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Samples were biofunctionalized using plasma
Samples were biofunctionalized using plasma electrolytic oxidation on a custom-made laboratory setup. Details regarding the experimental setup can be found in [1]. Plasma electrolytic oxidation is an electrochemical process, which drives uniform growth of the titanium oxide (TiO2) layer on the surface of titanium biomaterials. The electrolyte contained 0.02M calcium glycerophosphate and 0.15M calcium acetate. Plasma electrolytic oxidation was performed for 0–300s under galvanostatic conditions.
The surface morphology was analyzed by a scanning AGI5198 microscope (JSM-IT100LA, JEOL, Tokyo, Japan). Analysis was performed with beam energies between 5 and 20kV and a 10mm working distance. Before analysis, specimens were cleaned for 30s in acetone and 2-propanol subsequently and coated with a gold layer of 5±2nm. Imaging was performed at 200, 500 and 1000-fold magnifications (Figs. 1–3).
Data
Experimental design, materials and methods
Acknowledgements
Data
Data in this article provides the dimensionless slip length and slip coefficient as a function of the fiber volume fraction for three different representative fiber packing structures in both longitudinal and transverse directions of fibers (Fig. 1). The fiber volume fraction is the ratio of fiber volume to the volume of a unit cell in the fibrous porous media. The dimensionless slip length is defined as with the slip length [m] and the fiber radius [m]; and the dimensionless slip coefficient with the slip coefficient [m−1] of Beavers and Joseph [1] and the permeability [m2]. For the quadrilateral packing structure, Table 1 is for the transverse direction and Table 2 is for the longitudinal direction. For the compressed hexagonal structure, Tables 3 and 4 contain slip length data for the transverse and longitudinal directions, respectively. Tables 5 and 6 list data on the slip length in each direction for the equilateral hexagonal packing structure. Table 7 describes the effect of the channel size on the slip length. In addition, we provided in each case the dimensionless void length , which is the measure of fractional free slip area at the fluid/porous interface (Fig. 1), and the normalized permeability . Plotted in Fig. 2 is bioluminescent the fitted dimensionless slip length and normalized permeability as a function of dimensionless void length in transverse and longitudinal directions for various fiber packing structures. Equation fitting is described in next section and in section 4.2 in Ref. [2].
Experimental design, materials and methods
Pressure-driven channel flows between a no-slip wall on the top and a fibrous porous media on the bottom were solved to estimate the slip length and slip coefficient, which is the most important parameter in describing flows within the dual-scale porous media. The Navier–Stokes equation is solved for the two problems: one is the computational solution for the actual fiber arrangement on the bottom and the other is the analytical solution with the effective slip boundary condition on the bottom. The slip length and slip coefficient can be evaluated by comparison of the two solutions. Extensive numerical simulations were performed to obtain the slip coefficient in the longitudinal (fiber) and transverse (normal to fiber) directions are presented as a function of various geometrical parameters of fibrous porous media including the fiber packing structure, the fiber volume fraction, the dimensionless void length and the normalized permeability. By the mesh refinement study, the accuracy more than three significant digits were ensured in estimating the slip length and slip coefficient. The three different fiber packing structures are presented in Fig. 1 and data includes slip characterization from very low volume fraction of fibers (0.15) to highly packed cases (up to 0.75 for the quadrilateral and compressed hexagonal packings; 0.85 for the equilateral hexagonal packings). From Ref. [2], the slip length and slip coefficient can be conveniently expressed as a master curve based on the dimensionless void length, which is determined directly from the fiber volume fraction and the structure of the porous media, and the relationship is given here for the completeness: