TECHNOLOGY/BUSINESS OPPORTUNITY All Liquid Two-Photon Polymerization Resin Formulations Using Cationic Polymerization

Opportunity:

Lawrence Livermore National Laboratory (LLNL), operated by the Lawrence Livermore National Security (LLNS), LLC under contract no. DE-AC52-07NA27344 (Contract 44) with the U.S. Department of Energy (DOE), is offering the opportunity to enter into a collaboration to further develop and commercialize its All Liquid Two-Photon Polymerization Resin Formulations Using Cationic Polymerization.

Background:

Radical photoresists are commonly utilized in two-photon polymerization (TPP); however, cationic photoresists have also garnered significant interest. The commercially available epoxy-based SU-8 serves as a prototypical cationic photoresist.  The parts of the SU-8 photoresist that are exposed to ultraviolet (UV) light becomes cross-linked while parts that are not UV exposed remain soluble. The resolution achievable with SU-8 in two-photon exposure is generally inferior in comparison to more advanced radical systems due to acid diffusion and the inability for oxygen to quench living cationic polymerization. To prepare for printing, SU-8 must be spin-casted onto a substrate,which limits the height of the printed part to a few microns. To advance cationic photoresist capabilities within TPP, a liquid resist is needed in order to print larger structures with fine resolution.

Description:

LLNL researchers have developed a liquid two-photon polymerization (TPP) epoxy based resin formulation capable of flowing under low load, which enables tall, centimeter-scale parts to be built using conventional TPP objectives with high working distance lenses. The unique photo-initiator chemistry helps to spatially control the extent of polymerization in the liquid resin improving print resolution and making it possible for cationic polymerization to be realized in TPP systems.

Compared to solid cationic resins, like SU-8 or the positive-tone resins which may not exhibit issues of over-polymerization, the described formulation requires an inhibitor and specific starting monomer viscosity to minimize acid diffusion and terminate the process to producing a well-controlled printed structure.

Advantages/Benefits: 

1. Epoxy based, all liquid, negative tone resin formulation capable of flowing under low load.
2. Capable of printing centimeter scale parts using conventional TPP objectives with high working distance lenses.
3. Able to achieve all liquid, optically transparent formulation which can result in high resolution, smooth surface 3D printed structures.
4. Provide an opportunity to enable multi-wavelength TPP capabilities since cationic polymerizations are orthogonal to free radical acrylate polymerizations.

Potential Applications: 

This invention can enable the fabrication of 3D structures with small feature sizes and large sample dimensions that could be used for

• battery, fuel cell, or electrolyzer electrodes
• photonic or phononic crystals
• mechanical metamaterials, microelectromechanical systems (MEMS)
• integrated circuit chips
• quantum information processors
• microfluidic devices.

Development Status: 

Current stage of technology development: TRL ☐ 0-2     ☒ 3-5     ☐ 5-9

LLNL has filed for patent protection on this invention.

Please visit the IPO website at https://ipo.llnl.gov/resources for more information on working with LLNL and the industrial partnering and technology transfer process.

Note:  THIS IS NOT A PROCUREMENT.  Companies interested in commercializing LLNL's All Liquid Two-Photon Polymerization Resin Formulations Using Cationic Polymerization should provide an electronic OR written statement of interest, which includes the following:

1. Company Name and address.
2. The name, address, and telephone number of a point of contact.
3. A description of corporate expertise and/or facilities relevant to commercializing this technology.

Please provide a complete electronic OR written statement to ensure consideration of your interest in LLNL's All Liquid Two-Photon Polymerization Resin Formulations Using Cationic Polymerization.

The subject heading in an email response should include the Notice ID and/or the title of LLNL’s Technology/Business Opportunity and directed to the Primary and Secondary Point of Contacts listed below.

Written responses should be directed to:

Lawrence Livermore National Laboratory

Innovation and Partnerships Office

P.O. Box 808, L-779

Livermore, CA  94551-0808

Attention: IL-13989