Nexus Materials: A Vision Just Beyond the Horizon

Abstract

In future applications, materials will need to extend beyond that of the bulk response or even simple engineered behavior. This paper attempts to articulate an integrated vision and even push it further to the next realm of materials defined here as Nexus materials, the synergistic connection that weaves it all together. The applications in mind will demand complex functionality such as higher order actuation across surfaces/volumes, distributed conformal sensing, and full-spectrum instantaneous color change. Looking beyond the horizon, the level of complexity needs to be raised to radical state change (not just by a few percent) where the material properties can be grossly changed on command by electrical, magnetic, thermal, optical or chemical control stimuli. While it is desirable to have multiple states, the materials should be situationally functional with the ability to change key properties over time to economically accommodate changing situations- in contrast to current multifunctional materials that are time invariant. The research in nanomaterials holds the promise that one day it will be possible to design and build up materials from the bottom up into ultrahierachial systems like nature. It may be possible to achieve truly intrinsic intelligence with control and supporting elements such as power onsite via energy harvesting. However, the level of integration has to evolve beyond the discrete laminated structures of the 1990's and the discretely integrated composites of the 2000's to continuously integrated materials where the phases are indistinguishable. This doesn't mean no interfaces, but does implies minimizing the parasitic interfaces (typically extrinsic) and maximizing the helpful symbiotic interfaces (typically intrinsic). To achieve this vision, a new wholistic approach will be required that synergistically uses the design space, coupling multiple fields (piezoelectric, magnetostriction, shape memory, etc.). This alternative engineering paradigm will hopefully lead to new classes of material systems - Nexus materials - that make the ultimate, synergistic connection between the past and the future and are just beyond the horizon.