A rapidly expanding research frontier is the fluidic manufacture of anisotropic particle building blocks. Simultaneously, the concept of encoding information into the sequence, shape and symmetry of anisotropic particle building blocks so they can assemble into complex three-dimensional (3D) structures offers tremendous potential. Taken together, these two areas each represent one level of a new hierarchical assembly paradigm that can input spherical nanocolloidal precursors and, by way of anisotropic building blocks, output complex 3D terminal structures with a range of new, active functionalities. Yet, to date, the two levels of the assembly hierarchy have advanced independently on the different scales of microparticles (fabrication) and molecules (anisotropic assembly) rather than together at the nanoscale. In this project we seek to address the key fundamental scientific challenges needed to realize this hierarchical paradigm at nanoscale dimensions where there is rich new potential for applications requiring active functionality for materials in photonics, electronics and energy management. In this aim we are supported by our recent discovery that fluidic processing can be used to assemble microparticles into permanently bonded anisotropic building blocks with high sequence and shape fidelity. Our prior research has additionally shown vis simulation that anisotropic building blocks are a key foundation from which 3D terminal structures can be assembled. Building on this experience in fluidic manufacturing and anisotropic particle assembly, our work plan is organized to address four key fundamental science and engineering design questions that arise as the hierarchical assembly paradigm is extended to the nanoscale. First, to address the potential for fouling in nanofluidic channels, as particle size is reduced into the nanoscale range, we will study how anisotropic building blocks interact with fluidic channels of complex design. Second, we will harness this understanding to discover the fluidic designs that optimally produce building blocks of novel sequence, shape and chirality. Third, given that a suite of such novel building blocks are now available, and that a given complex 3D terminal structure has been targeted for assembly, we will search for optimal ways to design the anisotropic building blocks for self- and guided assembly. Finally, we will discover how to execute self- or guided- assembly operations so as to achieve the target structures from the manufactured building blocks. These objectives, each with intrinsic intellectual merit, will be addressed through an integrated research program that brings to bear our state-of-the-art capabilities in nanofabrication, fluidic manufacturing, nanocolloid assembly, direct visualization by confocal and electron microscopy and computer simulation of anisotropic building block interactions and assembly. Simultaneously, by developing new data repository and wiki cyber tools within the National Science Digital Library framework, we will create a clear conduit for dissemination of our discoveries so as to contribute to the integration of the broader national nanoscale science and engineering community, to the training and education of our students and to the improvement of the participation of underrepresented groups and low to moderate income students from the southeastern Michigan area. The broader impact of our work will be to advance the national effort in nanoscale science and engineering by creating underlying scientific understanding that enables the penetration of fluidic manufacturing and anisotropic building block assembly into the nanocolloidal size regime where potential applications are richest. Furthermore, by creating new avenues for research dissemination and learning through the framework of data repositories and wikis, we can further integrate the national research communities, our students and our region into the exciting research frontier of nanofluidic manufacturing and anisotropic building block assembly.
