Weiheng Xu | School of Engineering

A recent study by Boston University suggests that 99 percent of the deceased National Football League (NFL) players were diagnosed with chronic traumatic encephalopathy (CTE), a progressive degenerative disease that is often associated with repetitive brain trauma. Current commercialized helmet designs, such as Xenith X1, Riddell Revolution Speed, and Schutt Ion4D each offers unique protective structural models such as internal suspension system. On the other hand, academia researches focusing on efficient damping polymer-nanoparticle composites are rarely commercialized due to high cost and difficulties regarding mass manufacturing. However, this seems to be coming to an end with the advancements in additive manufacturing. It allows customized products for individuals as well as incorporating functional particles in the micro- and nano-regime. The bottom-up process also guarantees a competitive cost that meets the industrial standard. This proposal aims to investigate towards a 3D printed micro- and nano-level featured polymer substrate structure with controllable self-impregnated nanoparticles for energy damping, impact detecting, and monitoring, or drug delivery. The experimental design of the proposal is, (a) 3D printing of substrate, (b) nanoparticle self-impregnation, (c) hierarchy structure assembly with posttreatment, and (d) performance testing. Customized laser/light projection-based 3D printers (XY resolution ~ 5 micrometers) will be used to print substrates with various patterns. Through impregnation methods such as dip-coating, spin assisted, capillary force, and surface tension, nanoparticles would attach to the substrate in a self-assembling manner. Factors such as dispersion quality, nanoparticle concentration, temperature, pressure, and solvent-substrate compatibility will be studied to analyze particle-substrate interphase/interface interaction, particle alignment, loading capacity, and stability. The substrates would then be assembled with controlled geometry and void concentration to form a hierarchy porous structure to maximize damping efficiency, protecting the body from impacts. Last, the assembled structure would be integrated with current sport wears, and the nanoparticle types determine the associated functionalities. For instance, carbon nanotube/carbon black polymer composite often display piezoresistive effect, a change in electrical signal upon structural deformation. By recording the signal, the magnitude and frequency of a player is impacted in the head during games or practices can be studied. By changing the nanoparticles with drug-loaded core-shell nano-rods, the substrate can be printed with personalized site-specific shape, more efficiently covers the wounded area. Core-shell structure could control drug release rate, minimizing medical attention during the healing period, especially where surgical are needed. (388

Last Updated February 2020.