The objective of this research is to establish a knowledge base for a precision solid freeform fabrication process that creates polymer matrix nanocomposites that are fully functional as gradient refractive index lenses. Such lenses are flat rather than spherical. The project will seek to determine the principles behind forming gradient composites by inkjet deposition, and photocuring layer-by-layer from optically clear, photosensitized thermoset resins, which contain various amounts of well-dispersed nano-sized ceramic particles. The work will include selecting and combining the most appropriate polymer and ceramic nanoparticle components as well as determining the optimum conditions for inkjet processing and curing. It will also integrate the use of an optics design model in conjunction with the inkjet process. The design output then will be coupled with the printer driver. This is necessary for the fabrication of layers that have concentrations of particles in different locations in order to create the required refractive index gradients.
If successful, the research has the potential for ushering in an economical new type of flexible optic manufacturing. It will provide a platform for direct production of optics ranging from one-of-a-kind prototypes to full production runs without the need for grinding or polishing. Polymeric gradient lenses can be used in lens systems to reduce the number of elements by 25 to 50% with significant weight reductions. Since they will be more accurate, they also can be used to relax optical designs, lowering the sensitivity to alignment and fabrication errors. The combination of custom capability and cost-effectiveness may result in a sizeable market for this process. Moreover, the concepts developed in this program will be applicable to fabricating other nanocomposite systems, particularly structural composites reinforced with clays and carbon nanofibers. Using the same methodology with more robust matrix resin systems, such as aerospace epoxies, it should be possible to fabricate functional advanced nano-composites with enhanced modulus, strength and toughness characteristics.
