High throughput discovery of thermo‐responsive materials using water contact angle measurements and time‐of‐flight secondary ion mass spectrometry

Layers of copper sulfides, CuxS, on the surface of a polypropylene film were formed by the sorption–diffusion method using two reducing agents – hydroquinone and hydroxylamine sulfate. The formed copper sulfide layers were investigated by UV/VIS, X-ray diffraction (XRD) and water contact angle measurements (WCA). The investigations confirmed that a layer of nonstoichiometric copper sulfide was formed on the surface of the polypropylene film. The water contact angle measurements revealed the change in adhesive properties of the samples after each treatment stage.

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Comparative Studies of Hydrogen Termination on Single-Crystal Silicon Surfaces by FT-IR and Contact-Angle Measurements

Applied Spectroscopy ◽

10.1366/0003702971939730 ◽

1997 ◽

Vol 51 (12) ◽

pp. 1905-1909 ◽

Cited By ~ 14

Author(s):

Oliver M. R. Chyan ◽

Junjun Wu ◽

Jin-Jian Chen

Keyword(s):

Contact Angle ◽

Water Contact Angle ◽

Silicon Surface ◽

Silicon Surfaces ◽

Crystal Silicon ◽

Water Contact ◽

Angle Measurements ◽

Contact Angle Measurements ◽

Hydrogen Termination ◽

Termination Process

The hydrogen termination process on a Si(100) surface has been studied by multiple internal reflection infrared spectroscopy (MIR-IS) and contact-angle measurements. Three main silicon hydride absorption peaks at 2087, 2104, and 2114 cm−1 were found to gradually increase with the hydrofluoric (HF) acid etching. Eventually, a constant peak height was reached as an indication of complete hydrogen termination. Integration of all the surface hydrides absorption peaks (2000 to 2200 cm−1) provides direct quantitative evaluation of the hydrogen termination process. On the other hand, water contact-angle data were shown to consistently lag behind the IR measurement in determining the extent of hydrogen termination on the silicon surface. Analysis of the surface free energy of HF-etched silicon surfaces indicates that the degree of the hydrogen termination determined by water contact-angle measurements is subjected to inaccuracies due to the preferential hydrogen-bonding interaction between the water and silicon surface oxide.

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Surface Characterisation of PEEK and Dentin, Treated with Atmospheric Non-Thermal PDD Plasma, Applicable for Dental Chair-Side Procedures

Plasma ◽

10.3390/plasma4030028 ◽

2021 ◽

Vol 4 (3) ◽

pp. 389-398

Author(s):

Marius Behnecke ◽

Vincent Steinert ◽

Svea Petersen

Keyword(s):

Contact Angle ◽

Phosphoric Acid ◽

Plasma Treatment ◽

Water Contact Angle ◽

Acid Etching ◽

Water Contact ◽

Angle Measurements ◽

Contact Angle Measurements ◽

Dentin Tubules ◽

Phosphoric Acid Etching

This study investigates the suitability of Piezoelectric Direct Discharge Plasma as a tool for wetting behaviour modification of PEEK and dentin, and compares the results of this method with low-pressure plasma treatment and phosphoric acid etching. Static contact angle measurements were made, roughness was assessed using tactile measurement, and AFM and SEM images were taken. An optimum operating distance of ≤15 mm was determined for the plasma based on the water contact angle. Furthermore, it was demonstrated that despite only a fraction of the power, the PDD plasma also produces hydrophilic and nanostructured PEEK surfaces with a 38° water contact angle in the same plasma time. In contrast, the gold standard of dental surface modification of dentin—phosphoric acid etching—showed no measurable contact angle due to the exposed dentin tubules. Treatment with PDD plasma reduces the water contact angle of dentin from 65° to 43° and is not negative affected by water. Wet, PDD plasma-treated dentin samples show a water contact angle of only 26.5°. The dentin tubules exposed by chemical etching led to a significantly increased roughness. No comparable effect could be demonstrated for plasma treatment on dentin, but based on the contact angle measurements, a chemically strongly activated surface with strongly polar interaction behaviour can be assumed. The additional use of the PDD plasma technique to improve wetting could therefore have a positive effect on the adhesive bond between human dentin and polymeric dental restorative materials or, depending on the adhesive system, replace the etching process altogether.

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