BACKGROUND:  The most common way to make micro and nano scale particles of custom shapes is by lithography and etching, which requires expensive lithography masks, systems, and additional steps. Nanoimprintation, where a patterned form is pressed into a polymer to stamp out features, is an alternative for making customized particles. There are disadvantages to nanoimprintation, however, such as the form becoming clogged with polymer material, the enormous forces necessary to create enough pressure to stamp out very small objects, and often there is a residual layer of polymer that remains in areas outside the depressions where the form and flat substrate should make hard contact. Another popular option is "step-and-flash" nanoimprintation, where the form is used to stamp features into a photoresist, which is then exposed to light ("flashed") to crosslink. Less force is required in step-and-flash because photoresist is generally less viscous than molten polymer, but step-and-flash still carries the other disadvantages associated with conventional nanoimprintation.

INNOVATION:  The invention can fabricate particles without the need to stamp them out using a patterned form. Instead, the substrate itself is used to pattern the particles such that polymer merely has to be deposited, evaporated, and released to form custom shaped particles.

POTENTIAL APPLICATIONS 

• biomarkers, biological tagging or imaging, colloidal glasses, molecular probes, or anti-counterfeit security inks.

ADVANTAGES

• Reusable patterned substrate do not require lithography steps
• Simple implementation and high-throughput
• Easy release of the desired particles

RELATED CASES: 

• 2007-008 "Lithographic process for creating particles in a fluid"
• 2008-015 "Process for modifying surfaces of particles made using spatially patterned radiation"
• 2008-016 "Processes for relief deposition templating"
• 2008-017 "Fabrication of custom particles using relief radiation templating"
• 2008-018 "Variations of processes for making particles by spatially patterned radiation"
• 2008-019 "Processes for modifying particles made using relief deposition templating"

Reference: UCLA Case No. 2007-138