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Hydrophobic and Hydrophilic Polymer Coatings
Published in Sanjay Mavinkere Rangappa, Jyotishkumar Parameswaranpillai, Suchart Siengchin, Polymer Coatings, 2020
Sanjay Remanan, Harikrishnan Pulikkalparambil, Sanjay Mavinkere Rangappa, Suchart Siengchin, Jyotishkumar Parameswaranpillai, Narayan Chandra Das
The dip coating method comprises of simple immersion and withdrawal steps. In this method, the substrate is immersed into the coating medium and, after a specified time, withdrawn from the medium at a predefined speed and the coated substrate is allowed to dry. It is a low-cost process in which the thickness can be easily adjusted. Coating medium, coating speed, viscosity, lift-off angle, surface tension, gravitational force, dwell time, and viscous drag can significantly affect the quality of the dip coating process. This process is widely used for the modification of fibers and objects with intricate structures, where a high production output is generally needed to regulate the uniform composition of the liquid mixture after a specified time (Gutoff and Cohen 2010; ten Elshof 2015; Wypych 2016).
Printing and Recent Developments
Published in Asis Patnaik, Sweta Patnaik, Fibres to Smart Textiles, 2019
Rasiah Ladchumananandasivam, Iris Oliveira Da Silva, Luciani Paola Rocha Cruz Barros, Elisângela Bezerra das Neves Holanda
Dip coating is a technique used to apply layers or films (usually polymeric) on the materials (Oliveira and Zarbin 2005; Nassar et al. 2003). In this process, the substrate to be coated is submerged perpendicularly within the solution containing the material of interest and then withdrawn at a well-defined rate under controlled temperature. The insertion and removal of the substrate in the solution must be performed in a constant manner and without any type of vibration or external interference, in order to guarantee the homogeneous deposition of the material of interest. The residence time of the substrate in the solution before its removal is also an important control factor. This means that in order to obtain quality layers, in addition to the characteristics of the substrate and the precursor solution (solvent, concentration, viscosity, type of precursor), it is necessary to use equipment that promotes the insertion and removal of the substrate with high stability, with fine speed control and free from vibration (Oliveira and Zarbin 2005). The thickness of the coating is mainly defined by the withdrawal rate, the solid content and the viscosity of the liquid.
Sensor Systems for Label-Free Detection of Biomolecular Interactions: Quartz Crystal Microbalance (QCM) and Surface Plasmon Resonance (SPR)
Published in Yallup Kevin, Basiricò Laura, Iniewski Kris, Sensors for Diagnostics and Monitoring, 2018
Şükran Şeker, M. Taner Vurat, Arin Doğan, A. Eser Elçin, Y. Murat Elçin
The dip coating process is an easier and low-budget way to prepare nanometer-thick films on quartz surfaces. It is based on the adsorption of the polymer on the surface from the polymer solution with suitable concentration. Briefly, the quartz crystal is dipped into a diluted polymer solution for a duration. Then, the excess solution is carefully removed from the crystal’s surface with filter paper from the edge of the crystal. Finally, the crystal is kept under dry conditions (e.g., in air). The disadvantage of the process is that the thickness differs between the edges and the center of the coated layer due to the evaporation effect. The main dip coating parameters are the concentration, the dipping time, the withdrawal velocity, and the viscosity of the solution, which play key roles in preparing the film with the desired thickness and surface morphology for various applications [21].
A critical overview of thin films coating technologies for energy applications
Published in Cogent Engineering, 2023
Mohammad Istiaque Hossain, Said Mansour
The dip-coating process is shown in Figure 13. As studied previously (Du et al., 2022), the coating speed, angle of disposition, and solution concentration play a crucial role to determine the ultimate thickness (Liang et al., 2021; Lundin et al., 2019; Padamata et al., 2022). Generally, it recommended developing the process in clean room environment to develop pristine surfaces. Previous works complemented the perovskite device fabrication, where dip coating technique was used to develop contact electron transport material layers. Compact TiO2 films were deposited using dip coating on FTO coated glass. The dip coatings of the samples were carried out manually for two, four, and six dips. The chemical solution was the mixture of titanium diisopropoxidebis (acetylacetonate) (Sigma-Aldrich) and isopropanol. All the as deposited samples were annealed in air at 450°C for 60 min. The films were structurally and morphologically characterized by X-ray diffraction and scanning electron microscope (SEM). The results showed crystalline, compact, stoichiometric growth of titanium oxide. The structural analysis of titanium oxide thin films was performed by X-ray diffractometer with different diffraction angle 2θ from 20° to 70°. The analysis shows the preferential growth of the film along the (101) and (004) directions of TiO2 phase with anatase structure (Du et al., 2022). The surface SEM images of titanium oxide layer on glass as deposited illustrate the nice full coverage of the films with less pinholes. Dip coating is not suitable for all coatings applications. A gradient of thickness can occur due to the variation throughout the entire surface. Hence, it becomes critical to control the immersion rate, viscosity of the source solution.
Post-processing treatments to enhance additively manufactured polymeric parts: a review
Published in Virtual and Physical Prototyping, 2021
F. Tamburrino, S. Barone, A. Paoli, A. V. Razionale
In general, the coating thickness and surface profile are highly influenced by coating material properties, such as viscosity and surface tension. However, process parameters also play a significant role, such as immersion and withdrawal speeds in the case of the dip coating technique.
Powder mixed-EDM for potential biomedical applications: A critical review
Published in Materials and Manufacturing Processes, 2020
Md Al-Amin, Ahmad Majdi Abdul Rani, Abdul Azeez Abdu Aliyu, Muhammad Al’Hapis Abdul Razak, Sri Hastuty, Michael G Bryant
The stability of HAP coating is a crucial factor for potential bio-implant since phosphate-calcium occupies maximum portion of the bone and teeth and provides bioactive responses. Moreover, the properties of HAP coating such as mechanical strength, corrosion-resistant behavior, and biological response are affected by various surface treatment methods.[201] Although numerous techniques of apatite and Ca-P-based ceramics deposition on the biomaterials have been reported, researchers are trying to developing new methods, called PM-EDM, which is proposed as a potential manufacturing process of the bio-implants. The deposition techniques are classified into two groups: chemical and physical deposition processes. The physical modification technique includes thermal spraying methods, pulse laser deposition, laser surface alloying, laser melting deposition, spray pyrolysis technique, and sputtering process. On the other hand, the chemical deposition method represents the following: sol-gel, hot pressing, dip coating, electrochemical deposition, electrostatic spray deposition, and electrophoretic deposition.[38,201] Among them, the plasma spray technique is commercially used in the manufacturing plants for depositing Ca-P-based coating on the implants. However, plasma spray requires intense heat for a higher rate of coating and a new technique is demanded to eliminate the limitation of the formation of an amorphous coating.[212] The sol-gel technique is familiar due to following a simple procedure and being economical which can produce higher strength coating compared to the bio-mimetic coating process.[235] But this process is unable to generate a porous surface. The dip-coating technique offers several benefits including lower set up cost, easy to use, ability to coat complex and irregular shape, uniform coating, and lower operating temperature.[213] Although both the chemical and physical techniques offer some advantages, they have various drawbacks, as well over the coating processes, surface quality, coating compounds and thickness, and production costing. Table 11 shows the basic advantages and demerits of existing surface deposition techniques.