Search results

This paper introduced the simple synthesis process of self-cleaning coating with fog-resistance property using hydrophobic polydimethylsiloxane (PDMS) polymer and nano-calcium carbonate (nano-CaCO₃) and titanium dioxide (TiO₂).

The synthesis method of PDMS/nano-CaCO₃-TiO₂ is based on sol-gel process. The crosslinking between PDMS and nanoparticles is driven by the covalent bond at temperature of 50°C. The 3-Aminopropyltriethoxysilane is used as binder for nanoparticles attachment in polymer matrix. Two fabrication methods are used, which are dip- and spray-coating methods.

The prepared coated glass fulfilled the requirement of standard self-cleaning and fog-resistance performance. For the self-cleaning test BS EN 1096-5:2016, the coated glasses exhibited the dust haze value around 20%–25% at tilt angle of 10°. For the antifog test, the coated glasses showed the fog haze value were below 2% and the gloss value were above 85%. The obtained results completely achieved the standard antifog value ASTM F659-06 protocol.

Findings will provide an infrastructure support for the building glass to enhance building’s energy efficiency, cleaning performance and friendly environment.

This study proposed the simple synthesis method using hydrophobic polymer and nano-CaCO₃ and nano-TiO₂, which can achieve optimum self-cleaning property at low tilt angle and fog-resistance performance for building glass.

The research findings have high potential for building company, cleaning building company and government sector. The proposed project capable to reduces the energy consumption about 20% per annum due to labor cost, time-consuming and safety during manual cleaning.

The novel method to develop self-cleaning coating with fog-resistance using simple synthesis process and fabrication method for building glass application.

This paper aims to design the nano-titanium dioxide (TiO₂) coating system which has superhydrophilic property, self-cleaning mechanism and antifog property as well as strong adhesion on glass substrate.

Two hydrophilic materials have been used such as TiO₂ nanoparticles as fillers and hydrophilic copolymer, Pluronic F-127 by using simple sol–gel approach. The prepared solution was applied onto glass through dip- and spray-coating techniques and then left for drying at ambient temperature.

The nano-TiO₂ superhydrophilic coating has achieved the water contact angle of 4.9° ± 0.5°. The superhydrophilic coating showed great self-cleaning effect against concentrated syrup and methylene blue where thin layer of water washes the dirt contaminants away. The nano-TiO₂ coating exhibits great antifog performance that maintains high transparency of around 89% when the coated glass is placed above hot-fog vapor for 10 min. The fog droplets were condensed into water film which allowed the transmission of light through the glass. The strong adhesion of coated glass shows no total failure at scratch profile when impacted with scratch load of 500, 800 and 1,200 mN.

Findings will be useful in the development of self-cleaning superhydrophilic coating that is applicable on building glass and photovoltaic panel.

The developed nano-TiO₂ coating is developed by the combination of hydrophilic organic copolymer–inorganic TiO₂ network to achieve great superhydrophilic property, optimum self-cleaning ability and supreme antifog performance.

The findings will be useful for residents in building glass window where the application will reduce dust accumulation and keep the glass clean for longer period.

The synthesis of nano-TiO₂ superhydrophilic coating which can be sprayed on large glass panel and cured at ambient temperature.

The paper aims to investigate the effect of Degussa P-25 Titanium Dioxide (TiO₂) nanoparticles on hydrophobicity and self-cleaning ability as a single organic coating on glass substrate.

Two methods have been used to enhance the hydrophobicity on glass substrates, namely, surface modification by using low surface energy isooctyltrimethoxysilane (ITMS) solution and construction of rough surface morphology using Degussa P-25 TiO₂ nanoparticles with simple bottom-up approach. The prepared sol was applied onto glass substrate using dip-coating technique and stoved in the vacuum furnace 350°C.

The ITMS coating with nano TiO₂ pigment has modified the glass substrate surface by achieving the water contact angle as high as 169° ± 2° and low sliding angle of 0° with simple and low-cost operation. The solid and air phase interface has created excellent anti-dirt and self-cleaning properties against dilute ketchup solution, mud and silicon powder.

Findings will be useful in the development of self-cleaning and anti-dirt coating for photovoltaic panels.

Sol method provides the suitable medium for the combination of organic–inorganic network to achieve high superhydrophobicity and optimum self-cleaning ability.

Application of blended organic–inorganic sol as self-cleaning and anti-dirt coating film.

Nanostructured titanium dioxide (TiO₂) coatings can potentially address the current surge in façade cleaning cost, maintenance and labour problems. The purpose of this paper is to investigate potential maintainability issues and design challenges concerning the effective performance of TiO₂ façade coatings’ hydrophilic properties, especially in tropical environments such as Singapore. This paper aims to establish a list of green maintainability design criteria to help minimise future TiO₂ façade coating issues when this coating is applied on commercial buildings with concrete and stonemasonry façade materials.

A mixed-mode approach that includes a literature review, site investigation, instrumental case studies and expert interviews is used in this study.

TiO₂ coatings help improve façade performance whilst offering environmental benefits to society. This study reports that green maintainability design criteria are vital requirements in designing sustainable buildings at the outset. The identified defects and issues will aid in ensuring the effectiveness of TiO₂ application in building façades.

This study acts as a foundation for future researchers to strengthen this little researched area, serves as a useful guide in preventing possible TiO₂ coating issues and promotes industry awareness of the use of TiO₂ façade coatings.

The self-cleaning properties of nanostructured titanium dioxide facade coatings are useful in Singapore's tropical climate. However, its potential maintenance issues need to be determined right at the design stage. The purpose of this paper is to highlight the development of the design for maintainability tool which is a multicriteria design decision score sheet that evaluates the maintainability potential of nano-facade coating applications on high-rise façades with concrete and stonemasonry finishes and curtain walls.

Quantitative methods (expert and practitioner surveys) are conducted in this research study. Analytic hierarchy process (AHP) and sensitivity analysis were used to develop a robust Design for Maintainability tool.

Safety measures indicator received the highest weighted score by experts, while the maximizing performance, minimizing risk, minimizing negative environmental impact and minimizing consumption of matter and energy were the top ranking main criteria by both experts and practitioners. The top ranked design for maintainability sub-criteria identified by practitioners and experts were risk management, maintenance considerations, climatic conditions, safety measures, lifecycle cost and maintenance access, sun's path, rainfall intensity, biological growth measures and building age profile.

Most researches on the maintainability of nano-façade coatings uses experimentation to test the durability of nano-façade coatings, while this study focuses on design based empirical data such as establishing and ranking the list of design for maintainability criteria or indicators to minimize future defects and maintenance issues. The design for maintainability tool contributes to the maintainability of nano-façade coatings leading to maximizing its performance while minimizing cost, risks, resource consumption and negative environmental impact.

The purpose of this study is to evaluate the possibility of using titanium dioxide coating in the field of architectural heritage.

In this research, a titanium dioxide coating was prepared and then applied to the travertine stone surfaces. The nature of the coating was determined through various observations and analyses. Moreover, the effect of photocatalytic self-cleaning was evaluated using an organic dye (Rhodamine B).

The results of XRD, DLS and SEM confirmed the formation of small anatase crystals. The hydrophilic behavior on the surface was observed by coatings based on titanium dioxide.

The self-cleaning ability of titanium dioxide is due to the synergistic effect of its optical inductive property, which is activated with sunlight.

The self-cleaning coatings are interested for many industries. The reported data can be used by the formulators working in the research and development departments.

Self-cleaning systems are considered as smart coatings. Therefore, the developing of its knowledge can help to extend its usage to different applications.

The application of titanium dioxide coating in the field of architectural heritage is a great challenge. Therefore, in this research, a titanium dioxide coating was prepared by sol-gel method and then applied on travertine surfaces and its properties were studied.

This paper aims to study the Improvements in self-cleaning property of the white acrylic water-based paint by addition of different percentages of three commercially available titanium dioxide (TiO₂) nanoparticles as additives. Then, due to the risk of destruction of polymeric materials in the presence of nanoparticles, degradation of dry paint film samples was investigated for 15 days using two important chalking and yellowing factors. Finally, the TiO₂-modified paint sample with the best performance and optimum percentage of TiO₂ nanoparticles that produced desired self-cleaning and dry film properties was introduced.

Self-cleaning and dry film properties of white acrylic water-based paint were investigated by addition of three various types of commercial available TiO₂ nanoparticles (SSP-25, STA-100 and KA-100). X-ray diffraction, transmission electron microscopy and Brunauer–Emmett–Teller were used for characterization of TiO₂ samples. Colorimetric tests in decolourization of C.I. Basic Red 46 (BR46) were used for determination of self-cleaning properties of TiO₂-modified paints in comparison with unmodified paint sample. Also, paints defects such as chalking and yellowing were tested along two weeks.

The results indicated that, in all types of TiO₂ nanoparticles, by increasing the amount of TiO₂ in modified paint, self-cleaning property of the samples was enhanced. The paint containing SSP-25 indicated better self-cleaning properties than others due to its larger surface area. However, its usage above 3.5 weight per cent caused yellowing and chalking defects in dried paint film.

In this research, TiO₂-modified paint sample with the best performance in both self-cleaning and mechanical properties was selected among the nine sets of prepared paint samples. All the materials used in this research such as acrylic resin and three types of TiO₂ nanoparticles are of industrial grade. Therefore, the introduced TiO₂-modified paint sample has the potential for the commercial production as a building exterior paint.

In the present study, an attempt at introducing a self-cleaning paint sample with acceptable mechanical properties using three types of commercially available TiO₂ nanoparticles as additives and industrial grade of acrylic resin which is the most commonly used water-based resin in building paints, as binder. As far as it was searched in the literatures, the parallel study of the self-cleaning and mechanical properties of paints has not been reported as noteworthy. Self-cleaning property of the acrylic water-based paint samples was investigated by adding three types of the commercially available TiO₂ nanoparticles. Also considering the possible detrimental effects of TiO₂ nanoparticles on polymeric materials and consequently on physical properties of the paint, chalking and yellowing factors in dried paint samples were evaluated.

Self-cleaning fabrics have aroused attention in recent years by showing great potential in changing our life style to a more environmental friendly way. Although efforts have been devolved to boost the efficiency of photocatalytic self-cleaning functions, there have been limited studies with regard to the effect of the self-cleaning finishing on fabric properties. One of the criteria in determining the usability of a fabric is its mechanical properties. In order to enhance the practicability of the self-cleaning coating treatment and widen its application, the effect of a titanium dioxide photocatalytic coating on the low-stress mechanical properties of the fabrics is studied.

This study aims to describe the design and synthesis of two novel azo and imine chromophores-based dyes derived from two different aldehydes with intramolecular colour matching that are pH sensitive.

The visible absorption wavelength (λ_max) was extended when azo chromophore was included in imine-based systems. The dyed patterns created sophisticated colour-changing paper packaging sensors with pH-sensitive chromophores using alum as a mediator or mordant. Due to the tight adhesive bonding, the dyes on paper’s cellulose fibres could not be removed by ordinary water even at extremely high or low pH, which was confirmed by scanning electron microscopy analysis. The dyed patterns demonstrated an evident, sensitive and fast colour-changing mechanism with varying pH, from pale yellow to red for Dye-I and from pale yellow to brown-violet for Dye-II.

The λ_max for colour changing was recorded from 400 to 490 nm for Dye-I, whereas from 400 to 520 for Dye-II. The freshness judgement of food was checked using actual experiments with cooked crab spoilage, where the cooked crab was incubated at 37 ^oC for 6 h to see the noticeable colour change from yellow to brown-violet with Dye-II. The colour-changing mechanism was studied with Fourier transform infrared (FTIR) spectra at different pH, and thin layer chromatography, nuclear magnetic resonance and FTIR spectroscopy studied the desired structure formation of the dyes. Potential uses for smart packaging sensors include quickly detecting food freshness during transportation or right before consumption.

1. Two novel azo-imine dyes have been synthesized with a pH-responsive effect. 2. The pH-responsive mechanism was studied. 3. The study was supported by computational chemistry using density functional theory. 4. The obtained dyes were used to make pH-responsive sensors for seafood packaging to judge the freshness.