Self-cleaning Surfaces Research Articles

In-situ design of hierarchical durable silica-based coatings on polypropylene films with superhydrophilic, superhydrophobic and self-cleaning properties

Superhydrophobic surfaces are receiving increasing attention due to their real-world applications. However, these surfaces suffer from a lack of durability and complicated synthetic processes. This research uses a combination of a simple in-situ coating process between oxygen-activated polypropylene films and unreacted silane monomers. The in-situ process uses a modified Stöber method with the addition of the surfactant cetyltrimethylammonium bromide (CTAB) which aggregates silica (SiO 2) particles in a basic aqueous solution. This resulted in a layer of covalently bonded hierarchical coating of individual and aggregated SiO 2 “flakes” and particles. These coatings were found to have at least double the surface roughness than samples prepared without CTAB with superhydrophilic properties due to their high surface roughness and hydrophilic surface chemical groups. A second layer of fluorocarbon silane monomers was reacted with the hydroxyl groups on the hierarchical SiO 2 coating resulting in films with excellent superhydrophobic and self-cleaning properties. The sample containing aggregated SiO 2 particle structures exhibited higher chemical and physical durability against external irritations including adhesion, different pH levels, detergent, abrasion and UV radiation by retaining high contact angles and low rolling angles. Samples coated with flake structures were negatively affected by mechanical irritations. This simple in-situ SiO 2 coating process in combination with different concentrations of CTAB has not been investigated and has promising potential for many practical applications such as superhydrophilic, superhydrophobic and self-cleaning surfaces.

Robust and UV-resistant multifunctional surface for self-cleaning, navigated oil absorption and oil/water separation

Traditional self-cleaning surfaces are always limited to defects of poor robustness, complex preparation process and single function. In order to address these problems, we have constructed a versatile self-cleaning superhydrophobic surface with reliable robustness, photodegradation, ease of manufacturing and magnetic navigation. This function integrated surface is conveniently fabricated by spraying a fluorosilane modified TiO2/Fe3O4 nanoparticles suspension onto an adhesive coated substrate, which was made by directly spraying the adhesive onto both soft and hard substrates to improve the robustness. During the volatilization of the ethanol-based suspension, due to the superior compatibility between the solvent and the adhesive, the functional nanoparticles are embedded in the adhesive layer and are firmly bound to it. This superhydrophobic surface shows significant robustness to damage tests and remain self-cleaning property even immersed in oil. By using this surface in oil-water separation, it indicates excellent separation efficiency for various oi-water mixtures. Meanwhile, the superhydrophobic surface shows excellent potential applications as a function integrated oil-water separation device contributed by the photodegradation property of TiO2 nanoparticles and magnetic navigation property from Fe3O4 nanoparticles.

Water dissociation at the water–rutile TiO2(110) interface from ab initio-based deep neural network simulations

The interaction of water with TiO2 surfaces is of crucial importance in various scientific fields and applications, from photocatalysis for hydrogen production and the photooxidation of organic pollutants to self-cleaning surfaces and bio-medical devices. In particular, the equilibrium fraction of water dissociation at the TiO2-water interface has a critical role in the surface chemistry of TiO2, but is difficult to determine both experimentally and computationally. Among TiO2 surfaces, rutile TiO2(110) is of special interest as the most abundant surface of TiO2's stable rutile phase. While surface-science studies have provided detailed information on the interaction of rutile TiO2(110) with gas-phase water, much less is known about the TiO2(110)-water interface, which is more relevant to many applications. In this work, we characterize the structure of the aqueous TiO2(110) interface using nanosecond timescale molecular dynamics simulations with abinitio-based deep neural network potentials that accurately describe water/TiO2(110) interactions over a wide range of water coverages. Simulations on TiO2(110) slab models of increasing thickness provide insight into the dynamic equilibrium between molecular and dissociated adsorbed water at the interface and allow us to obtain a reliable estimate of the equilibrium fraction of water dissociation. We find a dissociation fraction of 22 ± 6% with an associated average hydroxyl lifetime of 7.6 ± 1.8 ns. These quantities are both much larger than corresponding estimates for the aqueous anatase TiO2(101) interface, consistent with the higher water photooxidation activity that is observed for rutile relative to anatase.

Self-cleaning superhydrophobic fly ash geopolymer

Building materials with hydrophobic surfaces can exhibit increased service life by preventing moisture absorption or diffusion through their surfaces. For concrete used in construction, this hydrophobicity can prevent the corrosion of reinforcing steel bars. Geopolymers are a new cement-free binding material that have been extensively studied to replace Portland cement. However, similar to normal concrete, geopolymers are susceptible to the intake of moisture. This paper presents the fabrication of a superhydrophobic and self-cleaning surface on a fly ash geopolymer as a method to prevent moisture intake. A composite coating of polydimethylsiloxane (PDMS) solution containing dispersed polytetrafluoroethylene (PTFE) or calcium stearate (CS) microparticles was applied by dip-coating to form the hydrophobic surface. Additionally, fly ash was incorporated with the PTFE and CS microparticles to increase surface roughness and reduce material cost. The experimental results showed that the coating containing CS microparticles yielded a hydrophobic surface with a contact angle of 140°, while those containing PTFE microparticles provided a superhydrophobic surface with a contact angle of 159°. The incorporation of fly ash resulted in increased surface roughness, leading to a larger contact angle and a smaller sliding angle. A contact angle of 153° with a sliding angle of 8.7° was observed on the PTFE/fly ash-coated surface. The cleaning process was demonstrated with a test whereby dust was removed by water droplets rolling off the surface. The tested coating exhibited self-cleaning and waterproofing properties and could thus improve the sustainability of materials in building construction.

Bioinspired magnetism-responsive hybrid microstructures with dynamic switching toward liquid droplet rolling states.

The functionality of tunable liquid droplet adhesion is crucial for many applications such as self-cleaning surfaces and water collectors. However, it is still a challenge to achieve real-time and fast reversible switching between isotropic and anisotropic liquid droplet rolling states. Inspired by the surface topography on lotus leaves and rice leaves, herein we report a biomimetic hybrid surface with gradient magnetism-responsive micropillar/microplate arrays (GMRMA), featuring dynamic fast switching toward different droplet rolling states. The exceptional dynamic switching characteristics of GMRMA are visualized and attributed to the fast asymmetric deformation between the two different biomimetic microstructures under a magnetic field; they endow the rolling droplets with anisotropic interfacial resistance. Based on the exceptional morphology switching surface, we demonstrate the function of classification and screening of liquid droplets, and thus propose a new strategy for liquid mixing and potential microchemical reactions. It is expected that this intelligent GMRMA will be conducive to many engineering applications, such as microfluidic devices and microchemical reactors.

Topographic de-adhesion in the viscoelastic limit.

The superiority of many natural surfaces at resisting soft, sticky biofoulants have inspired the integration of dynamic topography with mechanical instability to promote self-cleaning artificial surfaces. The physics behind this novel mechanism is currently limited to elastic biofoulants where surface energy, bending stiffness and topographical wavelength are key factors. However, the viscoelastic nature of many biofoulants causes a complex interplay between these factors with time-dependent characteristics such as material softening and loading rate. Here, we enrich the current elastic theory of topographic de-adhesion using analytical and finite-element models to elucidate the nonlinear, time-dependent interaction of three physical, dimensionless parameters: biofoulant's stiffness reduction, the product of relaxation time and loading rate, and the critical strain for short-term elastic de-adhesion. Theoretical predictions, in good agreement with numerical simulations, provide insight into tuning these control parameters to optimize surface renewal via topographic de-adhesion in the viscoelastic regime.

Cu-doped SnO2 nanoparticles: size and antibacterial activity investigations.

Nowadays, the use of self-cleaning surfaces is increasing globally, especially after the COVID-2019 pandemic, and the use of nanoparticles has been shown as a plausible option for this purpose. In the present study, Cu-doped SnO2 nanocrystals were successfully synthesized (in the copper content range of 0-30 mol%) using the polymeric precursor method. The structural, morphological, vibrational, and antibacterial activity were carefully studied to unveil the effect of copper ions on the properties of the hosting matrix, aiming at maximizing the usage of Cu-doped SnO2 nanocrystals. The results show fabrication of nanoparticles near their respective exciton Bohr diameter (5.4 nm for SnO2), however, monophasic SnO2 was observed up to 15 mol%. Above this limit, a secondary CuO phase was observed, as shown by the assessed X-ray diffraction (XRD), Fourier transform infrared, and Raman spectroscopy data. Furthermore, the redshift of the primary A1g vibrational mode of SnO2 is successfully described using the phonon-confinement model, demonstrating a good relationship between the Raman correlation length (L) and the crystallite size (〈D〉), the latter determined from XRD. Regarding the antibacterial activity, assessed via the disc-diffusion testing method (DDTM) while challenging two bacterial species (S. aureus and E. coli), our results suggest a rapid diffusion of the nanoparticles out of the paper disc, with a synergistic effect credited to the Sn1-xCuxO2-CuO phases contributing to the inhibition of the bacteria growth. Moreover, the DDTM data scales with cell viability, the latter analyzed using the Hill equation, from which both lethal dose 50 (LD50) and benchmark dose (BMD) were extracted.

A one step self-cleaning surface with robust superhydrophobic and photocatalytic properties: Electrostatic sprayed fluorinated ethylene propylene mixed with nano TiO2–SiO2 particles

In this research, a one-step and environmentally friendly method, free from the complexity of chemical techniques, was utilized to prepare a superhydrophobic surface that can be implemented on large scale. To this end, at first, silica nanoparticles were made hydrophobic through the silanization method, then got mixed with titanium dioxide nanoparticles and fluorinated ethylene propylene (FEP). Afterward, the combined materials were deposited on aluminum substrate using an electrostatic spraying method. In order to assess the fabricated surface, scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and contact angle measurement are accomplished. In addition, the photocatalytic activity by the degradation of oleic acid and methylene blue (MB) upon UV exposure was studied. Results indicated formation of a superhydrophobic photocatalyst with contact angle over 150 ° . This superhydrophobic surface containing nano silica content 12 wt.% and TiO 2 20 wt.% exhibited excellent photocatalytic activities in the organic materials degradation. The obtained photocatalyst surfaces also revealed proper stability in acidic (pH = 5) and alkaline (pH = 11) media. Moreover, a suitable stability was observed in the fouling medium with duration 10 h while no change in the static contact angle occurred.

ИННОВАЦИОННЫЕ ТЕХНОЛОГИИ В СТРОИТЕЛЬСТВЕ

The article characterizes the importance of innovative technologies in modern construction, their advantages, such as improving construction processes, increasing the efficiency of resource use and reducing costs. The author highlights the problems of modern construction associated with the need to use innovative technologies. The application of nanotechnologies to improve the properties of materials and create self-cleaning surfaces and increase thermal insulation is disclosed. The examples presented in the article demonstrate the potential benefits of using nanotechnology in construction, including the improvement of the properties of materials and structures, as well as the creation of self-repairing materials, which highlights the active development of science in the field of nanotechnology around the world. The concept of seamless construction, based on the use of digital technologies, innovative materials and flexible project management methods, allows you to achieve a more efficient and environmentally friendly construction process, reduce material and energy costs, reduce construction time and the amount of waste generated during the construction process, as well as improve the quality and stability of structures. In construction, the use of robotic technologies is a current trend that allows using robots and automated systems to improve the accuracy and quality of work, reduce time and errors, as well as reduce labor costs and increase labor safety. The above facts indicate that the use of virtual and augmented reality in design and construction is an innovative technology that allows you to optimize the planning process, increase accuracy and reduce errors, as well as improve coordination of work and reduce construction time.

The isotropic and anisotropic self-cleaning surfaces by using only femtosecond laser

The current study describes a technique for surface modification that uses only femtosecond laser pulses that are extremely brief. The development in this research is the feature with periodically and directionally fabricated hierarchical micrometre scaled shapes with nanometer scaled structures. Although the developed features have complex structural makeup, they exhibit isotropic and anisotropic behaviour in superhydrophobicity. The developed Stainless Steel AISI 304 surface with appropriate modification using a femtosecond laser is the used method in this study. The recommended method may be applied to other vulnerable surfaces, including ceramic, polymers, semiconductors, and insulators as well as metals and alloys. The few functional fields that may use this method include self-cleaning surfaces, antibacterial surfaces, anticorrosion surfaces, anti-icing surfaces, and anti-biofouling surfaces. The Opto digital microscope with nanoscale resolution profoundly assisted us in finding developed features in its accuracy. We studied all of the featured topographies using sophisticated imaging tools. The presence of the preplanned features can also be demonstrated by field emission and tungsten filament scanning electron microscopy, and by atomic force microscopy. Studies on hydrophobicity carried out with Matlab assistance included a digital goniometer. Surfaces that are isotropic and directional with hydrophobic behaviour differed by water rolling on 0.5–3.5° tilted angles. All the manufactured superhydrophobic surfaces are reported to be above 155° and at most 167.13° is also a notable value. The results of the conical microspikes, which mimic a lotus leaf, show that they are exclusively hydrophobic isotropic at 0.5° of sliding angle. Biomimetic sinusoidal microgrooves in grass leaves reported remarkably directional or anisotropic hydrophobicity at a 2.5° rolling angle. So that we can elaborate on the use of femtosecond laser on hydrophobicity, we are reporting the results that have been proven to the appropriate fields. The ultrashort pulsed micromachining is used as the low waste machining technique's least time-consuming operation.

Влияние титаносиликатных порошков на прочностные свойства бетонных смесей и их способность к самоочищению

The effect of titanosilicate additive on the strength and self-cleaning properties of concrete mixes was studied.It was revealed that the titanosilicate additive helps to increase the strength of fine-grained concrete. The maximum increase in strength is observed when the content of the additive in the amount of 1 wt. %. There is a complete degradation of the organic dye on the surface of the concrete under the influence of both UV and visible light. The use of titanosilicate additive in the composition of the concrete mix will make it possible to obtain fine-grained concrete with increased strength and a self-cleaning surface.

Fabrication of vanadium dioxide thin films and application of its thermochromic and photochromic nature in self-cleaning: A review

Vanadium dioxide (VO2) and many binary compounds of vanadium can transform from a semiconducting state to a metallic state under the influence of temperature or light. The transformation is triggered by modifications in the oxide's crystalline structure, often initiated by changes in its light-sensing and electrical attributes. This ability makes them suitable for smart coatings, electronic switches, self-cleaning surfaces, window glass, and many more. These potential applications have prompted tremendous interest in VO2thin films, focusing on their fabrication and application. This article reviews current fabrication methods for VO2thin films, the potential application of their thermochromic and photochromic properties in self-cleaning coatings, the challenges facing their application, and some remedies devised to address the challenges. The various challenges facing its different synthesis and fabrication methods are also highlighted. First, the different transitional phases of VO2and routes to transform from one stage to the other are presented.

Facile fabrication of superhydrophobic porous materials using the water-based aza-Michael reaction for high-efficiency oil-water separation

Superhydrophobic porous materials are widely used in oil-water separation due to their water-blocking and oil-passing properties. However, the preparation of most superhydrophobic porous materials is generally energy-intensive and must be performed using organic solvents. In this study, we describe a straightforward and cost-effective strategy for fabricating superhydrophobic coatings on nanosized soil particle-modified stainless steel mesh (SSM). The coating is prepared via the aza-Michael reaction of stearyl acrylate and melamine-urea–formaldehyde (MUF) resin catalysed by methyl cyclodextrin in water. Superhydrophobic meshes with water contact angles (WCAs) exceeding 150° are obtained, exhibiting extraordinary water repellency. The superhydrophobic mesh also effectively prevents surface contamination, creating a self-cleaning surface that is both waterproof and dustproof. Most importantly, the superhydrophobic mesh presents excellent oil separation performance for oil-water mixtures of various compositions, maintaining extremely high separation efficiency (>98%) even after 80 cycles. Additionally, we successfully apply this strategy to the preparation of superhydrophobic melamine sponges with excellent oil adsorption capacity (17.6–44.2 g/g). This innovative study provides an effective strategy for designing biomimetic superhydrophobic surfaces and is a promising development in the field of environmentally friendly oil-water separators.

A brief overview of the marine environmentally friendly anti-fouling surface strategy

Fouling that develops on the surface of maritime environmental components, such as hulls and pipelines, can lead to various adverse effects and large losses to the company. Living organisms such as bacteria, algae, and shellfish, as well as organic and inorganic materials, settle on the surface and can affect function and productivity. The development of anti-fouling surfaces, such as surfaces containing chemicals that are biocidal agents, has long been used. However, the usage has been banned because of marine environmental effects. In this review, the current state of strategy for the fabrication of an environmentally anti-fouling surface that is suitable for marine environments is discussed. Several strategies for producing environmentally friendly anti-fouling surfaces have been established, such as the development of surfaces with antibacterial and self-cleaning properties, and have been successfully implemented in other fields such as textiles, medicine, and buildings. Among the methods that may be used are the development of surfaces that include biocides; surfaces that inhibit and prevent bacterial adhesion; and surfaces that have components that can kill bacteria when contacted. Self-cleaning surfaces, on the other hand, can be made by creating surfaces with superhydrophobic or superhydrifilic wettability properties, as well as photocatalytic surfaces with self-cleaning properties that can be used in the marine environment.

Fabrication of Superhydrophobic Surfaces Using Inverted Glancing Angle Deposition (I-GLAD)

Abstract This paper presents a novel approach for fabricating superhydrophobic surfaces using inverted glancing angle deposition (I-GLAD). GLAD is an advanced physical vapor deposition technique that utilizes substrate tilt and rotation to create three-dimensional nanofeature arrays. Unlike conventional top-down nanofabrication methods, GLAD offers unique advantages in generating various nanofeatures such as pillars, springs, chevrons, ribbons, and nanoporous membranes. Superhydrophobicity, inspired by natural examples like lotus leaves and cicada wings, relies on highly porous micro/nanostructures that reduce surface energy and impart water-repellent properties. GLAD’s capability to produce hierarchical and porous nanostructures makes it an ideal candidate for superhydrophobic surface fabrication. Previous researches have proposed GLAD processes for superhydrophobic surfaces; however, these approaches suffer from flaws such as being time-consuming or requiring challenging template assistance. In this paper, we introduce a new I-GLAD approach for creating superhydrophobic surfaces that eliminates the need for a seeding layer and an additional coating, simplifying the fabrication process. The fabrication process of I-GLAD includes natural seeding, growing, capping, and inverting. The resulting superhydrophobic surfaces exhibit a high water contact angle of over 155 deg. We further explore additional GLAD recipes to create surfaces with different water contact angles, enabling a comprehensive analysis of superhydrophobic properties. Potential applications for superhydrophobic surfaces include anti-icing coatings, self-cleaning surfaces, and antimicrobial surfaces.

Luminescence, Paramagnetic, and Electrochemical Properties of Copper Oxides-Decorated TiO2/Graphene Oxide Nanocomposites

The properties of newly synthesized Cu2O/CuO-decorated TiO2/graphene oxide (GO) nanocomposites (NC) were analyzed aiming to obtain insight into their photocatalytic behavior and their various applications, including water remediation, self-cleaning surfaces, antibacterial materials, and electrochemical sensors. The physico-chemical methods of research were photoluminescence (PL), electron paramagnetic resonance (EPR) spectroscopy, cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The solid samples evidenced an EPR signal that can be attributed to the oxygen-vacancy defects and copper ions in correlation with PL results. Free radicals generated before and after UV-Vis irradiation of powders and aqueous dispersions of Cu2O/CuO-decorated TiO2/GO nanocomposites were studied by EPR spectroscopy using two spin traps, DMPO (5,5-dimethyl-1-pyrroline-N-oxide) and CPH (1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine), to highlight the formation of hydroxyl and superoxide reactive oxygen species, respectively. The electrochemical characterization of the NC modified carbon-paste electrodes (CPE) was carried out by CV and DPV. As such, modified carbon-paste electrodes were prepared by mixing carbon paste with copper oxides-decorated TiO2/GO nanocomposites. We have shown that GO reduces the recombination process in TiO2 by immediate electron transfer from excited TiO2 to GO sheets. The results suggest that differences in the PL, respectively, EPR data and electrochemical behavior, are due to the different copper oxides and GO content, presenting new perspectives of materials functionalization.

Recent advances in responsive membrane functionalization approaches and applications

ABSTRACT In recent years, significant advances have been made in the field of functionalized membranes. With the functionalization using various materials, such as polymers and enzymes, membranes can exhibit property changes in response to an environmental stimulation, such as heat, light, ionic strength, or pH. The resulting responsive nature allows for an increased breadth of membrane uses, due to the developed functionalization properties, such as smart-gating filtration for size-selective water contaminant removal, self-cleaning antifouling surfaces, increased scalability options, and highly sensitive molecular detection. In this review, new advances in both fabrication and applications of functionalized membranes are reported and summarized, including temperature-responsive, pH-responsive, light-responsive, enzyme-functionalized, and two-dimensional material-functionalized membranes. Specific emphasis was given to the most recent technological improvements, current limitations, advances in characterization techniques, and future directions for the field of functionalized membranes.

Development of modern nanotecnologies and combined biotoxicity problems

Fast progress in modern nanotechnologies based on use of nanoparticles, nanofibers and nanotubes with different composition, shape and size allows elaboration of materials with superhigh strength, thermal and electric conductivity, acoustical and optical properties. Those materials are already widely used in industry, transportation, aerospace, marine and civil engineering, food processing and medicine. Some examples of nanoreinforces composites, superhydrophobic self-cleaning surfaces, nanodyes and suspensions of nanoparticles are described. The problem of uncontrolled accumulation of some types of nanoparticles in our cells and tissues is discussed within the concept of nanotoxicity. Since the history of permanent observation of human health in connection with nanodust accumulation in the atmosphere, waters and soils is not enough long, the detailed evidences must be documented, systematized and discussed.
 In this study a brief systematic review of literature on the biotoxicity problems caused by modern nanotechnologies is given. Production of the nanoparticles, nanofibers and nanotubes for industry, transportation, food processing, as well as utilization of the used materials which properties were modified by the nanotechnologies leads to permanent rise of the nanodust in the atmosphere, soils, river waters, lakes and the sea bottom. Their uncontrolled interaction with flora and fauna could be catastrophic for human health and life on the Earth. Promising ways for the problem solution and perspectives are discussed. Some own results on the protective action of nanodiamonds, silver and some other nanoparticles are presented. A vital necessity of an open access database on known types of nanoparticles, their use in the materials and documented influence of health of animals and humans is discussed

Biosynthesized metallic nanocatalysts in the removal and degradation of pollutants

• Biogenic synthesis of nanocatalysts is facile, up-scalable, inexpensive, and eco-friendly. • Biosynthesized metallic nanocatalysts (BMNs) are widely explored for environmental applications. • BMNs advantages: High catalytic activity, chemical reactivity, selectivity, and recyclability. • BMNs can efficiently convert industrial wastes into the high-value materials. • BMNs should be further optimized and analytically evaluated for large-scale production. Metallic nanocatalysts have been widely synthesized and deployed for assorted applications, including water splitting, degradation of pollutants, CO 2 reduction, self-cleaning surfaces, hydrogen evolution, etc. Biosynthesis of such nanocatalysts encompasses crucial benefits of simplicity, up-scalability, inexpensiveness, and eco-friendliness, and has been widely explored for the removal and degradation of pollutants. Biosynthesized metallic nanocatalysts not only exhibit appropriate stability and reusability, but also offer excellent catalytic activity while using much lower resources and energy. Herein, the recent advancements related to the biosynthesis of metallic nanoparticles with respect to their catalytic applications for the removal/catalytic degradation of various pollutants are deliberated, focusing on important challenges and future perspectives, while most of the published research has predominantly focused on the synthesis approaches and its mechanism.

Multifunctional bandgap-reduced ZnO nanocrystals for photocatalysis, self-cleaning, and antibacterial glass surfaces

A set of ZnO nanocrystals assembly with tuneable reduced bandgaps was prepared via thermal decomposition of ZnO2 precursor. A detailed Raman and EPR analysis revealed ZnO rich in oxygen vacancies with concentration varying upon annealing temperature. The structural defect features corroborated with the bandgap variations indicate photocatalytic response in the visible-light, which was evaluated by using monochromatic LEDs (377, 401, and 429 nm wavelengths) for a correct assessment of the photocatalytic activities of samples in the close vicinities of their bandgaps. It was revealed, that bandgap reduced ZnO exhibits only little yet negligible photocatalytic activity towards Methylene Blue discoloration under 429 nm diode. The Photocatalytic experiments using scavengers support the model that oxygen vacancies easily trap photo-excited electrons (whether VO+ and VO++ state) and, if the energy level of this donor state is close enough, the trapped electron could easily thermalize to the conduction band as well as recombine with photo-excited holes. Furthermore, oxygen vacancies rich ZnO nanocrystals treated glasses were prepared and their photocatalytic-induced self-cleaning property, wettability, and antibacterial activities were evaluated under both UV and visible-light. Besides excellent antibacterial activities against both S. aureus and E. coli, which was achieved even in dark, both photocatalytically-induced self-cleaning ability and wettability provided yet another indirect evidence of the inability of bandgap-reduced ZnO to become activated under visible-light irradiation.