Ambient Temperature Conductive Ink Process
Researchers at the University of Illinois have developed a room temperature process to orient ink particles to enhance conductivity. This technology eliminates the need for the high-temperature curing process most conductive inks require to achieve maximum conductivity for switches, sensors, and semiconductors. High temperature curing is known to cause damage to other agents on the devices, such as proteins on enzymatic sensors, thus increasing manufacturing complexity and costs while making products of a lesser quality. The Ambient Temperature Conductive Ink Process allows the use of materials or agents that cannot withstand high temperatures and produces higher-quality products at a lower cost.
Description/Details
Ambient Temperature Conductive Ink Process involves a combination of new processes and new matter to attain a higher level of conductivity for carbon-based inks. The current process involves a high temperature curing procedure, which subjects the device to temperatures between 50 C to several hundred degrees Celsius. This often damages devices, rendering them useless, and increases production costs.
Furthermore, the ink that must be used cannot be used with popular ink-jet technology, necessitating the use of expensive equipment. Curing conductive ink at room temperature allows for the use of substances that cannot withstand even moderately elevated temperatures and to make superior products less expensively.
This process uses graphite ink with anisotropic properties to enhance conductivity. Upper limit conductivity is achieved after four to 16 hours of curing at room temperature. Typically, an increase in conductivity during ink curing is attained due to the aggregation of conductive particles above a percolation threshold. However, this technology's operating mechanism allows for the orientation of graphite planes, which gives the ink specific conductivity.
Applications
- Sensors: This technology has shown potential for biomedical sensor and chemical sensor production (particularly organic and inorganic multilayer sensors)
- Electronics: Membrane switches, flexible circuits, PCBs, Displays (touchkeys, touch screens, LEDs, electroluminescent displays), "Lab on a Chip" technology, and telecommunications interconnects that utilize conductive inks
Benefits
- More efficient and less expensive: The invention eliminates the high-temperature curing step.
- New materials enabled: Proteins and antibodies destroyed by curing can be used in this room-temperature process. Furthermore, polyethylene substrates can be used, which are ideal for printed circuit boards (PBCs) due to their insulating characteristics. The technique has potential to improve specific conductivity of composites incorporating conducting particles that have anisotropic shape or/and anisotropic electromagnetic properties.
- Versatile: Three options for enhancing conductivity (stretching, rubbing, and electrical orientation) allow the user to select the appropriate method for specific applications.
- Environmentally Friendly: By saving process steps, solvent consumption is minimized.
- Improving Miniaturization Techniques: This invention can be combined with existing micropen technology to increase conductivity in traces, allowing for smaller devices.
- Enhanced electronics: The ink's heightened conductivity is essentially one dimensional, enhancing electron mobility, lowering resistance, and operating temperature.