The dissertation systematically delineates the mechanically-guided deterministic assembly of three-dimensional (3D) mesostructures by compressive buckling, covering topics from mechanics concepts, design and analysis, fabrication techniques, to application opportunities. The development of approaches to form complex 3D functional mesostructures in advanced materials is a topic of broad interest, thanks to the ubiquitous applications across a diversity of technologies. Previous options in forming 3D mesostructures are, however, constrained by a narrow accessible range of materials or 3D geometries. A versatile class of schemes in the mechanically-guided 3D assembly allows deterministic transformation of two-dimensional (2D) structures into sophisticated 3D architectures by controlled compressive buckling resulted from strain release of prestretched substrates. Maintaining full compatibility with lithography-based planar technologies, these approaches work seamlessly with nearly any class of thin-film materials (e.g., semiconductors, metals, and polymers) and across length scales from nano to macro, in a parallel, high-throughput fashion. A broad class of strategies has been demonstrated to enhance the geometric diversity of accessible 3D mesostructures. (1) A Kirigami-inspired approach enables the deterministic assembly of 3D mesostructures of diverse materials from 2D micro/nanomembranes with strategically tailored geometries and patterns of cuts. (2) Concepts for engineered substrates with tailored distributions of the thickness or with heterogeneous integration of materials of different moduli offer a viable route to spatially nonuniform prestrain fields for targeted control over resultant 3D geometries. Large strain gradients and effective strain isolation/magnification, challenging to realize by previous strategies, can be conveniently achieved. (3) Integrating components of physically transient materials onto 3D mesostructures achieves triggered evolution of 3D geometries, as a form of four-dimensional (4D) assembly. (4) Adopting mechanical interlocking elements to irreversibly “lock-in” the 3D shapes during the process of mechanically-guided assembly accesses freestanding 3D architectures. A broad collection of complex 3D mesostructures of various materials (semiconductors, metals, and polymers) is demonstrated, including examples that span a diverse range of critical dimensions, those that resemble jellyfish, windmill, or scorpion, and those that have application potentials in tunable optics, tunable electronics, or vibrational microsystems. Notably, 3D electronic scaffolds for cells and tissues, and 3D biomimetic microvascular networks represent two of the many unique, essential implications of the mechanically-guided approach for 3D bio-integrated functional systems. Both functionalities can be accessed through the 3D assembly approach in a deterministic manner. Flexible 3D electronic scaffolds with precisely defined geometries and microelectrodes distributions can be integrated, through well-defined volumetric spaces, within engineered 3D cardiac tissues to achieve an enhanced level of monitoring and regulation of tissue function. 3D artificial microvascular networks are vitally essential in transporting oxygen and nutrients and providing long-term, intimate interfaces for engineered, hierarchical cells and tissues. All these research insights and findings presented in this dissertation will hopefully illuminate the future development of high-performance, multifunctional 3D micro/nanosystems.

Creator

• Luan, Haiwen

DOI

• https://doi.org/10.21985/n2-2gfk-yq37

Subject

• Materials Science
• Mechanical engineering
• Civil engineering

Language

• en

Alternate Identifier

• http://dissertations.umi.com/northwestern:14682
• etdadmin_upload_663249

Date created

• 2019-01-01

Resource type

• Dissertation

Rights statement

• In Copyright