Extended asymptotic solutions to the spin-coating model with small evaporation

Cregan, Vincent; O’Brien, S.

doi:10.1016/j.amc.2013.07.071

Cited by 10 publications

(5 citation statements)

References 27 publications

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“…The thickness and uniformity of spin-coated films which are important parameters for their technological applications, depend on experimental conditions including; the spin time and speed, the viscosity of fluids, the density and the evaporation rate of the fluids, concentration of the suspension and the substrate surface characteristics. The flow behavior as a function of the fluid properties in spincoating process helps to recognize its strong performance in applications and has been investigated by many research groups through different models and experiments [2,3,5,[16][17][18][19][20][21]. Spin-coating of nano-colloids has been thoroughly explored in the literature for almost a century [1].…”

Section: Introductionmentioning

confidence: 99%

Spin-coating of moderately concentrated superparamagnetic colloids in different magnetic field configurations

Aslam

González-Viñas

2017

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Spin-coating technique is very fast, cheap, reproducible, simple and needs less material to fabricate films of particulate systems/colloids. Their thickness and uniformity may be controlled by means of external fields. We apply magnetic fields during the spin-coating of a moderately concentrated superparamagnetic colloid (made of silica coated magnetite particles). We study the influence of different magnetic field configurations (homogeneous and inhomogeneous) on the resulting spincoated deposits and compare experimental results under various conditions. Superparamagnetic colloids behave as, non-Newtonian, magnetorheological fluids. Their viscosity vary significantly under applied magnetic fields. We measure and compare the effect of uniform and non-uniform magnetic fields on their relative effective viscosity, using the spin-coated deposits and a previously existing model for simple colloids. The mechanisms involved in the deposits formation under different experimental conditions are also discussed. In particular, we show that the magnetophoretic effect plays an important role in the spin-coating of magnetic colloids subjected to non-uniform magnetic fields. We characterize an effective magnetoviscosity in non-uniform magnetic fields that is largely influenced by the magnetophoretic effect that enhances the flow of the magnetic fluid.

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Section: Introductionmentioning

confidence: 99%

Spin-coating of moderately concentrated superparamagnetic colloids in different magnetic field configurations

Aslam

González-Viñas

2017

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…To understand the spin-coating process, and to take from it the highest performance in applications, it is important to characterize the flow behavior as a function of the fluid properties. This has been studied through different models and experiments [2,3,5,16,[18][19][20][21]. Spin-coating of colloids has been thoroughly explored in the literature since the first half of twentieth century [1], specially in the case of nanocolloids for multiple applications in condensed matter.…”

Section: Introductionmentioning

confidence: 99%

Magnetorheology of hybrid colloids obtained by spin-coating and classical rheometry

Aslam

Shahrivar

Vicente

et al. 2016

Smart Mater. Struct.

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Hybrid colloids composed of micron-sized ferromagnetic (carbonyl iron) and diamagnetic (silica) particles suspended in cyclohexanone, behave as, non-Newtonian, magnetorheological fluids. We measure and compare the magnetic field-dependent viscosity of hybrid diluted colloids using spin-coating and conventional magnetorheometry. We extend a previously developed model for simple colloids to this kind of hybrid colloids. As in the previous model, the viscosity of the colloidal suspension under applied fields can be derived from the surface coverage of the dry spin-coated deposits for each type of particles, and from the viscosity of the colloid at zero field. Also, our results allow us to obtain the evaporation rate of the solvent as a function of the rotation speed. Finally, we also measure the viscosity of the same suspension with a torsional parallel plate magnetorheometer under uniaxial DC magnetic fields aligned in the velocity gradient direction of a steady shearing flow. The experimental results under different conditions and the effect of each component on the magnetorheological properties of the resulting colloid are discussed. Standard spin-coating technique can be used both to characterize smart materials-complex fluids as well as to fabricate films with arbitrary solvents by tuning their viscosity by means of external fields.

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“…Upon first glance at the 2D and 3D images, it might seem that there are not any significant differences between the samples, but the contour images expose different surface features more clearly. The most evident difference is in the apparent grain size of the particulate and mountain-chain-like surface features, which can be attributed to the different chemical properties of the respective final layers, as well as to the fact that during the spin-coating process the media evaporates at different rates73, influencing the respective sample morphologies. For the 3CHI2DCF-coated sample (Fig.…”

Section: Resultsmentioning

confidence: 99%

Novel chitosan/diclofenac coatings on medical grade stainless steel for hip replacement applications

Finšgar

Uzunalić

Stergar

et al. 2016

Sci Rep

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Corrosion resistance, biocompatibility, improved osteointegration, as well the prevention of inflammation and pain are the most desired characteristics of hip replacement implants. In this study we introduce a novel multi-layered coating on AISI 316LVM stainless steel that shows promise with regard to all mentioned characteristics. The coating is prepared from alternating layers of the biocompatible polysaccharide chitosan and the non-steroid anti-inflammatory drug (NSAID), diclofenac. Electrochemical methods were employed to characterize the corrosion behavior of coated and uncoated samples in physiological solution. It is shown that these coatings improve corrosion resistance. It was also found that these coatings release the incorporated drug in controlled, multi-mechanism manner. Adding additional layers on top of the as-prepared samples, has potential for further tailoring of the release profile and increasing the drug dose. Biocompatibility was proven on human-derived osteoblasts in several experiments. Only viable cells were found on the sample surface after incubation of the samples with the same cell line. This novel coating could prove important for prolongation of the application potential of steel-based hip replacements, which are these days often replaced by more expensive ceramic or other metal alloys.

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Extended asymptotic solutions to the spin-coating model with small evaporation

Cited by 10 publications

References 27 publications

Spin-coating of moderately concentrated superparamagnetic colloids in different magnetic field configurations

Spin-coating of moderately concentrated superparamagnetic colloids in different magnetic field configurations

Magnetorheology of hybrid colloids obtained by spin-coating and classical rheometry

Novel chitosan/diclofenac coatings on medical grade stainless steel for hip replacement applications

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