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Up To 28% Functionalisation Through Dry Plasma HDPlas Process Offers Environmentally Friendly, Scalable Alternative to Graphene Oxide

Posted By Graphene Council, Thursday, August 13, 2020
Haydale is a world leader in plasma treatment and nanomaterial functionalisation through its HDPlas process. This process sees sophisticated plasma reactors deliver tuneable levels of functional groups, chemically bonded to substrate surfaces. Using various types of plasma that confer different surface chemistries, including cleaning plasmas for targeted removal of chemical contaminants, 3- dimensional treatment is directed only at exposed surfaces, thus maintaining structural integrity.

Haydale uses its patented plasma process to develop bespoke solutions with varying levels of plasma treatment and functionalisation. Properties can be adapted to develop hydrophilic, hydrophobic, carboxylic, amine and oxidative modifications to a range of materials. These modifications improve the treated material’s incorporation into advanced materials. Currently, Haydale has plasma-treated over 250 different types of material that it has characterised and fingerprinted, enabling specific properties to be targeted in future projects.

Historically, Haydale has been able to provide a functionalised process through the dry plasma HDPlas process with maximum fuctionalisation levels of 21%. The existing graphene oxide market offers a material with traditionally 25 atomic percent oxygen atoms. Graphene oxide is produced by wet chemistry processes; this has issues with scalability and the length of time to produce a batch of material taking days. Typical methods involve environmentally hazardous by-products and unstable intermediates (potentially explosive). Graphene oxide is used for batteries and capacitors as well as in flexible electronics, solar cells, chemical sensors and bio-sensing and as an antibacterial defence.

Having a stable plasma process treating extremely conductive material is challenging, especially in a commercial and scalable process. Having already achieved 21% functionalisation through its scalable process, Haydale has a sound base on which it can build to increase the surface chemistry levels by having a more effective and efficient plasma and chemistry. Having a more powerful plasma means improving the engineering solutions. This includes, but is not limited to, the electrode, gas control systems, power delivery and generation, reaction barrel and chamber and materials of construction. By refining the design and implementing novel components that are bespoke for the application, the plasma can be further enhanced.

Haydale’s primary focus in enhancing the functionalisation levels are improved chemistries, including the feed of the process chemistry and potential mixed chemistry and staged functionalisation treatments. The system operates at a vacuum; the process chemistry is bled into the reaction chamber and, once the treatment parameters are established, the plasma can be struck.
 
In developing the 28% treatment levels, the above system, chemistries and processing conditions all need to be balanced to ensure a stable, non-arcing and repeatable process, as well as achieving the required output. As the effectiveness of the process increases, so does the aggressiveness of the plasma. If this is not balanced with the above parameters, arcing can occur; this means a sustained spike in electrical current that could lead to a thermal plasma which could be damaging to both the reactor and the material. The main outcome of this is a less effective treatment. Current is controlled by a combination of electrical interlocks and a well-balanced process.

Nonetheless, Haydale has been able to balance all of the above and achieve a repeatable and accurate treatment of levels that are comparable of the wet chemical methods of graphene oxide production. Verified in a letter of support by the Cardiff University, 28% Atomic Percent oxygen has been measured, targeting the existing graphene oxide market. No solvents or harsh chemical treatments are used in this dry and environmentally friendly process and a scalable proven process is already used in industry. This new system can also apply to Haydale’s other properties (hydrophilic, hydrophobic, carboxylic, amine etc.) providing the same environmentally friendly, scalable process now with even more surface chemistry.

Tags:  Graphene  Haydale  nanomaterials 

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