Hydrogen-bonded multilayers of self-assembling silanes: structure elucidation by combined Fourier transform infra-red spectroscopy and X-ray scattering techniques

Aluminum chlorohydrate I: Structure studies

The primary objective of this study was to fabricate a TiO2 nanotubular surface, which could maintain hydrophilicity over time (resist aging). In order to achieve non-aging hydrophilic surfaces, anodization and annealing conditions were optimized. This is the first study to show that anodization and annealing condition affect the stability of surface hydrophilicity. Our results indicate that maintenance of hydrophilicity of the obtained TiO2 nanotubes was affected by anodization voltage and annealing temperature. Annealing sharply decreased the water contact angle (WCA) of the as-synthesized TiO2 nanotubular surface, which was correlated to improved hydrophilicity. TiO2 nanotubular surfaces are transformed to hydrophilic surfaces after annealing, regardless of annealing and anodization conditions; however, WCA measurements during aging demonstrate that surface hydrophilicity of non-anodized and 20 V anodized samples decreased after only 11 days of aging, while the 60 V anodized samples maintained their hydrophilicity over the same time period. The nanotubes obtained by 60 V anodization followed by 600 °C annealing maintained their hydrophilicity significantly longer than nanotubes which were obtained by 60 V anodization followed by 300 °C annealing.

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Fabrication of Anti-Aging TiO2 Nanotubes on Biomedical Ti Alloys

Modifications of Ti–6Al–4V surface roughness, wettability and composition are increasingly studied to improve cellular viability on biomedical implants involving Ti–6Al–4V. In this study, it is shown that modification of Ti–6Al–4V samples using anodization (for the formation of titania nanotubes) combined with thermal oxidation (TO) results in superior surface characteristics to those of a smooth, rough, anodized-smooth or anodized-rough surface alone. Surface characterization is performed using water contact angle (WCA) measurements, white-light interferometry, Fourier transform infrared spectroscopy (FTIRS), field emission scanning electron microscopy and grazing incidence X-ray diffraction (GIXRD). WCA measurements before TO indicate that anodized-smooth and anodized-rough samples are super-hydrophilic (WCA less than 5°); WCA of non-anodized smooth and rough surfaces are 57 ± 6° and 86 ± 7°, respectively. After TO at 450 °C for 3 hours, all samples become super-hydrophilic; however, three weeks after TO, smooth and rough surfaces become hydrophobic, while anodized-smooth and anodized-rough surfaces remain hydrophilic. FTIRS and GIXRD data show that the TO of anodized and non-anodized smooth samples results in anatase and rutile TiO2, of which anatase is favorable for cellular attachment. Micro-/nano-scale roughness and TO are discussed in the context of enhanced Ti–6Al–4V surface characteristics for improved cellular response.

Enhancing surface characteristics of Ti–6Al–4V for bio-implants using integrated anodization and thermal oxidation

Thermally oxidized titania nanotubes enhance the corrosion resistance of Ti6Al4V.

Infrared spectra of aluminum chloride and aluminum hydroxide chloride solute species were determined using a Fourier transform infrared spectrometer. The solutions which were examined contained: aluminum chloride; an aluminum hydroxide chloride with an OH/Al ratio of 2.4, prepared by dissolving freshly prepared aluminum hydroxide gel in an aluminum chloride solution; and an aluminum hydroxide chloride with an OH/Al ratio of 2.5, prepared by reacting aluminum metal with an AlCl3 solution. Significant differences in the infrared spectra were observed. All solute spectra contained bands in the 2500 to 3100 cm−1 region for the stretch of water coordinated to aluminum, with the bands for aluminum chloride solutions most intense. In the bending region for Al—O—H, bands were observed at 970 to 1080 cm−1. The polymeric solute species also had absorption bands, although at different frequencies, in the OH stretch region, 3300 to 3700 cm−1, and in the frequency region from 600 to 800 cm−1.

http://journals.sagepub.com/doi/pdf/10.1366/000370278774331233

Diane A. Riesgraf

Papers

Infrared Spectra of Aluminum Hydroxide Chlorides