229. PROTECTION DAMPING BY NANOPOROUS MATERIALS FUNCTIONALIZED LIQUID
Name: Weiyi Lu
Grad Year: 2011
Taewan Kim, email@example.com
Protection by nanoporous materials functionalized liquid
Traumatic brain injury (TBI) and blast lung injury (BLI) are signature injuries of the Iraq war. About 30% of the soldiers deployed in the battlefield suffer TBI and/or BLI, which significantly affected their quality of life, their families, and the healthcare providing system. Conventional helmets and armors were designed to prevent penetration injuries. It has been proven in the battlefield that they failed to mitigate TBI/BLI. One major problem of conventional protection materials, such as EPP and EPS, is that they do not react fast enough as an external loading is applied. At a blast front, the pressure rises to the peak value in a few microseconds, while the energy absorption mechanisms of a conventional protection material (e.g. cell buckling) take a few milliseconds, 1000 times longer. Thus, although the overpressure plateau following the blast front can be reduced, the front itself can directly pass through the protection layer as if it were ?transparent?. In order to develop TBI/BLI mitigation materials, we investigated nanoporous materials functionalized (NMF) liquids. A NMF liquid is a liquid suspension of nanoporous particles. The inner surfaces of nanopores are specially treated to be hydrophobic. With the aid of an external pressure, the liquid phase can be intruded into the nanopores. As the liquid passes the ultra-large pore surface (~1000 m2/g; that is, in one gram of NMF liquid, the surface area is equivalent to half of a football court), tremendous amount of energy is dissipated. The energy dissipation is ultra-fast, which is completed in a few microseconds, ideal for mitigating blast fronts. The liquid motion in nanopores is a new scientific area, to understand which we investigated a variety of nanoporous structures and the infiltration pressure. The infiltration pressure determines the initial point of damping which is varied with the pore size of the nanoporous material and surface treatment agent. The raw material is heated with R4-nSiXn where R is an n-alkyl chain CnH2n+1, X is Cl. For micro- and meso- porous materials, TMCS is efficient to cover the original surface of the raw material. However, the infiltration pressure is usually as high as 25Mpa. For pore size over 50nm, octyldimethylchlorosilane and RSiCl3 are much better than TMCS. The infiltration pressure can reach the level lower than 2MPa.