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About: Dip-coating is a(n) research topic. Over the lifetime, 7999 publication(s) have been published within this topic receiving 127362 citation(s). more


Journal ArticleDOI: 10.1038/38699
Yunfeng Lu1, R. Ganguli1, C. A. Drewien1, M.T. Anderson1  +7 moreInstitutions (2)
25 Sep 1997-Nature
Abstract: Thin films of surfactant-templated mesoporous materials1,2 could find applications in membrane-based separations, selective catalysis and sensors. Above the critical micelle concentration of a bulk silica–surfactant solution, films of mesophases with hexagonally packed one-dimensional channels can be formed at solid–liquid and liquid–vapour interfaces3,4,5. But this process is slow and the supported films3,5 are granular and with the pore channels oriented parallel to the substrate surface, so that transport across the films is not facilitated by the pores. Ogawa6,7 has reported a rapid spin-coating procedure for making transparent mesoporous films, but their formation mechanism, microstructure and pore accessibility have not been elucidated. Here we report a sol–gel-based dip-coating method for the rapid synthesis of continuous mesoporous thin films on a solid substrate. The influence of the substrate generates film mesostructures that have no bulk counterparts, such as composites with incipient liquid-crystalline order of the surfactant–silica phase. We are also able to form mesoporous films of the cubic phase, in which the pores are connected in a three-dimensional network that guarantees their accessibility from the film surface. We demonstrate and quantify this accessibility using a surface-acoustic-wave nitrogen-adsorption technique. We use fluorescence depolarization to monitor the evolution of the mesophase in situ, and see a progression through a sequence of lamellar to cubic to hexagonal structures that has not previously been reported. more

Topics: Mesoporous organosilica (61%), Mesoporous material (60%), Dip-coating (56%) more

1,362 Citations

Journal ArticleDOI: 10.1002/ADFM.200305036
Abstract: This article gives an overall view of the mechanisms involved in the mesostructuring that takes place during the formation of surfactant-templated inorganic materials by evaporation. Since such a method of preparation is well suited to fabricating thin films by dip coating, spin coating, casting, or spraying, it is of paramount interest to draw a general description of the processes occurring during the formation of self-assembled hybrid organic/inorganic materials, taking into account all critical parameters. The following study is based on very recent works on the meso-organization of thin silica films using tetraethylorthosilicate (TEOS) as the inorganic source and cetyltrimethylammonium bromide (CTAB) as the structuring agent, but we will show that the method can also be extended to other systems based on non-silica oxides and block copolymer surfactants. We demonstrate that the organization depends mainly on the chemical composition of the film when it reaches the modulable steady state (MSS), where the inorganic framework is still flexible and the composition is stable after reaching an equilibrium in the diffusion of volatile species. This MSS state is generally attained seconds after the drying line, and the film's composition depends on various parameters: the relative vapor pressures in the environment, the evaporation conditions, and the chemical conditions in the initial solution. Diagrams of textures, in which the stabilized structures are controlled by local minima, are proposed to explain the complex phenomena associated with mesostructuring induced by evaporation. more

Topics: Evaporation (56%), Dip-coating (54%), Spin coating (53%) more

713 Citations

Journal ArticleDOI: 10.1021/NN7003348
Joseph M. Luther1, Matt Law1, Qing Song1, Craig L. Perkins1  +2 moreInstitutions (1)
31 Jan 2008-ACS Nano
Abstract: We describe the structural, optical, and electrical properties of high-quality films of PbSe nanocrystals fabricated by a layer-by-layer (LbL) dip-coating method that utilizes 1,2-ethanedithiol (EDT) as an insolubilizing agent. Comparative characterization of nanocrystal films made by spin-coating and by the LbL process shows that EDT quantitatively displaces oleic acid on the PbSe surface, causing a large volume loss that electronically couples the nanocrystals while severely degrading their positional and crystallographic order of the films. Field-effect transistors based on EDT-treated films are moderately conductive and ambipolar in the dark, becoming p-type and 30–60 times more conductive under 300 mW cm−2 broadband illumination. The nanocrystal films oxidize rapidly in air to yield, after short air exposures, highly conductive p-type solids. The LbL process described here is a general strategy for producing uniform, conductive nanocrystal films for applications in optoelectronics and solar energy co... more

Topics: Nanocrystal (55%), Multiple exciton generation (51%), Dip-coating (50%)

699 Citations

Journal ArticleDOI: 10.1016/0040-6090(91)90158-T
05 Jun 1991-Thin Solid Films
Abstract: During sol-gel thin film formation via dipping, polymeric or particulate inorganic precursors are concentrated on the substrate surface by a complex process involving gravitational draining with concurrent drying and continued condensation reactions. The structure of films deposited from polymeric precursors depends on such factors as size and structure of the precursors, relative rates of condensation and evaporation, capillary pressure, and substrate withdrawal speed. Using polymeric silicate precursors, the porosity and refractive index of the deposited films may be varied as follows: volume percent porosity (0%–56%); pore radius (0–3.1 nm); surface area (1.2–263 m 2 g -1 ); refractive index (1.18–1.45). For repulsive, monosized particulate precursors, higher coating rates promote ordering of the particles as manifested by a reduction in porosity from 36% (random dense packing) to about 25% (f.c.c. or h.c.p.). more

Topics: Dip-coating (56%), Porosity (53%), Sol-gel (52%) more

586 Citations

Journal ArticleDOI: 10.1021/LA202877K
Jinhong Jiang1, Liping Zhu1, Li-Jing Zhu1, Bao-Ku Zhu1  +1 moreInstitutions (1)
08 Nov 2011-Langmuir
Abstract: This study aims to explore the fundamental surface characteristics of polydopamine (pDA)-coated hydrophobic polymer films. A poly(vinylidene fluoride) (PVDF) film was surface modified by dip coating in an aqueous solution of dopamine on the basis of its self-polymerization and strong adhesion feature. The self-polymerization and deposition rates of dopamine on film surfaces increased with increasing temperature as evaluated by both spectroscopic ellipsometry and scanning electronic microscopy (SEM). Changes in the surface morphologies of pDA-coated films as well as the size and shape of pDA particles in the solution were also investigated by SEM, atomic force microscopy (AFM), and transmission electron microscopy (TEM). The surface roughness and surface free energy of pDA-modified films were mainly affected by the reaction temperature and showed only a slight dependence on the reaction time and concentration of the dopamine solution. Additionally, three other typical hydrophobic polymer films of polytetrafluoroethylene (PTFE), poly(ethylene terephthalate) (PET), and polyimide (PI) were also modified by the same procedure. The lyophilicity (liquid affinity) and surface free energy of these polymer films were enhanced significantly after being coated with pDA, as were those of PVDF films. It is indicated that the deposition behavior of pDA is not strongly dependent on the nature of the substrates. This information provides us with not only a better understanding of biologically inspired surface chemistry for pDA coatings but also effective strategies for exploiting the properties of dopamine to create novel functional polymer materials. more

Topics: Dip-coating (56%), Surface energy (55%), Surface roughness (53%) more

517 Citations

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Topic's top 5 most impactful authors

Shahzad Naseem

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David Grosso

11 papers, 857 citations

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