BACKGROUND:  Known electrodes, such as aluminum electrodes used in the capacitor industry, can be self-cleared. Self-clearing deactivates defective portions of the electrode, allowing remaining portions of the electrodes to remain functional. Due to the highly conductive nature of aluminum electrodes, an electric arc can vaporize portions of the electrode surrounding the defect. This process requires energy consumption as high as the evaporation energy of aluminum. However, unlike aluminum electrodes, solution-processable electrode materials are not highly conductive, so they typically do not vaporize by electric arc. The conductivity of the materials can be cleared through thermally-induced degradation or reorganization.

INNOVATION:  Dielectric devices using self-clearable electrodes are reliable with graceful failure. Self-clearable compliant electrodes are processed from solutions at ambient temperature. The electrodes are ultrathin, are semitransparent, and remain moderately conductive even after high mechanical strains. The clearing is stable, reproducible, and not sensitive to electrode thickness or conductivity. Improved adhesion between polymer film layers provides higher mechanical stability as a result of the films coherently reinforcing each other. Thus, slow clearing can be performed even during an actuation process while the electrodes are under mechanical strain.

POTENTIAL APPLICATIONS 

• Mechanical actuators, i.e., self-healing "artificial muscles"
• Organic compliant electrodes with enhanced reliability

ADVANTAGES

• Achieves enhanced breakdown strength by self-clearing
• Improves production yield, actuator performance, and reliability
• Eliminates catastrophic failure modes due to dielectric breakdown
• Reduces the cost, weight, and volume of electrode material
• Reduces driving voltage
• Enables graceful failure

DEVELOPMENT-TO-DATE:  The invention has been experimentally tested and verified. Using the new electrode materials, actuation strain greater than 100% has been achieved with enhanced fabrication yield and reliability.

Reference: UCLA Case No. 2007-143