This thesis explored the implementation of novel chemistries and processing techniques in 1-way and 2-way shape changing polymers. Shape memory polymers were developed from the copper catalyzed azide alkyne cycloaddition (CuAAC) as the polymerization reaction. These 1-way shape changing polymers used CuAAC as the polymerization reaction that led to a very narrow glass transition, readily tunable properties, and very high shape fixity (99%) and recovery (99%). In addition, folding was implemented as a programming methodology in ductile, glassy polymer networks, which were folded by hand then unfolded after heating through the glass transition. Multiple three-dimensional temporary shapes, such as a swan, airplane, and fortuneteller, were formed from the same sheet of polymer by erasing the folds after each step thereby resetting the polymer sheet. Ductility in certain polymer networks enabled this behavior. These novel chemistries and processing approaches simplify the programming and chemical design of functional shape changing materials.

This thesis further describes the development and implementation of addition fragmentation chain transfer (AFT) in liquid crystalline networks (LCNs) as a means for precise, reversible control of shape change and acutation. AFT decoupled the bond exchange reaction from the thermotropic liquid crystalline behavior leading to spatiotemporal control over the LCN alignment and domain structure. The response and manifestation of the bond exchange was dependent on the geometry and alignment. As such, three geometries were employed including: confined cells, surface coatings, and freely standing films. In confined cells, AFT disrupted the alignment programmed prepolymerization by using to light to induce AFT while simultaneously heating close to or above the phase transition temperature. In this manner, bond exchange, initiated at any temperature, caused the network to approach the thermodynamic equilibrium at the given temperature enabling tuning of the domain structure and birefringence by selecting the appropriate temperature. On surfaces, disruption induced by photopatterned AFT led to an increase in the thickness of exposed regions of a planarly aligned coating. Because light is the stimulus, patterned disruption caused surface topography to form when AFT was initiated in the isotropic phase. In freely standing LCN films, AFT provided a mechanism to efficiently and effectively program shape changes. Arising from the decoupled bond exchange and thermotropic phase behavior, programming in the LC phase did not significantly change the isotropic shape. AFT enabled remolding of the isotropic shape when initiated in the isotropic phase, and when done without any applied strain, AFT bond exchange stochastically reorganizes the network to effectively erase all programming. Programming and erasing were done over multiple cycles and found to be repeatable as long as photoinitiator was present.

Using this fundamental knowledge, this thesis explored multiple demonstrations of the versatility and limitations of AFT-capable LCNs. Complex shape changes such as transitioning from one folded object to another folded object, or from one bulk shape to another, twisted to untwisted, and nanoscale surface patterns were programmed into AFT-capable LCNs. In total, this thesis described the development of a highly versatile and programmable shape changing material with the ability to have independent control over the shapes and switching temperature. Three Supplemental videos have also been uploaded with this thesis. Video 4.S1 shows the unfolding of a origami spring pushing up a 1 gram weight when heated. Video 5.S1 shows the complete erasing of birefringence when the light turns on. Video 6.S1 shows the folding and unfolding during thermal cycling of a liquid crystalline elastomer miura fold programmed with light.