as 4.15 W/cm2·K. Meanwhile, the critical heat flux (CHF) was measured as 108.32 W/cm2, which was 157.3% higher than that on the smooth surface, and 57%, 33.2% and 37.4% higher than that of untreated, super-hydrophilic, super-hydrophobic copper foams, respectively. Interestingly, due to the unique modification of the surface, the onset of boiling (ONB) on the sample was much reduced from 9 K to 0.5 K. These improvements are due to the increasing nucleation density, the reduced bubble departure diameter and the much shortened bubble period compared to other comparative samples. It is speculated that enhancement of the boiling heat transfer is attributed to the synergistic effect of improved bubble nucleation, the vapor escape, and the liquid replenishment on the designed sample with a mix wettability.

Underwater Superoleophobic and Underoil Superhydrophilic Copper Benzene-1,3,5-tricarboxylate (HKUST-1) Mesh for Self-Cleaning and On-Demand Emulsion Separation.

Surfaces with underoil superhydrophilic (UOSHL) and underwater superoleophobic (UWOHB) have great potential for on-demand emulsion separation. However, the fabrication of underoil superhydrophilic based on wetting thermodynamic principles is quite challenging. Several previous studies have shown that some sarcocarps are able to spontaneously absorb water to moisturize themselves and have a unique UOSHL ability. By mimicking this unique ability of the sarcocarp, an outstanding UWOHB and UOSHL membrane was prepared. We choose 2300 mesh stainless steel mesh (SSM) as the substrate, then grow Cu and Cu(OH)2 on SSM by a simple electrochemical method, and finally grow HKUST-1 crystals via a fast in situ growth method. The whole preparation process is simple, low cost, and does not require complex and long-term hydrothermal reactions. By growing HKUST-1 crystals, the prepared surface successfully achieved the required UOSHL and UWOHB properties. When the water droplets come into contact with the membrane under n-hexane, it will diffuse and can completely spread out in 2 s. The as-prepared membrane exhibits outstanding anti-fouling and self-cleaning properties for rapeseed oil and crude oil with high viscosity underwater due to the special wetting. By prewetting the surface with an appropriate amount of the dispersion medium, it can rapidly and efficiently on-demand separate different emulsions. The separation efficiencies of water-in-oil emulsions and oil-in-water emulsions are above 99.00 and 97.00%. With their outstanding performance in self-cleaning, on-demand emulsion separation, low cost, and fast preparation, the as-prepared UOSHL and UWOHB HKUST-1 meshes show excellent potential for treating oily wastewater in practical applications.

3D Solar Evaporation Enhancement by Superhydrophilic Copper Foam Inverted Cone and Graphene Oxide Functionalization Synergistic Cooperation.

Solar evaporation has become a promising and sustainable technique for harvesting freshwater from seawater and wastewater. However, the applicability and efficacy of solar evaporation need further improvement to achieve high production closer to theoretical limits in compact systems. A 3D (three-dimensional) hierarchical inverted conical solar evaporation is developed, which consists of a 3D copper foam skeleton cone decorated with micro-/nano-structures functionalized with graphene oxide, fabricated via easy and scalable wet oxidation, impregnation, and drying at room temperature. The proposed configuration empowers high-efficiency solar absorption, continuous liquid film spreading and transport, enhanced interfacial local evaporation, and rapid vapor diffusion through the pores. More notably, the 3D conical evaporator realizes thermal localization at the skeleton interface and allows evaporation to occur along the complete structure with unimpeded liquid and vapor rapid diffusion. The solar-thermal evaporation efficiency under 1-Sun is as high as 93% with a maximum evaporation rate per unit area of 1.71 kg·m-2 ·h-1 . This work highlights the benefits of synergistic cooperation of an easily scalable 3D hierarchical functiomicro-/nano-structured copper foam skeletons and functionalized graphene oxide for high-efficient solar evaporation of interest to numerous applications.

Numerical simulation study of oil–water separation based on a super-hydrophilic copper net

Green and environmentally friendly oil–water separation is an important technique for reducing environmental pollution. In this study, the oil–water separation effect of the super-hydrophilic copper net was optimized through numerical simulation and orthogonal experiments. To be specific, a super-hydrophilic copper net was prepared using the solution etching method to perform oil–water separation experiments, and a favorable oil–water separation effect was achieved. First, the influences of oil–water flow velocity, copper net mesh size, and surface wettability on the oil–water separation effect of the super-hydrophilic copper net were explored via single-factor experiments. The results showed that the oil resistance of the super-hydrophilic copper net degraded, and its oil–water separation effect became poor due to the increasing oil–water flow velocity, enlarged copper net mesh size, and reduced oil contact angle on the surface of the super-hydrophilic copper net. On this basis, the optimized oil–water separation parameters were obtained through orthogonal experiments. The optimized process parameters were as follows: velocity = 0.1 m/s, copper net mesh size = 30 μm, oil contact angle = 150°, and oil removal rate = 95.7%. Furthermore, the copper net was etched using sodium hydroxide and sodium persulfate mixed solution to prepare a 500-mesh super-hydrophilic copper net for the oil–water separation experiment and then the oil removal rate reached 96.4%. The study results provide a theoretical basis, method, and means for the practical application of super-hydrophilic copper nets.

Stable superhydrophobic and conductive surface: Fabrication of interstitial coral-like copper nanostructure by self-assembly and spray deposition

Water permeation is an important issue in both fundamental research and industrial applications. In this work, stable superhydrophobic copper surfaces were obtained by self-assembly and spray deposition on cotton fabrics. Scanning electron microscopy revealed that micro/nano dual-scale coral-like structures were established by the stacking of copper nanoparticles, thus forming a stable Cassie model for superhydrophobic feathers. The water contact angle of the surface was 161°, while the slide angle was as low as 3°. Chemical bonds were formed between substructures and copper nanoparticles by molecular grafting, which improved its mechanical stability, since the surface was verified to maintain a large contact angle after long-distance abrasion and folding. Compared with the superhydrophilic copper surface, the superhydrophobic coating showed better corrosion resistance in 3.5 wt% NaCl solution and artificial sweat. Combined with the inherent conductivity of copper, fabrics have potential applications in the new generation of advanced textiles.

Fabrication of super-wetting copper foam based on laser ablation for selective and efficient oil-water separation

Oil pollution has caused damage to the ecological environment and human health, which cannot be ignored in industrial production and marine economic. It is very vital to explore a simpler and easier to manufacture oil-water separation method. In this work, the super-wetting copper foam with superhydrophobicity or superhydrophilicity on was fabricated based on low-cost nanosecond laser ablation combined chemical modification. The surface of copper foam was covered with fluffy microstructures and smaller nanoparticles after laser ablation, which greatly enhances the hydrophobicity, with a maximum contact angle of 156°. The droplet could rebound many times after being compressed in a cake shape on the superhydrophobic surface but spread rapidly on the superhydrophilic surface. Analysis of chemical composition verified the fluorine-containing long-chain greatly reduces surface energy, while the oxygen group of graphene oxide is the opposite. Based on the oil permeability of the superhydrophobic copper foam and the water permeability of the superhydrophilic copper foam, the separation of heavy oil and light oil can be selectively achieved. The separation efficiency of different oil-water mixtures could be higher than 99%, and the recyclability was better after multiple separations. It provides a convenient and selective way for oil-water separation.

Solar-driven thermal-wind synergistic effect on laser-textured superhydrophilic copper foam architectures for ultrahigh efficient vapor generation

Solar-driven vapor generation is a sustainable and environmentally friendly method for water purification. Despite recent progress on photothermal steam generation, the rate of vapor generation remains low. Here, we enhance the vapor generation rate by combining solar-driven thermal and wind effects on a femtosecond-laser-textured superhydrophilic copper foam surface. Significant solar power can be absorbed and transformed into heat on the treated surface. This solar power can also be converted into electric power to generate wind to further accelerate steam generation. The upper superhydrophilic foam surface facilitates the continuous supply of water. A pre-wetted polyurethane sponge minimizes heat loss by preventing direct contact between the heated foam and bulk water. The as-prepared evaporator achieved a water evaporation rate of ∼7.6 kg m−2 h−1 under one sun irradiation (1 kW m−2) at a wind speed of 3 m s−1. This is a promising technology for enhancing water evaporation rates in seawater desalination and wastewater treatment applications.

Superhydrophilic Composite Structure of Copper Microcavities and Nanocones for Enhancing Boiling Heat Transfer

AbstractA type of high‐efficiency boiling heat transfer (BHT) interfaces based on superhydrophilic copper microcavity and nanocone (CMN) composite structure are reported. In principle, these microcavities are efficient nucleation sites, facilitating decreasing surface superheat required for onset of nucleation boiling (ONB) and enhancing heat transfer coefficient (HTC); discrete nanotips facilitate the departure of boiling bubbles at smaller scale; shallow microcavities with depth of a few micrometers can avoid excess interface thermal resistance; and the superwetting effect of structure itself helps improve critical heat flux (CHF). Through exploring morphology, wettability, boiling mass and heat transfer properties of CMN structures varied with growth time, an optimal interface is obtained with 142% enhancement in the maximum HTC, 64% enhancement in CHF, and 33% decrease in the ONB superheat as compared to the flat copper surface. Meanwhile, combined experiments and theoretical analyses also clarify why the in situ growth of CMN structures on the copper surface can effectively enhance BHT and why the BHT enhancement effects become worse as the growth time of CMN structure increases. This work not only widens the application scope of superwetting surfaces but offers new insight how to rationally design superhydrophilic micro‐ and nanostructures so as to achieve more efficient BHT.

An Experimental Investigation on Thermal Performance of Ultra-Thin Heat Pipes with Superhydrophilic Copper Braids

This study investigated the thermal performance of ultra-thin heat pipes (UTHPs). The total thickness of the heat pipe was 1 mm and the novel wick structure was copper braids modified to be superhydrophilic with higher capillary ability. This paper is divided into three parts, each focusing on the effect on the heat transfer performance of UTHPs, including the wettability of the wick, the filling ratio (FR), and the variation of sectional lengths. The experimental results indicate that the superhydrophilic wick structure improves the thermal performance of UTHPs, and that the FR of 16.4% results in the best thermal performance of UTHPs. Furthermore, the sectional lengths affect both the thermal resistance and the maximum heat transport capacity. The results indicate that the thermal resistance of UTHPs increases for longer adiabatic lengths but slightly decreases for longer condenser and evaporator lengths. However, because the maximum heat transport capacity is influenced by the effective length of the heat pipe, it is degraded when the adiabatic length or the condenser and evaporator length increases. An UTHP of 55-mm effective length with superhydrophilic copper braids yields thermal resistance around 0.3 /W and the best heat transport capacity of 26.3 W.

Condensation and Wetting Behavior on Hybrid Superhydrophobic and Superhydrophilic Copper Surfaces

Abstract A novel hybrid superhydrophobic and superhydrophilic copper surface was fabricated using a lift-off process to integrate the benefits of dropwise and filmwise condensation together. The superhydrophilic surface was comprised of microflower like CuO and nanorod Cu(OH)2 with a diameter in the range of 200–600 nm and the superhydrophobic surface was fabricated by chemical modification with Cytop on the hierarchically structured surface of CuO/Cu(OH)2. Wetting condition effect on the hybrid surface was investigated experimentally with a high-speed camera attached to a microscope and an environmental scanning electrical microscope (ESEM). Out-of-plane droplet jumping motion on superhydrophilic region and gravity effect on the droplet motion were examined. Experiment results showed that effective heat transfer coefficients of hybrid superhydrophobic and superhydrophilic surfaces were improved as compared with those of pure superhydrophobic surface. Comparison results between two hybrid surfaces with 2 and 4 mm pattern pitches indicated that the distance reduction between two neighboring superhydrophilic areas can enhance the condensation performance because short distance can promote the microcondensate coalescence and droplets removal.

The Dependence and Evolution Mechanism of Surface Structure of Electrodeposited Ni Films on Wettability

Porous metal films directly electrodeposited by using hydrogen bubbles as template have attracted widely attentions. However, the formation and evolution mechanism of pores are unclear. Lots of hydrogen bubbles are produced during electrodeposition, which will affect the surface structure of porous metal films. Wettability is an intrinsic property to adjust bubble separation and expected to change surface structure of electrodeposited metal film. In the paper, electrodeposited Ni was used as a model, and the effects of wettability on bubble characteristics and surface structure of Ni films were studied. The formation mechanism of pores was analyzed based on COMSOL simulation. The results indicated that the break-off diameter of bubbles decreased with the addition of sodium dodecyl sulfate (SDS) due to the decrease of contact angle and surface tension. Therefore, the pore size can be reduced. On superhydrophilic copper foil, rough Ni films without uniform pores were electrodeposited. On compact copper foil with the contact angel of 76o, honeycomb Ni films were obtained. On superhydrophobic copper foil, irregular Ni films with weak adhesion were electrodeposited and surface peeling happened easily. It was confirmed that pore formation was related to the protrusion growth of electrodeposited Ni.

Wettability effect on pool boiling heat transfer using a multiscale copper foam surface

To improve thermal performance, the wettability effect on pool boiling heat transfer using copper foam is experimentally studied. A surface oxidation and chemical modification method is employed to modify copper foam surface’s wettability. After wettability treatment, the copper foam surface is covered with nanosheet. The average contact angle on 50 PPI super-hydrophobic and super-hydrophilic copper foam surface is 148.7° and nearly 0°, respectively. An experimental platform regarding the thermal performance of subcooled pool boiling heat transfer for deionized water on copper foam with a modified wettability surface is conducted. Results showed that the super-hydrophilic copper foam’s surface achieves better boiling heat transfer performance in a medium- or high-heat flux region (q ≥ 20 W⋅cm−2), while super hydrophobic copper foam surface shows a better performance when q < 20 W⋅cm−2. The pool boiling enhancement of wettability-modified surface has been verified compared with flat surface from public work. The maximum heat transfer coefficient in this experiment reaches 19,238 W⋅m−2⋅K−1 for super-hydrophilic surface (50 PPI, 2 mm thickness) at a heat flux of 96 W⋅cm−2. The bubble dynamic behavior during pool boiling is observed through a high-speed camera. The visualization showed that the shape, size and number of bubbles on super-hydrophilic copper foam surface during pool boiling are different from that on super-hydrophobic copper foam surface due to different adhesion force and surface tension. As copper foam thickness increases, more bubbles are trapped in the copper foam. By analyzing the heat transfer mechanism in copper foam, it is deduced that the specific copper foam structure conveys a larger heat transfer area, and meanwhile, the micro-nanostructure provides an abundance of nucleation sites. Moreover, a super-hydrophilic surface could promote liquid replenishment for the copper foam. Therefore, wettability-modified copper foam shows great promise in thermal management.

Study on axial wetting length and evaporating heat transfer in rectangular microgrooves with superhydrophilic nano-textured surfaces for two-phase heat transfer devices

Advanced thermal management solutions for various applications in energy systems have promoted the developments of novel hybrid wicks for two-phase heat transfer devices (TPHTD). In this study, a novel micro-nano hybrid wick combined rectangular microgrooves with superhydrophilic copper hydroxide nano-textured surfaces is developed. Comparative experiments on the axial wetting lengths, evaporating flow characteristics and evaporating heat transfer performance are systematically conducted for different microgrooves-based wick samples, i.e., the pristine rectangular microgrooves (RMs) and rectangular microgrooves with superhydrophilic nano-textured surfaces (RMSNSs). The distilled water and ethanol are both used as working fluids. The experimental results indicate that the RMSNSs wick produces remarkable increases in axial wetting lengths compared to the pristine RMs wick. Under the unheated condition, the total wetting length (Lt) of water in RMSNSs is more than 4 times of that in RMs. Under the same condition of heat flux, the Lt of RMSNSs is also distinctly larger. The improved axial wetting characteristics can be attributed to the effect of surface wettability enhancement, which have a critical influence on the evaporating heat transfer. The sample temperature of RMSNSs is much lower at each given heat flux and the decrement is more than 15 °C. The maximum incremental ratio of heat transfer coefficient can approach 100%. The enhanced evaporating heat transfer highly depends on the significantly increased thin liquid film area. Furthermore, a theoretical model is presented to facilitate the understanding on axial wetting and heat transfer enhancements effect of RMSNSs. The proposed model is applicable and satisfactorily accurate to predict the axial wetting lengths for microgrooves-based wick sample under the evaporating heat transfer condition. This study provides an in-depth insight into the enhanced axial flow and heat transfer characteristics of micro-nano hybrid wick incorporating microgrooves and nanostructures, and consequently can facilitate the further optimization design of microgrooves-based wick for advanced TPHTD. It is believed that this superior hybrid wick with advantages of facile and rapid fabrication is highly promising in the applications of heat energy transfer, conversion and management.