Category: LIFE SCIENCES
23. August 2012   4:42 pm
Jeff Leighty

Jeff Leighty
Elgin, IL

NASA has found yet another innovative use for plasma science. The Mars rover Curiosity is equipped with some cutting edge technology for analyzing the rocks as it rolls.

First, a laser shoots the rock with a million watts of power for 5 1-billionths of a second. The laser’s power excites atoms in the rock forming-you guessed it-plasma! Stopping there would be cool enough but NASA keeps going. A camera then analyzes the plasma to gather data on the composition of the rock. Repeated zaps on the same spot can reveal changes with depth in the rock’s composition. Together the laser and the camera have been dubbed ChemCam. What will they think of next?

For plasma applications on Mars call NASA. If your application is more Earthly in nature contact Plasmatreat! 855-4TH-STAT

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Khoren Sahagian

Khoren Sahagian
Materials Scientist

Editorial August 2012

Rocket propulsion has progressed in the over 40 years of space travel. On October 4th 1957 the Soviet Union launched the first artificial earth satellite. The feat was achieved using a 2 stage R-7 ICBM rocket weighing 170 tons. The solid rocket fuel needed to be held at cryogenic temperatures. Although today’s rockets are a lot more high tech most of the fundamental principles of propulsion still persist. Mainly the modern rocket typically utilizes solid rocket fuel. High altitudes are reached through multi-stage systems whereby the burned-out stage drops away relieving cumbersome mass from taxi of the final payload. Surprisingly the velocity with which space is traversed has not appreciably changed since the year 1962. This time of travel is arguably the biggest impedance to human exploration of the solar system. Second is that fact that once the rocket is ignited there is no turning it off; the fuel must be burned to completion. This is sort of suggestive of a one way trip. There is however a new generation of rocket propulsion beyond the horizon. The concept is named Variable Specific Impulse Magnetoplasma rocket or VASIMR.

 

The VASIMR is a plasma based propulsion system. Radio Frequency electric field ionizes the fuel into a plasma. Magnetic field then directs the hot accelerating gas out of the engine generating thrust. Even though the PTS and Plasmatreat organization utilize plasma for a different purpose, there are a couple of parallels that can be drawn. For starters one may envision mission specific gas mixture selection balancing metrics such as thrust, efficiency, and weight. Furthermore a plasma process may start or stop, its intensity regulated, and the gases employed are usually prevalent throughout the solar system. Efficient plasma impulse is ideal in the vacuum of space. There is great appeal in possibly being able to refuel a plasma propulsion system using gases present in the atmosphere of a destination such as mars. To put it in another perspective contemporary space shuttles exhausts propellant at about 6,000 m/s. An RF plasma would potentially expel mass in the range of 30,000 – 300,000 m/s. Here on Earth plasma has enabled myriad industrial and technological possibilities. I will finally conclude with an appropriate adage, “to the moon and beyond.” I am excited to see the field of plasma opportunity expanding into the stars.

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6. August 2012   4:53 am
Mikki Larner

Mikki Larner
Belmont, CA

Low pressure plasma is a controlled method for modifying the surfaces of materials. Our core competency is in modifying polymers. We’ve modified almost every type of polymer from silicones to fluoropolymers. These products range in size from nano-powders to 5 foot wide webs and membranes. Our company has been modifying life science materials for over 30 years. These include drug delivery platforms, fluidic devices, assay tools, ophthalmic Devices, implantable engineering polymers, stents, leads and their delivery devices.

The most practiced technology is activation (or functionalization) for subsequent adhesion attachment. In a functionalization process, the plasma species energy is used to break surface layer molecular bonds and leads to an altered surface chemistry. The plasma chemistry (and the substrate) drives the resulting functional groups.

Our laboratory includes 100s of different chemistries derived from gases and vapors from liquids. We’ve conducted sublimation work as well. The technology routinely is used for introducing chemistries that traditionally are conducted via wet chemistry. The technology offers tremendous controls and a short process cycle (< 15 minutes).

For the life sciences, typical functionalizations include:
• Hydroxyl
• Carboxylic
• Carbonyl
• Amine
• Vinyl
• Glycidyl
• Thiol

These groups can be closely coupled to a surface or distanced by chains.

Customers request these groups for attachment to:

• Amino acids, peptide attachment
• Coatings to resist biofilm attachment, coagulation
• Antimicrobials
• Biomolecular immobilizations
• Polyethylene Glycol (PEG)
• Hyaluronic acid
• Polylactic acid or polylactide (PLA)
• Surfactant coatings
• Hydrogels

We also practice thin film depositions (all organic). This process is called Plasma Enhanced Chemical Vapor Deposition (PECVD).

Typical coatings are around 40 – 4000 Angstrom thick. These coatings are dry. Coatings include:

• Polystyrene, Polyethylene
• Fluoropolymer, fluoroacrylates
• Siloxane (also via Openair)
• PEGylated (Tetraglyme)
• Aminated
• Polyacrylate
• Hydroxyethyl methacrylate (HEMA)
• Ethylene Oxide

Customers request these coatings for:
• Interfaces (or tie layers)
• Hydrophobicity
• Oleophobicity
• Lubricity/decreased COF (dry)
• Biocompatibility
• Functionalization
• Chemical resistance
to name a few.

Primarily we modify devices and this does include combination devices. As polymers are being used more and more for target therapies, plasma has become a viable means for modifying surfaces to change release capabilities or modify other surface properties.

The technology is versatile. Controlled. Inexpensive. There is no waste. It is environmentally and workplace safe.

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