Scientists and engineers will create the next generation of materials by precisely controlling their microstructure. One of the most promising and effective methods to control material microstructure is self-assembly, in which the properties of constituent “particles” guide their assembly into the desired structure. Self-assembly mechanisms rely on both inherent interactions between particles and emergent interactions resulting from the collective effects of all particles in the system. These emergent effects are of interest as they provide minimal mechanisms to control self-assembly, and thus can be used in conjunction with other assembly methods to create novel materials

Literature shows that complex phases can be obtained solely from hard, anisotropic particles, which are attracted via an emergent Directional Entropic Force. This thesis shows that this force gives rise to the entropic bond, a mesoscale analog to the chemical bond. Entropic bonds are quantified, and their ability to be manipulated to produce similar self-assembly behavior to chemically-functionalized nanoparticles is demonstrated. Further investigation shows their ability to alter self-assembled structures, as well as the phase behavior of nanoparticle systems. With greater understanding of entropic bonds, we can create and control continuous mesoscale bonds, opening new avenues for investigation into self-assembly and reconfigurable materials.

DISSERTATION COMMITTEE

Co-Chairs:
Prof. Sharon Glotzer, ChE/MSE
Asst. Prof. Greg, van Anders, Physics
Members:
Prof. John Kieffer, MSE
Cognate:
Prof. Michael Solomon, ChE