Market Overview:
This cellulose-based film offers a more environmentally friendly and cost-effective alternative to silicon for microelectromechanical systems (MEMS). To date, silicon has been the material of choice for MEMS devices, with a current market of $14 billion that is expected to grow to $20 billion by 2020. However, silicon MEMS have significant disadvantages. Silicon is facing increasing supply constraints and is generally regarded as expensive and environmentally detrimental due to energy intensive processing with harsh chemicals. To overcome the disadvantages of silicon, Clemson University and Auburn University researchers collaborated to develop cellulose films as an alternative material for MEMS devices and sensors. Films derived from cellulose are considered an environmentally friendly alternative to traditional MEMS materials based on the benign nature of the material, similarities in surface chemistry to that of hydrophilic silicon oxide and similar mechanical properties to that of silicon.
Application Stage of Development
MEMS, sensors, consumer electronics, defense and communications Proof-of-concept
Advantages
• Requires less energy for production, decreasing manufacturing costs
• Reduces the use of harsh chemicals, providing a safer alternative to silicon
• Uses abundantly available, biocompatible materials, reducing environmental impact while decreasing
production costs
Technical Summary
Cellulose is a naturally abundant, renewable, and biodegradable material. Cellulose nanocrystal (CNC) films can be fabricated into MEMS devices with novel properties using simple fabrication techniques. With reduced process temperatures ranging from 25-80⁰C and the use of solvents such as isopropanol to replace hazardous reagents, CNC films are lower cost and greener than silicon. Additionally, CNC MEMS combine the advantages of silicon and polymer MEMS while also providing new potential functionalities. This approach has more desirable physical properties (e.g., intrinsic elastic modulus and thermal stability) then polymer materials and can be processed using conventional lithography and wet etching techniques (unlike polymers).
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Inventors: Christopher Kitchens, William Ashurst, Virginia Davis
Patent Type: Utility
Patent No: 9,353,313
CURF Ref No: 2013-015