scholarly journals Transparent Self-Cleaning Coatings Based on Colorless Polyimide/Silica Sol Nanocomposite

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4100
Author(s):  
Yun-Je Choi ◽  
Ju-Hee Ko ◽  
Seung-Won Jin ◽  
Hyun-Soo An ◽  
Dam-Bi Kim ◽  
...  
Keyword(s):  
Particle Distribution ◽  
High Surface ◽  
Contact Angles ◽  
Silica Sol ◽  
Aprotic Solvents ◽  
Hydrophobic Contact ◽  
Polyamic Acid ◽  
Glass Substrates ◽  
Glass Slides ◽  
Self Cleaning

We herein report transparent self-cleaning coatings based on polyimide-fluorinated silica sol (PIFSS) nanocomposite. Polyamic acid-silica sol (PASS) suspensions were synthesized by adding four different amounts of a silica sol suspension to each end-capped polyamic acid solution. The PASS suspensions were spin-coated on glass slides, thermally imidized and treated with triethoxy-1H,1H,2H,2H-perfluorodecylsilane (TEFDS) to prepare PIFSS coatings. The PIFSS coatings showed high resistance to separation from glass substrates and thermal stability. Furthermore, the PIFSS coatings on the glass substrate could be cleanly removed using polar aprotic solvents and repeated coating was possible. As the amount of silica sol particles in the PIFSS coating was increased, the hydrophobic contact angle increased. Among them, PIFSS-10 and PIFSS-15 coatings showed nearly superhydrophobic contact angles (144° and 148°, respectively) and good self-cleaning property. It was confirmed by SEM and AFM studies that their hydrophobic and self-cleaning properties are due to uniform particle distribution and relatively high surface roughness. PIFSS-10 coating showed a high transmittance value (88%) at 550 nm and good self-cleaning property, therefore suitable as a transparent self-cleaning coating. The advantages of the coating are that the fabrication process is simple, and the substrate is reusable. The PIFSS coating is expected to be applied in solar cell panels, windows, lenses and safety goggles.

scholarly journals Magnetic Properties, Adhesion, and Nanomechanical Property of Co40Fe40W20 Films on Si (100) Substrate

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Wen-Jen Liu ◽  
Yung-Huang Chang ◽  
Sin-Liang Ou ◽  
Yuan-Tsung Chen ◽  
You-Cheng Liang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Surface Energy ◽  
Resonance Frequency ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
High Surface ◽  
Contact Angles ◽  
Thickness Effect ◽  
High Coercivity ◽  
High Surface Energy

In this study, a Co40Fe40W20 alloy was sputtered onto Si (100) with thicknesses (tf) ranging from 18 to 90 nm, and the corresponding structure, magnetic properties, adhesive characteristics, and nanomechanical properties were investigated. X-ray diffraction (XRD) patterns of the Co40Fe40W20 films demonstrated a significant crystalline body-centered cubic (BCC) CoFe (110) structure when the thickness was 42 nm, and an amorphous status was shown when the thickness was 18 nm, 30 nm, 60 nm, and 90 nm. The saturation magnetization (Ms) showed a saturated trend as tf was increased. Moreover, the coercivity (Hc) showed a minimum 1.65 Oe with 30 nm. Hc was smaller than 4.5 Oe owing to the small grain size distribution and amorphous structure, indicating that the Co40Fe40W20 film had soft magnetism. The low-frequency alternating current magnetic susceptibility (χac) decreased as the frequency was increased. The χac revealed a thickness effect when greater thicknesses had a large χac. The maximum χac and optimal resonance frequency (fres) of Co40Fe40W20 were investigated. The maximum χac indicated the spin sensitivity and was maximized at the optimal resonance frequency. The 90 mm thickness had the highest χac 0.18 value at an fres of 50 Hz. The contact angles of the Co40Fe40W20 films are less than 90°, which indicated that the film had a good wetting effect and hydrophilicity. The surface energy was correlated with the adhesion and displayed a concave-down trend. CoFeW films can be used as a seed or buffer layer; therefore, the surface energy and adhesion are very important. The highest surface energy was 30.12 mJ/mm2 at 42 nm and demonstrated high adhesion. High surface energy has corresponding strong adhesive performance. The increased surface roughness can induce domain wall pinning effect and high surface energy, causing a high coercivity and strong adhesion. The increase of hardness and Young’s modulus could be reasonably inferred from the thinner CoFeW films. The hardness and Young’s modulus of CoFeW films are also displayed to saturated tendency when increasing thickness.

Coated Hydrophilic Thin Film on Glasses Using Freeze Drying-Assisted Sol-Gel Technique for Self-Cleaning Building Materials

2010 ◽  
Vol 150-151 ◽  
pp. 1484-1487 ◽  
Author(s):  
Tao Lin ◽  
Xiang Chao Zhang
Keyword(s):  
Thin Film ◽  
Tio2 Film ◽  
Freeze Drying ◽  
Building Materials ◽  
Tio2 Thin Film ◽  
Sol Gel ◽  
Contact Angles ◽  
Ito Glass ◽  
Gel Technique ◽  
Self Cleaning

Titanium dioxide thin film has been successfully synthesized deposited on ITO glass substrates by the sol–gel dip-coating method using freeze drying technique. The precursor and TiO2 film were characterized using XRD, AFM and UV-vis absorption spectra analysis technologies. The XRD result demonstrates that the TiO2 film is well crystallized and consists of anatase phase only with (101) plane. The morphology of the nanoparticles of TiO2 thin film is spherical shape with grain size of 30.1 nm in average diameter and the surface of the TiO2 film is smooth. There is a strong wide UV absorption band around 387 nm and the calculated band gap (Eg) value of the TiO2 thin film is about 3.18 eV. The water contact angles for the thin film was only about 12°. The freeze drying-assisted sol-gel technique offers a novel process route in treating hydrophilic glasses for self-cleaning building materials and would be widely application for building energy saving.

Molecular Architecture and its role in Silica Sol-Gel Polymerization

1990 ◽  
Vol 180 ◽  
Author(s):  
P. C. Cagle ◽  
W. G. Klemperer ◽  
C. A. Simmons
Keyword(s):  
Molecular Level ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Silica Sol ◽  
Molecular Architecture ◽  
Model Studies ◽  
Large Size ◽  
Neutral Conditions ◽  
Very High

ABSTRACTSol-gel polymerization of [Si8O12](OCH3)8 in CH3CN under neutral conditions yields very high surface area (SBET > 900 m2/g) xerogels. This property is seen to result from the structure of the gel on the molecular level. According to N2 adsorption studies, model studies, and TEM studies, the large size and rigidity of the cubic [Si8O12] core structure leads to polymers whose rigidity inhibits extensive crosslinking of the type observed in orthosilicate derived xerogels.

Fabrication of ZnO Nanostructures with Self-Cleaning Functionality

2011 ◽  
Vol 364 ◽  
pp. 100-104 ◽  
Author(s):  
Kuan Ying Kok ◽  
Inn Khuan Ng ◽  
Nur Ubaidah Saidin ◽  
Farah Khuwailah Ahmad Bustamam
Keyword(s):  
Chemical Properties ◽  
Structural Features ◽  
Zno Films ◽  
Zno Nanostructures ◽  
Water Contact ◽  
One Dimensional ◽  
Glass Substrates ◽  
Electrochemically Deposited ◽  
Superhydrophobic Property ◽  
Self Cleaning

The science of biomimicry has served as a fusion point between nature and technology where one could adopt nature’s best solution for human’s use. Lotus leaf, for example, possesses self-cleaning capability due to the unique physical and chemical properties of its surface structural features. In this work, we aimed to mimic these features on glass surface using ZnO nanostructures to achieve the self-cleaning functionality. A series of ZnO films were electrochemically deposited on indium-doped tin oxide (ITO) conducting glass substrates from different aqueous electrolytes at systematically varied deposition potentials and electrolyte conditions. The surface morphology, density, orientation and aspect ratio of the ZnO micro/nanostructures obtained were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). ZnO ranging from two dimensional plate-like to one-dimensional needle-like micro/nanostructures were observed. Results from these studies show that lower electrolyte concentrations tend to favor one-dimensional growth of ZnO nanostructures that self-assembled into micron-size flower-like clusters at higher deposition temperatures. The ZnO-modified hierarchical dual-structured surface exhibits superhydrophobic property with water contact angle as high as 170o.

The Preparation of Silk Fibroin Modified PBT-co-PBS/PEG Composite Films and their Effects on Clinical Human Salivary Epithelial Cells Transplantation

2013 ◽  
Vol 18 ◽  
pp. 29-42
Author(s):  
Jie Zhu ◽  
Yue Ming Zhang ◽  
Zhi Cheng Tao ◽  
Nan Wei Xu ◽  
Li Qun Wang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Plasma Treatment ◽  
Silk Fibroin ◽  
High Surface ◽  
Composite Films ◽  
Contact Angles ◽  
Butylene Succinate ◽  
Poly Ethylene ◽  
Surface Modified ◽  
Salivary Epithelial Cells

We reported the preparation of surface modified poly(butylene terephthalate)-co-poly(butylene succinate)-b-poly(ethylene glycol) (i.e. PBT-co-PBS/PEG) films by three methods: silk fibroin coating, SO2 plasma treatment and silk fibroin anchoring. The obtained composite films were named SF/(PBT-co-PBS/PEG), SO2/(PBT-co-PBS/PEG) and SF/SO2/(PBT-co-PBS/PEG), respectively. Their surface properties were characterized by contact angles, surface energies and XPS. The biocompatibility of the films were further evaluated by the morphology, attachment, proliferation and viability of human salivary epithelial cells (HSG cells). Results revealed that SF/SO2/(PBT-co-PBS/PEG) possessed the high surface free energy (59.67 mJ/m2) and could immobilize a great amount of fibroin (SF surface coverage: 26.39 wt%), which attributed to the formation of such polar groups as hydrosulfide group, sulfonic group, carboxyl and carbonyl ones in the process of SO2 plasma treatment. The cell tests suggested that the silk fibroin anchoring could significantly enhance the biocompatibility of PBT-co-PBS/PEG, which implied the potential application of fibroin modified PBT-co-PBS/PEG for clinical HSG cells transplantation in artificial salivary gland constructs.

scholarly journals What factors affect lotus effect?

2018 ◽  
Vol 22 (4) ◽  
pp. 1737-1743 ◽  
Author(s):  
Chan-Juan Zhou ◽  
Dan Tian ◽  
Ji-Huan He
Keyword(s):  
Ionic Liquids ◽  
Surface Morphology ◽  
Size Effect ◽  
Contact Angles ◽  
Lotus Effect ◽  
Factors Affecting ◽  
Ph Values ◽  
Series Of Experiments ◽  
Main Factors ◽  
Self Cleaning

Lotus effect is the superhydrophobicity property, and widely used for self-cleaning in modern textile engineering. This paper reveals that the lotus effect is a kind of nanoeffect or size effect in nanotechnology, the surface morphology, solution?s molecule weight, and temperature are three main factors affecting the lotus effect. Solutions? pH values or ionic liquids are also discussed in this paper. A series of experiments are carried out to measure contact angles for different solutions/liquids on the lotus surface at different temperature.

Bistable Nature of the Hydrophobic Contact Angle on Rough Surfaces

2003 ◽  
Author(s):  
Bo He ◽  
Neelesh A. Patankar ◽  
Junghoon Lee
Keyword(s):  
Contact Angle ◽  
Theoretical Prediction ◽  
Rough Surface ◽  
Rough Surfaces ◽  
Contact Angles ◽  
Design Criterion ◽  
External Disturbances ◽  
Hydrophobic Contact ◽  
Energy States

This paper studies the bistable nature of the hydrophobic contact angle on the rough surfaces. It was experimentally shown that a droplet of liquid can liquid can form two different contact angles on a surface that has roughness patterns. External disturbances can cause a transition between the two different energy states. This paper verifies the theoretical prediction by matching experiments and establishes a design criterion for a robust hydrophobic rough surface on which the contact angle will not change due to external disturbances. This fact is critical in microfluidic applications, where a rough surface is used for applications based on wettability amplification.

scholarly journals Structural, optical and photocatalytic properties of erbium (Er3+) and yttrium (Y3+) doped TiO2 thin films with remarkable self-cleaning super-hydrophilic properties

RSC Advances ◽  
2020 ◽  
Vol 10 (29) ◽  
pp. 17247-17254
Author(s):  
Raquel da Silva Cardoso ◽  
Suélen Maria de Amorim ◽  
Gidiane Scaratti ◽  
Camilla Daniela Moura-Nickel ◽  
Rodrigo Peralta Muniz Moreira ◽  
...  
Keyword(s):  
Thin Films ◽  
The Self ◽  
Photocatalytic Properties ◽  
Tio2 Thin Films ◽  
Doped Tio2 ◽  
Glass Substrates ◽  
Self Cleaning

The self-cleaning and super hydrophilic properties of pristine TiO2 and of TiO2 doped with Er3+ or Y3+ transparent thin films deposited onto glass substrates were investigated.

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