Page 111 - Handbook of Surface Improvement and Modification

106 Surface Tension and Wetting

other interesting examples of the effects of wettability on conductive polymer perfor-
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mance can be found in the review paper.
The effect of high density polyethylene, low density polyethylene and TiO nanopar-
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ticles on the poly(ethylene terephthalate)-rubber nanocomposite interface were investi-
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gated. The addition of TiO nanoparticles resulted in the decrease of the crystallinity
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degree, the increase of the surface roughness, and the largest increase in contact angle.
The waterborne polyurethanes with alkoxy silane groups in the side chains were syn-
thesized by the chain extension with diamine chain extender (3-(2-aminoethyl)aminopro-
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pyl)trimethoxysilane. The increase in silane content increased the hydrophobicity,
tensile strength, glass transition temperature, and thermostability, but decreased the crys-
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tallinity and elongation at break of WPU films.
The effect of acrylonitrile content on morphology, compatibility and mechanical
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properties of polylactide and acrylonitrile butadiene rubber blends has been studied. The
rubber particle size decreased when acrylonitrile content was decreased because the inter-
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facial tension decreased along with a decrease in acrylonitrile content. All blends had
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similar glass transition temperatures and crystallinities.
The thermoplastic polyurethane film sprinkled with nanosilica particles was heated
o
o
to 120 C (below the polymer melting temperature (145 C) and above the hard segments
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glass transition (66 C)), for 15 min. This treatment was sufficient for particles to sink
into polymer matrix (Figure 7.10) increasing surface roughness by 621% and surface free
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energy by 45%. Improved wettability significantly improved printability of inkjet con-
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ductive ink.
Branched polyglycerols were used as performance additives for water-based flexo-
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graphic printing inks used for printing on polyethylene film. The addition of polyglycer-
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ols improved the wet and rub resistance of water-based flexographic printing. Even a
small addition of glycerol ethoxylate (0.01 mass fraction) improved the wettability of
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ink.
Wettability of polymeric biomaterials plays an important role in medical devices,
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implants, drug delivery systems, diagnostic assays, and bioreactors. The book chapter
discusses many relevant aspects of wettability of polymers used in the medical devices
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including their modification methods and mechanisms of action.
The nanofluids or hybrid nanofluids have gained interest in many engineering fields
(including refrigeration and air conditioning) due to their excellent thermophysical prop-
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erties. The nanofluids can be used in the refrigeration systems as refrigerants, lubricants,
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and secondary fluids. The review paper discusses these applications.
The adhesion force between an atomic force microscopy tip and the natural fiber sur-
face was used to estimate the water contact angle and surface wettability of the fibers. 28
Atomic force microscopy adhesion force measurements on natural fiber samples gave the
highest readings on more polar samples such as steam-alkaline treated fiber, and the low-
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est on the less polar samples such as acetylated and untreated fibers.
When a ski glides on snow, the friction between the sole and the snow creates a water
film whose thickness is usually controlled by ski base surface roughness and gliding
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wax. The fluorine-based additive (Genolub PFH 1020) was added to paraffinic ski glid-
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ing wax to improve its performance. The wettability and penetrability increased between
0% and 4%, then decreased between 4 and about 10%, and remained constant from 10 to