TriStar Plastics Corp. » hydrophobic

Hydrophobic Treatment for Foams

fhild — Thu, 28 Jan 2010 15:42:30 +0000

A recent development at TriStar – Surface Modification Division is a liquid surface treatment to induce a hydrophobic property. Most foam materials are very hydroscopic and absorbent. When our hydrophobic liquid surface treatment is applied to most foam materials, the foam becomes extremely hydrophobic. Below is an image of our treatment on medical grade polyurethane foam.

Though our tests indicate this treatment does not work well on natural materials like wood and cotton, but this treatment performs great on synthetic fibers and fabrics.

If you would like more information on this product, please continue to our website at www.tstar.com.

Surface Energy Design

fhild — Thu, 29 Oct 2009 09:00:08 +0000

Using simple plasma surface modification techniques, we are able to manipulate the surface of most plastic devices to contain fluids or direct flow.

Surface treatment zone

the surface treatment zone shown in the picture above is 0.9mm. The wet zones are hydrophilic drawing water into the narrow zone while the other areas are hydrophobic to the natural polystyrene material.

If you would like more information about this process, please vist our website.

Surface Roughness vs. Contact Angle

fhild — Wed, 25 Feb 2009 16:52:02 +0000

In surface science, the use of a goniometer (contact angle meter) is common to determine the wettability of a surface. What is clear is that every material has a specific surface energy. But, may not be clear is that the surface topography of that material also effects the contact angle.

Surface roughness can change the contact angle without plasma or other surface treatment. When a device is molded or machined, the surface finish of the device can have a functional as well as a aesthetic purpose. The functional purpose can be microscopic capillary channel as in microfluidic devices. The aesthetic purpose can be feel or finish of the part as in grips or sunglasses. The data below shows the effects of surface roughness in RMS versus natural, plasma treated hydrophilic, and plasma treated hydrophobic.

RMS	Type	Untreated	Philic	Phobic
16	Grind	80.0	24.5	108.0
32	Grind	85.0	31.0	113.5
63	Grind	92.0	30.0	112.0
125	Grind	99.0	29.0	115.0

Notice the general trends in contact angle relative to surface roughness.

What say ‘ye?

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