Plasma Treatment Basics for Coatings

Posted by Josh Simon on Fri, May 25, 2012 @ 09:04

I would like to point out a great talk given by my friend Mikki Larner over at Plasma Blog which gives an easy-to-understand rundown of the basics of plasma treatment of surfaces.  For those new to this whole thing, not all hydrophilic coatings will stick to all surfaces.  In order to get a hydrophilic coating to adhere to a surface, some materials require that you treat them with energized plasma (i.e. the fourth state of matter), which functionalizes or at least charges the surface to provide the chemistry necessary to make the coating stick.

The paragraph above is greatly simplified, but this video describes the process in more detail.

 

Often, some sort of test will follow the coating process, such as pinch testing.

Click me

Tags: surface preparation, plasma treatment, Plasma Treatment Systems, surface modification

Coatings odds and ends - From pinch tests to trade shows

Posted by Josh Simon on Thu, Feb 23, 2012 @ 01:46

There has been a flurry of activity this year that I am working to keep up with. 

Quite soon, I will be releasing an entire white paper based on my earlier blog article here, 5 Critical Questions to Ask About Pinch Testing. Do not worry about missing the release because you will see an announcement here, plus a press release, most likely.  From either of those sources you will be able to download the article.

We also just got back this week from the MDM West show in Anaheim, CA. With regard to hydrophilic coatings and related subjects, there was a lot of activity there.  Although I must note that Bayer's hydrophilic coating was conspicuously absent from their booth.  Maybe they finally read my blog articles on Hydrophilic Coating Market Size? There were also a few nice talks on plasma treatment of surfaces before coating, and another talk on cardiovascular-based applications by Dr. Ron Sahatjian of Medi-Solve.  To be honest, I could not attend either talk due to the traffic at my booth, and the schedule of meetings I kept that week.  If anyone wants to remark on them, feel free.

This is a little shot of the "Biocoat crew" from the show.

Biocoat Hydrophilic Coatings

Left to Right:  Dhruv Patel, Peg Beavers, Keith Edwards, Josh Simon

Tags: pinch tester, medical device development, hydrophilic coatings, MDM West, hydrophilic coating market, hydrophilic coatings blog, pinch testing, plasma treatment

Plasma Treatment for Adhesion of Lubricious Hydrophilic coatings

Posted by Josh Simon on Mon, Nov 28, 2011 @ 09:18

Today's article comes to us from Drs. Demetrius Chrysostomou and James Bond from PVATepla.  It is an informative read on plasma treatment for hydrophilic coatings:

Catheters are inserted into the body for fluid drainage, duct dilation and drug/nutrient delivery.  With an invasive device the host’s health can be compromised due to tissue trauma and subsequent infection. Hydrophilic coatings are beneficial in reducing trauma damage. However, some catheter polymers can be classified ‘difficult to coat’ and the adhesion is far from optimal.  Good adhesion of the hydrophilic coating is essential. Poor adhesion could lead to shedding of the coating in vivo and increase the risk of coronary embolism.    This is where plasma can play an important role

What is plasma?

plasma

Plasma is a gas energized to a state of electrical conductivity. Chemically it is a highly reactive environment that is used to change the properties of surfaces without affecting the bulk material. Plasma is a powerful tool in solving surface preparation problems such as precision cleaning and decontamination, increasing surface wettability and adhesion promotion of functional bio-molecules and coatings. Plasma can also be used to polymerize coatings onto surfaces through a technique called Plasma Enhanced Chemical Vapor Deposition (PECVD). The main advantage of plasma as an enabling technology is that it is a clean dry process. As such there are none of the liabilities of wet chemistry, such as leaching toxic solvents.

Historical use of Primers for Surface Activation

Historically primers have been used to activate ‘difficult polymer’ surfaces. Some primers are considered hazardous.  There may be primers are highly toxic, caustic, carcinogenic and are potential leachables. The EPA and FDA review medical grade primers and the trend is to remove particular primers from the ‘safe to use list’. An example of the chemical primer used for PTFE and ePTFE is TetraEtch (a mixture of sodium, naphthalene and 1,2 – dimethoxyethane). This primer is teratogenic, toxic and caustic.  

plasma schematic

Plasma prepares the surface by molecular cleaning.  Specific chemical groups are then grafted by a second plasma step.  The surface is then exposed to the functional molecules that chemically bind to the plasma grafted moieties.

ePTFE use for medical devices

Expanded polytetrafluoroethylene (ePTFE) is a commonly used material for implant applications. It’s mechanical strength, impermeability to blood and inertness to bio fouling make ePTFE ideal for such in-vivo applications. Its flexibility aids in healing, and catheter tubing doesn’t kink very easily and generally has good compression resistance. For biomedical applications the ability to modify PTFE surfaces is important to promote interfacial biocompatibility.

 

Plasma treatment of ePTFE for binding lubricous coatings

 It is possible to graft polar functional groups to PTFE by plasma activation. These polar functional groups act as excellent anchor to covalently bond hydrophilic coatings. The PVA TePla plasma surface activation for ePTFE is an environmentally friendly alternative to primer treatment. We treat parts in a highly controlled low temperature, low pressure dry, clean gas environment such as the IoN300 catheter treating tool below.  

plasma machine

What does PVA TePla America offer?

 PVA TePla America offers a solutions based team of chemists (physical, surface, organic and bio-chemist) who will work with you or your chosen coatings company to find the very best surface treatment for you polymer. We offer free proof of process as an incentive to evaluate our plasma technology. We have clean area contract processing capability with ISO 9001:2008 certification. And we offer a full range of vacuum and atmospheric gas plasma systems. PVA TePla America is based in Corona, CA. www.pvateplaamerica.com

 

For further information contact  [email protected] (951) 415-0391

 

 

 

 

 

 

Tags: coating equipment, PVATepla, lubricious coatings, hydrophilic coating on teflon, plasma treatment