Tuesday, July 27, 2010

Oceanit Laboratories Carbon Nanotubes-Reinforced Conductive Silver Ink

Oceanit Laboratories, Inc. (Honolulu, HI) earned U.S. Patent 7,763,187 for a conductive silver ink that is reinforced using carbon nanotubes. Carbon nanomaterials are stabilized and uniformly dispersed in a solvent and mechanically mixed with conductive silver ink. The reinforcement material bridges the gap between separated silver flakes in the conductive silver ink. The carbon nanotubes reinforced conductive silver ink exhibits superior performance over unreinforced silver ink in its mechanical, electrical and thermal properties without significantly greater weight, according to inventors Vinod P. Veedu and Christopher J. Sullivan.

Conductive adhesives technology has many exciting advantages: they are compatible with a wide range of surfaces (including those that are non-solderable), have low thermal stress during processing, wide processing latitude, easy process control, and they demand only minor pre-clean or post-clean requirements. However, in general, conductive adhesives suffer due to lower mechanical strength and fatigue life and higher electrical and thermal resistance.

A need exist for improved conductive inks and coating with improved conductivity and adhesion, mechanical and fatigue properties.

The invention reinforces conductive silver ink with carbon nanotubes (single walled, multiple walled, functionalized, as prepared or purified). Theoretically, metallic nanotubes can have an electrical current density more than 1,000 times greater than metals such as silver and copper. Moreover, carbon nanotubes exhibit extraordinary mechanical properties--the Young's modulus is over 1000 Giga Pascal and the estimated tensile strength is 200 Giga Pascal. These properties are ideal for improving the electro-mechanical performances of nanocomposites in general and silver conductive inks in particular. The carbon nanotubes are uniformly dispersed in the silver ink using a dispersion process by means of a solvent. 

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