Superhydrophilic State Research Articles

Analysis of time-dependent hydrophobic recovery on plasma-treated superhydrophobic polypropylene using XPS and wettability measurements

In specific applications like ice-repellent coatings or membrane separation technology, wettability is a key parameter affecting the applicability of commodity polymers. This study presents a technique to fine-control the wetting properties of a hierarchically structured polypropylene surface, enabling the transition between superhydrophobic and superhydrophilic states. To demonstrate the tunability of the wetting properties of polypropylene (PP) substrate, we prepared in a consecutive way superhydrophobic (advancing contact angle (CAadv) of 152°) and superhydrophilic (CAadv of 0°) material by solvent-treatment and mild air plasma treatment. The optimal plasma treatment parameters to achieve superhydrophilic wetting behaviour, which is stable for at least one week of storage in air was also explored. Water contact angle measurement and X-ray photoelectron spectroscopy were used to monitor the time dependency of hydrophobic recovery on a hierarchically structured PP surface. With a simple model considering structural and wetting parameters, we characterized the droplet spreading behaviour of plasma-treated roughened surfaces, which exhibited superhydrophilic wetting behaviour with equilibrium CAadv of nearly 0°. The proposed model, which aligns well with experimental data, can be used to compare the droplet spreading behaviour of plasma-treated roughened surfaces.

Photo-induced time-dependent controllable wettability of dual-responsive multi-functional electrospun MXene/polymer fibers

Switchable wettability potential in smart fibers is of paramount importance in various applications. Light-induced controllable changes in surface wettability have a significant role in this area. Herein, smart waterborne homopolymer, functional copolymer with different polarity and flexibility, and multi-functional terpolymer particles containing a time-dependent dual-responsive acrylated spiropyran, as a polymerizable monomer, were successfully synthesized through eco-friendly single-step emulsifier-free emulsion polymerization. Presence of 10 wt% of butyl acrylate and dimethylaminoethyl methacrylate relative to methylmethacrylate as functional comonomers decreased the Tg of the samples almost 20 ℃ and increased their polarity. The optical properties of the particles were investigated, and the UV–vis and fluorescence spectroscopy results showed that not only polarity and flexibility of the polymer chains may have a positive effect on improving the optical properties, but also the simultaneous presence of functional groups has a synergistic effect. The smart polymer particles with flexibility and polarity features exhibited higher absorption and emission compared to other samples. Inspired by these findings, multi-functional smart polymer fibers were prepared using the electrospinning method. The smart multi-functional electrospun fibers containing few-layer Ti3C2 MXenes were synthesized to improve the fibers’ properties and change the surface wettability due to the hydrophilic functional groups of MXene. Field-emission scanning electron microscopy images displayed the successful preparation of few-layer MXenes. Smooth and bead-free fibers with bright red fluorescence emission under UV irradiation were shown using fluorescence microscopy. The study on the surface wettability of fibers revealed that UV and visible light irradiation induced reversible time-dependent changes in the wettability of the smart multi-functional MXene/polymer electrospun fibers from hydrophobic to hydrophilic, reaching a water contact angle of 10° from an initial water contact angle of 100° under UV light and also changing to superhydrophilic state with passing time. Upon visible light exposure, the fibers returned to their original state. Furthermore, the fibers demonstrated a high stability over five alternating cycles of UV and visible light irradiation. This study shows that the fabrication of time-dependent smart fibers, utilizing the flexibility and polarity in the presence of MXenes, significantly improves and controls surface wettability changes. The outstanding dynamically photo-switchable wettability of these fibers may offer exciting opportunities in various applications, especially in the separation of oil from water contaminants.

Simple and reversible method to control the surface energy of ITO branched nanowires for tuning wettability of micro/nanoscale droplets

Reversible control of hydrophobic and hydrophilic surfaces has gained attention due to their potential applications in microfluidic devices, membranes for electrochemical cells, and sensors. While external stimuli such as temperature and electric field can regulate surface properties, they cannot be selectively applied to specific regions, which limits the patterning of areas with different surface energies. Here, we present a simple and reversible method for converting hydrophobic and hydrophilic properties through surface treatments involving nonpolar (−CFx) or polar groups (–OH) on indium tin oxide branched nanowires (ITO BRs). The formation of nonpolar groups results in superhydrophobic surface. Subsequent ultraviolet ozone treatment, using a shadow mask, induces the exposed area to transition into a superhydrophilic state, while the unexposed area retains superhydrophobicity. This demonstrates the potential for selective-area surface energy patterning. Furthermore, we investigate the wetting behavior of nanoscale Ag nanoparticles (NPs) on surface-modified ITO BRs. It is observed that size and shape of Ag NPs depend on the surface energy of ITO BRs. Consequently, controlling the surface energy leads to the formation of unique geometric structure of Ag NPs, enhancing plasmonic light absorption and scattering at specific resonant wavelengths.

Wettability of anatase TiO2 surface: Effect of niobium doping

The effect of niobium doping on the hydrophilic behavior of anatase TiO2 surface was demonstrated on a series of x-Nb-TiO2 nanocoatings with dopant concentrations in the range of 0.0 - 1.0 at.% Nb. Thin films prepared on glass substrates from sols by dip-coating were characterized by tensiometric, work function and isoelectric point measurements along with FT-IR spectroscopy in situ method. Using macroscopic and microscopic techniques, it was found that, at low doping level, it is the functionalization of the anatase surface with niobium ions that leads to a drastic change in its surface acid-base as well as electronic properties and, as a consequence, to a sharp increase in the initial surface hydrophilicity. The rearrangement in the hydroxyl‑hydrated layer with the formation of additional hydroxyl groups as a result of surface functionalization has an increased effect on wettability only at low levels of niobium inclusion, whereas with increasing dopant content the electronic factor plays a significant role on the properties of titanium dioxide, including its wettability. The kinetic dependencies of the photoinduced superhydrophilic conversion for all Nb-doped titanium dioxide surfaces were obtained and discussed in terms of proposed mechanism. Both the initial hydrophilic state and the initial rate of photoinduced hydrophilic conversion depend on the Nb concentration in titanium dioxide, while the final UV-induced superhydrophilic state is achieved for all Nb-doped TiO2 regardless of the dopant content.

A novel epoxy-based self-healing robust superhydrophobic coatings for oil/water separation

Low durability greatly limits the practical application of superhydrophobic coating. In this study, we report a method of employing low surface energy materials and chemically reactive epoxy groups that possess strong adhesion on substrates in one system to solve the durability issue. A branched epoxy with dangling long polydimethylsiloxane (PDMS) tail was first synthesized through a thiol-Michael addition reaction. After curing, this coating exhibited superhydrophobicity with the contact angles (CAs) of 162.8 ± 1.0° and excellent durability towards strong acid (pH = 1.0), organic solvents as well as thermal treatment (150 °C, 24 h). Notably, the CAs of this coating could maintain above 150° after 80 times of sandpaper abrasions, 100 times of tape-peeling, and 240 min of ultrasonic treatment, respectively. More importantly, the coating could spontaneously revert to a superhydrophobic state at room temperature after being plasma-treated to a superhydrophilic state. The coating fabric was utilized to separate the mixture of oil/water and the efficiencies for blend oil, corn oil, and soybean oil were found to be 97.7 ± 0.4 %, 98.2 ± 0.5 %, and 98.7 ± 0.3 %, respectively. This work provides a novel strategy to create a fluorine-free, self-healing, and robust superhydrophobic coating.

Photothermal superhydrophobic surfaces with dual self-healing capabilities

In this study, superhydrophobic coatings with dual self-healing functions were constructed by spraying fluorosilane-modified SiO2 aerogel powders and multi-walled carbon nanotubes on composite films composed of polycaprolactone and epoxy resin. The synergy between the thermally healable polycaprolactone/epoxy resin layer and the photothermal effect of the multi-walled carbon nanotubes allows the coating to repair scratches on the coated surface under light. The porous surface, composed of fluorinated SiO2 aerogel powders and multi-walled carbon nanotubes, provides surface roughness while acting as a storage site for low surface energy healing agents, creating the conditions for surface chemical energy repair. After oxygen plasma etching, the samples were exposed to a solar intensity for 30 min to restore the superhydrophilic state to the superhydrophobic state. The scratches on the sample surface of about 80 μm can be repaired after 20 min of light exposure. The dual healing of chemical energy and the rough structure of the material surface is expected to solve the problem that superhydrophobic surfaces are prone to damage and fail in practical applications. In addition, the material has excellent antifouling and self-cleaning properties. In synergy with the self-healing properties, the material is expected to be recyclable in the long term.

Tailoring polycarbonate surfaces for improved Ge film adhesion: The role of plasma treatments in 50:50 O2/Ar atmospheres

Polycarbonate (PC) substrates were exposed to plasma environments consisting of a 50:50 mixture of oxygen and argon, and were subsequently coated with germanium (Ge) films grown via sputtering. The hydrophilicity of the PC surfaces was tailored by ion bombardment with energy levels ranging from 50 to 300 eV, which led to a reduction in water contact angles from a native 80° to a superhydrophilic state. Analyses of chemical composition and structure of the PC were performed using X-ray Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy in Attenuated Total Reflectance geometry (FTIR-ATR), and then correlated to the adhesion of the Ge thin films. Optimal adhesion of the Ge films was achieved by bombarding the PC with ions at energies between 100 and 200 eV, activating the polymer surface while avoiding photodegradation as confirmed by chemical analysis. We report an efficient method for achieving superhydrophilicity of PC within a short treatment time of 60 s that can be effectively integrated in diverse vacuum applications.

Durable anti-fog micro-nano structures fabricated by laser ablation of aluminum film on resin/glass

This study presents a technique for processing transparent glass and resin substrates using a low-cost laser marker to create a micro-nano-structured surface with exceptional anti-fog properties. The approach involved depositing an aluminum (Al) film on the transparent substrates as an absorbing layer, followed by rapid laser marker ablation. This ablation process effectively removed the majority of the Al film, resulting in the formation of hierarchical hillock-hollow micro-structures and the dispersion of Al-based nano-particles throughout the surface. The resulting structure on resin glasses demonstrated anti-fog performance even after 629 days storage in the laboratory, which marked the longest antifog record. It exhibited impressive antifog property without visible degradation for the first 9 months, which though degraded substantially afterwards. Furthermore, the micro-nano structure played a key role in reducing the contact angle of the surface. The contact angle experienced a significant reduction from a value of 64° for the control resin to 6.9° for the treated resin, while it was reduced from 44° for the control glass to 0° for the treated glass, indicating superhydrophilicity. This 0° superhydrophilic state persisted for a period of 25 days.

Robust and flexible polyester fiber membrane with under-liquid dual superlyophobicity for efficient on-demand oil-water separation

Functional materials with under-liquid dual superlyophobicity have generated a great deal of concern from researchers due to their switchable separation ability oil-water mixtures and emulsions. Conceptually, under-liquid dual superlyophobicity is a Cassie state achievable under-liquid through the synergy of an under-liquid double lyophobic surface and the construction of a highly rough surface. However, obtaining an under-liquid dual superlyophobic surface remains difficult due to its thermodynamic contradiction and complex surface composition. Herein, we successfully prepared a functional coating by modifying the mixture of cellulose nanocrystals (CNCs) and nano-TiO2 with perfluorooctanoic acid (PFOA) via a simple method, then obtained a polyester fiber membrane with under-liquid dual superlyophobicity by roll coating method. The surface wettability of the polyester (PET) membrane was altered, transforming it from the original under-water oleophobic/under-oil superhydrophilic state to the under-water superoleophobic/under-oil superhydrophobic state after coated. The resulting membrane was applied to separate oil and water on-demand. The coated PET membrane exhibited high separation efficiency (>99 %) and high separation flux, effectively separating immiscible oil-water systems as well as oil-in-water and water-in-oil emulsions. The coated PET membrane also demonstrated the ability to perform alternate separation of oil-water mixtures through wetting, washing, and rewetting cycles, with repeated processes up to 10 times without significant reduction in separation efficiency. Furthermore, compared with the previous works, our approach offers a simpler and more convenient method for constructing under-liquid dual superlyophobic surface, making it more suitable for continuous corporate production. This study may provide inspiration for the production and application in large-scale of under-liquid dual superlyophobic membranes.

Effect of Surface Wettability on Nanoparticle Deposition during Pool Boiling on Laser-Textured Copper Surfaces

Prior studies have evidenced the potential for enhancing boiling heat transfer through modifications of surface or fluid properties. The deployment of nanofluids in pool boiling systems is challenging due to the deposition of nanoparticles on structured surfaces, which may result in performance deterioration. This study addresses the use of TiO2–water nanofluids (mass concentrations of 0.001 wt.% and 0.1 wt.%) in pool boiling heat transfer and concurrent mitigation of nanoparticle deposition on superhydrophobic laser-textured copper surfaces. Samples, modified through nanosecond laser texturing, were subjected to boiling in an as-prepared superhydrophilic (SHPI) state and in a superhydrophobic state (SHPO) following hydrophobization with a self-assembled monolayer of fluorinated silane. The boiling performance assessment involved five consecutive boiling curve runs under saturated conditions at atmospheric pressure. Results on superhydrophilic surfaces reveal that the use of nanofluids always led to a deterioration of the heat transfer coefficient (up to 90%) compared to pure water due to high nanoparticle deposition. The latter was largely mitigated on superhydrophobic surfaces, yet their performance was still inferior to that of the same surface in water. On the other hand, CHF values of 1209 kW m−2 and 1462 kW m−2 were recorded at 0.1 wt.% concentration on both superhydrophobic and superhydrophilic surfaces, respectively, representing a slight enhancement of 16% and 27% compared to the results obtained on their counterparts investigated in water.

Patternable, high-precision, controllable wettability copper layers for 3D resin-based weather-resistant electronics and 3D liquid manipulation.

The realization of 3D patterned metal layers with manipulable surface wettability has significant potential, especially in integrating microelectronics with weather resistance and multifunctional liquid manipulation. However, developing a facile and efficient method to bring it to fruition remains a great challenge. In this work, we proposed a novel 3D selective metallization strategy that combines stereolithography 3D printing with laser-induced selective metallization (LISM). Utilizing 355 nm UV or 1064 nm lasers, this strategy can prepare 3D conductive copper patterns (or circuits) with controlled wettability on various 3D-printed resin parts. The copper layer surface prepared via LISM formed microstructures similar to the papillae on the surface of a lotus leaf, and it spontaneously exhibited superhydrophobicity (156.6°) after aging in the air at room temperature. Superhydrophobic 3D circuits with self-cleaning, corrosion-resistant, and anti-condensation performance were successfully fabricated. By further treating the copper layer with a 355 nm UV laser, we realized the transformation of the superhydrophobic copper layer to a superhydrophilic state, enabling us to prepare high-precision superhydrophilic patterns or channels. A 3D self-driven flow channel was fabricated to successfully realize 3D liquid manipulation and small-scale chemical experiments.

Construction of superhydrophobic surfaces with different water adhesion on the low-temperature steels by picosecond laser processing

Manufacturing superhydrophobic metallic surfaces with desired water adhesion for intended applications such as anti-icing and microdroplets transportation remains a grand challenge. Herein, we demonstrated the fabrication of the superhydrophobic surfaces with different water adhesion on the low-temperature steels including DH36, EH40 and FH36 steels via combined strategies of picosecond laser processing and room-temperature vacuum processing. The laser processing could regulate the dimension of the micro/nanostructures on the low-temperature steel surfaces and the vacuum processing controlled the surface chemical compositions of the laser-processed surfaces, leading to the transition of wetting behaviors from the superhydrophilic states, then to the superhydrophobic Wenzel's states with strong water adhesion and finally to the superhydrophobic Cassie-Baxter's states with weak water adhesion. The superhydrophobic surfaces with the Wenzel's states showed great potential in non-destructive and selective transportation of water droplets, while those with the Cassie-Baxter's states exhibited promising anti-icing performance as well as desirable corrosion, impact, and erosion resistance. This work provides an effective, pollution-free, and stable route for controlling the superwettability of the low-temperature steel surfaces and could find promising applications in surface modifications of metals and alloys.

Triple microenvironment modulation of zeolite imidazolate framework (ZIF) nanocages for boosting dopamine electrocatalysis

Multiple microenvironmental modulation of zeolite imidazole framework-8 (ZIF-8) is expected to solve the long-term intractable problem of low sensitivity in electrochemical sensing. Herein, the metal phthalocyanines with different central ions (PcM, M = Fe, Co, Ni and Cu) were introduced into ZIF-8 by in-situ synthesis method. Then, the hollow composite nanomaterials, HZIF-8/PcFe and HZIF-8@PcFe (HZIF-8, i.e., hollow ZIF-8) with different TA (tannic acid) coating thicknesses (∼11 nm and ∼33 nm) were successfully fabricated by carefully designed polyphenol-mediated modulation (PMM) strategy. Next, the HZIF-8@PcFe electrochemical sensor was constructed for selective and sensitive analysis by selecting dopamine (DA) as the analyte. The TA coating (superhydrophilic state), PcFe (redox properties) and hollow MOF cavity (faster mass transfer) was used as the triple microenvironment modulation of ZIF-8 to enhance the electrocatalytic performance. Under the optimum conditions (pH = 8.0), the linear correlations of 0.3 to 200 μmol/L was obtained for the peak current response, with a detection limit of 0.1 μmol/L (S/N = 3, i.e., Signal/Noise = 3). Meanwhile, the HZIF-8@PcFe electrochemical sensor exhibited excellent interference selectivity, reproducibility and stability, which enabled it to detect low abundance DA in real samples. And the F-test (homogeneity test of variance) and t-test (student's t test) statistical analyses were employed to enhance the accuracy of the actual samples' detection. This work will enlighten researchers working in the field of porous framework composites and open up new paths for the development of hollow MOFs hybrid materials in electrochemical sensing.

Influence of atmospheric pressure plasma modification on surface properties of aluminum alloy substrate and its interfacial adhesion strength with electrodeposited nickel coating

In the domain of electrodeposited coating applications, the interfacial bonding strength between substrate and Ni-based coatings plays a critical role in determining coating quality and service life. This study investigates the impact of surface physicochemical properties of aluminum alloys on the interfacial bonding strength with electrodeposited nickel, employing a nitrogen/air atmospheric pressure plasma operating at 10 W to modify the substrate surface. The surface microstructure of the substrate remains unaltered following plasma treatment, as evidenced by SEM and AFM images. However, XPS and FTIR-ATR analyses reveal a reduction in carbon content and an increase in polar hydrophilic functional groups, imparting hydrophilicity to the substrate surface. Notably, air plasma treatment proves more effective in modifying the aluminum alloy substrate compared to nitrogen plasma, leading to a super-hydrophilic state with a contact angle of 4.06°. Nano-scratch tests demonstrate a 13.92 % increase in interfacial adhesion strength of Ni-based coatings due to air plasma modification, reaching 14.16 N. This study underscores the considerable potential of plasma treatment techniques to significantly enhance the interfacial adhesion between substrate and electrodeposited nickel, thus presenting promising applications in novel electrodeposited coatings and related fields.

On the Corrosion Properties of Aluminum 2024 Laser‐Textured Surfaces with Superhydrophilic and Superhydrophobic Wettability States

AbstractIn this work, the mechanism of the corrosion behavior of laser‐treated aluminum is studied. Two different laser techniques are used to fabricate the samples, direct laser interference patterning (DLIP) and direct laser writing (DLW), using nanosecond laser sources. The DLIP treatment uses a two‐beam optical configuration producing line‐like periodic structures. The DLW technique is employed to produce non‐periodic structures on the Al‐surface with the same cumulated fluences as in DLIP. The surface topography is analyzed by confocal microscopy, and the formation of oxide layers is investigated by scanning electron microscopy of cross‐sections produced using a focused ion beam. Wetting measurements performed on the laser‐treated samples exhibit a contrasting behavior, leading to either superhydrophobic or superhydrophilic states. In the case of the DLIP treatment, the static water contact angle is increased from 81° up to 158°, while for DLW, it decreases to 3°. Electrochemical tests demonstrate a decreased corrosion rate after laser treatment. Additionally, findings indicate no correlation between wettability and corrosion reduction. Therefore, the improvement in corrosion resistance is mainly attributed to the oxide layer formed by laser treatment. Although similar corrosion rates are achieved for both treatments, surfaces produced with DLIP can be beneficial when additional surface properties are required.

UV Resistance of Super-Hydrophobic Stainless Steel Surfaces Textured by Femtosecond Laser Pulses

The loss of spontaneous liquid repellency on the surface of AISI 304 stainless steel under UV irradiation has been investigated depending on the textures formed by femtosecond laser pulses using Owens–Wendt plot analysis. Laser-induced periodic surface structures (LIPSS) have shown less liquid repellency compared to microgrooves. The polarity of the super-hydrophobic non-polar layer increased under UV irradiation to a super-hydrophilic state. The rate of this transition is determined by the surface topography and was faster for LIPSS compared to the bihierarchical textures formed by LIPSS in combination with microgrooves. The applicability of the Owens–Wendt approach for the numerical comparison of the achievable liquid repellency of textured surfaces in the Cassie state and the degree of polarity reversal of the hydrophobic layer was shown.

In-situ electrostatic self-assembly superhydrophilic UiO-66-NH2@h-PPS membranes for highly efficient oil-water emulsion separation

Highly efficient treatment of oil-water emulsions in severe environments (organic solvents, strong acids) is recognized as a challenging subject. Polyphenylene sulfide (PPS) is an ideal membrane material with superior thermal stability as well as chemical resistance that is expected to settle this challenge. However, the hydrophobicity of PPS (h-PPS) membrane inherently prevents its efficient treatment of oil-in-water (O/W) emulsions. In this study, superhydrophilic modification of PPS substrates was achieved by in situ electrostatic self-assembly of hydrophilic Zr-MOFs to obtain UiO-66-NH2@h-PPS membranes. The introduction of UiO-66-NH2 crystals constructed the micro/nanoscale hierarchical structure for the substrate, which transforms the PPS substrate from a hydrophobic to a superhydrophilic state (water droplets require only 0.6 s to be completely immersed in the membrane). Meanwhile, the UiO-66-NH2@h-PPS membranes gain under-water superhydrophobicity (the under-water oil contact angle exceeds 150° for toluene, hexane, dichloromethane, and carbon tetrachloride, of which toluene reaches 163.1°), thereby improving wettability selectivity and decreasing oil adhesion, permitting the fabricated UiO-66-NH2@h-PPS membranes to effectively separate different types of O/W emulsions. The UiO-66-NH2@h-PPS membranes acquire excellent permeate fluxes (for the surfactant-free toluene-in-water emulsion, it reaches up to 7638.1 L m−2 h−1) and separation accuracy (99.1% oil rejection). Moreover, the UiO-66-NH2@h-PPS membrane exhibited outstanding harsh environment resistance. Interestingly, the combination of UiO-66-NH2 and h-PPS substrate was applicable to degrade the organic compound in water, and the degradation efficiency of the methylene blue achieved 85.7% under visible light within 120 min. In summary, loading Zr-MOFs onto h-PPS substrates provides a novel strategy for the efficient treatment of wastewater under complex conditions with great potential for practical applications.

Fabrication of fluorine-free pH-responsive functionalized mesh via thiol-ene click chemistry for oil-water separation

pH-responsive materials with switchable wettability provide a novel strategy for oil-water separation applications. The thiol-ene click chemistry method was used to fabricate pH-responsive stainless-steel meshes (SSM) by grafting long-chain alkanes with carboxyl (COOH) and methyl (CH3) groups onto the SSM surface. The pH-responsive SSM showed excellent separation efficiency (>97 %) in both superhydrophobic and superhydrophilic states, which was unaffected by the presence of NaCl in the mixed solution. The pH-responsive SSM demonstrated a fast response within 3 s and a wide pH range after pre-wetting in an alkaline solution (pH spike) due to the presence of long carbon chains containing COOH and CH3 groups. Moreover, the mesh underwent antifouling, ultraviolet light (UV) resistance, and mechanical resistance tests, showing excellent durability and stability. The water contact angle (WCA) remained higher than 130° after 24 h of UV exposure and six rounds of wear experiments. Furthermore, the oil-water separation efficiency remained above 98.4 % after 20 cycles. The in-depth investigations conducted in this study will provide valuable insights into developing pH-responsive membranes to meet diverse demands, such as water rejection or oil rejection under complex conditions.

Impact of copper doping on optical, UV induced wettability and photo-catalytic properties of sol-gel synthesized ZnO thin films

Self-cleaning properties concerning with photo-catalytic activity of thin films are important to develop pollutant-free functional surfaces for various applications. In this work, enhanced self-cleaning properties (photo-catalytic properties) as well as UV induced wettability of ZnO thin films were achieved by the doping of copper through sol-gel spin coating method. X-ray diffraction pattern revealed c-axis and a-axis plane dominance for ZnO and Cu doped ZnO (CuZnO) films, respectively. Scanning electron microscopy images showed nano-grain surface for CuZnO films. Optical transmittance was found in the range 90–79%. Optical band gap values were estimated between 3.34 and 3.39 eV. CuZnO films were found to exhibit hydrophilic state having water contact angle (WCA) in the range of 35° to 57°. Irradiance with UV light produced super-hydrophilic state in all prepared films. Contact angle reduction rate was found best in case of 6% doped CuZnO thin film. The recovery time of contact angle was between 20 and 22 h for all the films. Photo-catalytic effect was evaluated with methylene blue (MB) and methyl orange (MO) dyes and better reduction rate of 38.4% and 40% respectively was attained with 6% Cu doped film. Moreover, MB & MO stain removal was observed.

0953 A Novel Active Humidifier for Non-Invasive Ventilated Patients

Abstract Introduction The RespirAq® humidifier is a novel, active heated humidifier that humidifies without the need for additional water. Within milliseconds, the humidifier switches between a super-hydrophilic state to capture moisture during expiration, and a super-hydrophobic state, returning moisture during inspiration. The device delivers gases at 37°C/100% relative humidity to individuals requiring humidification, including those with tracheostomies. We demonstrated the device meets EN ISO 80601 2 74:2020 during bench testing. This study aimed to compare the performance of the novel humidifier with a heated humidifier - HH (MR850™ Fisher & Paykel Healthcare) and a heat and moisture exchanger - HME (DAR™ Covidien) in healthy volunteers during non-invasive ventilation (NIV) using a non-vented full face mask. Methods Ten healthy volunteers were recruited. NIV was performed at different settings (inspiratory positive airway pressure (IPAP) range 5-20cmH20, expiratory positive airway pressure (EPAP) = 5cmH20) over a one-hour period. Humidity and temperature were collected continuously during the study. Results Sixty per cent of participants were female. Mean age of 35.6 ± 5.89 years (M±SD, n=10). Absolute humidity inside the face mask increased from 22.55 ± 2.41 mg/L without humidification to 30.18 ± 2.07 mg/L with an HME, and 39.09 ± 1.05 mg/L and 38.23 ± 1.78 mg/L when using a water-based heated humidifier and the novel humidifier, respectively. When comparing the performance of the humidification devices head-to-head, the two heated humidifiers significantly outperformed the HME (HME vs Novel = P < 0.0001, HME vs HH = p < 0.0001) and there was no significant difference seen between the two active humidifiers (p =0.2047). Conclusion Results show that the device meets the 12 mg/L absolute humidity established by the EN ISO 80601-2-74:2020 standards and that there is no significant difference in performance compared to traditional heated humidification. This suggests that the novel device can deliver the performance of a heater humidifier at the size, reliability and ease of use of a heat and moisture exchanger. Due to the mechanism of action, droplet/aerosol transmission of COVID-19 may also be mitigated. Further studies are warranted to confirm these findings. Support (if any) This research was supported by Tier 2 KiwiNet funding.