Tunable Multifunctional Nanomaterial and Polymer Composites: Nonwoven Applications

2015-07-21T00:00:00Z (GMT) by Joseph E. Mates
Functional nanomaterial and polymer composites are present in nearly every facet of our daily lives. A primary goal of this work was to enable many of the new composites and functional materials which we have developed to be scalable. One component which assists our pursuit of scalability, and therefore low-cost and high throughput, is our choice of substrates: nonwovens. Since much of this work involves modifying surfaces, a material with a greater amount of surface area is ideal for these pursuits. The initial focus of this work is in the arena of fluid management; more precisely, fluid repellency. We have developed environmentally-friendly water-based formulations to impart extreme water repellency, or superhydrophobicity. After characterizing this water-based system for the minimal mass deposition required, a novel fluid mechanism was subsequently discovered and characterized, termed the fluid diode, rectifying fluid flow in one direction. These developments later resulted in one of the first water-based and fluorine-free superhydrophobic dispersions. The knowledge gained in materials systems from the previous work enabled the extension of this research into conductive composites. By taking advantage of an ubiquitous material such as artists' acrylic paint and conductive graphite nanoparticles, a composite achieving quasi-metallic properties was achieved demonstrating extreme durability with competitive electronic performance; at a lower cost than current conductive inks and similar composite systems. This work was quickly followed by the development of another, extremely elastomeric conductive and superhydrophobic composite; making use of carbon nanofibers and another commonplace material found in nearly all modern laboratories: Parafilm. The performance far exceeds previous benchmarks from the literature in both flexible conductivity and repellency metrics, even after multiple stretch cycles. The final component to this work relies on a specific substrate, that of polyvinylidene fluoride (PVDF) nonwovens. The unique properties of the PVDF polymer enable exploration into the generation of piezoelectric fabrics for energy-harvesting and self-defouling filtration. In addition to the piezoelectric component, these materials were also characterized for water-in-oil emulsion separation; achieving, and surpassing in some cases, performance benchmarks from industry and literature for similar applications; thus, making this work a significant advance in relevant textile industries.