Flexible, lightweight nanocomposites for EMI shielding suppression in automotive applications

As technology advances, the need to place larger numbers of electrical and electronic systems into automobiles has dramatically increased. Metals are best suited as EMI shielding materials but their use comes with a weight penalty, have lower flexibility and low corrosion resistance make them unattractive for use in under-hood EMI shielding applications. The emergence of flexible conductive polymer composites has enabled the use of these materials for EMI shielding applications in the automotive industry due to their unique features such as lightweight, flexibility, strength,corrosionresistance,alongsidewithhighelectricalanddi-electrical performance. Traditionally, carbon black has been used to impart electrical conductivity and EMI shielding to polymer-based composites. However, the high loadings (20-30wt%) required to impart conductivity tend to degrade the overall mechanical properties of the composite. Several studies have shown that fiber-like materials, such as short-carbon fibers, carbon micro and nano- fibers as well as multi-walled carbon nanotubes demonstrate superior EMI shielding capability than carbon black, at much lower loadings. The ability to achieve equivalent or better electrical conductivity and EMI shielding at lower loadings enables preservation of mechanical durability and flexibility of the host polymer material thereby yielding a superior conductive plastic. These emerging composite materials are ideal candidates to provide EMI shielding for vehicle applications including but not limited to: under the hood electronics enclosures, cable/wire harnesses, and wraps. Applied Sciences Inc. (ASI) has established intellectual property on the synergistic benefits of adding macro-scale and nano-scale additives in polymer composites in which greater electrical conductivities were achieved at lower loadings than compared to individual macro and nano – scale additives. ASI will build on this foundational IP to develop a class of high-performance flexible polymer composite material with EMI shielding characteristics that meet or exceed metallic alternatives. The change from metallic to hybrid-scale polymer composites represents the ability to achieve the weight savings sought under the topic. Increased mechanical performance is also an expected outcome. In Phase I, ASI proposes to develop a flexible highly conductive polymer composite with EMI shielding characteristics. Fabrication and optimization of the polymer composite will be done at ASI. ASI recognizes that proper dispersion of the multi-scale carbon additives is critical for achieving high EMI shielding properties. Dispersion of the fabricated composites will be closely monitored by multi-scale image analysis (MSIA), a method developed by Dr. Leer-Lake, used to make quantifiable relationships between the carbon additives used to impart conductivity, the resulting dispersion and the measured electrical and shielding properties of the manufactured composites.