Environmental and Economic Sustainability of Stereolithography-based 4D Printing

Additive manufacturing (AM), also known as 3D printing, has gained wide acceptance as a versatile technique for complex structure fabrication. 4D printing of stimuli-responsive materials extends 3D printing by enabling the fabricated structures with abilities to transform their shapes and properties over time in response to external stimuli. Numerous research efforts have been dedicated to enhancing material printability and ensuring time-evolving properties, indicating potential applications in healthcare, automotive, and aerospace. As a newly emerged technology, 4D printing presents the possibilities of emergent environmental and economic impacts due to the use of unconventional materials and stimuli-response mechanisms along the added time dimension. The associations between the new material-process-property characteristics and critical sustainability metrics in 4D printing have not yet been well-assessed in the current literature. To advance the state-of-the-art on the environmental and economic sustainability of 4D printing, this Ph.D. dissertation is conducted to (1) establish theoretical models for critical environmental measures such as energy consumption and process emissions; (2) investigate the key factors influencing energy efficiency and cost allocations, as well as the formation mechanisms of process emissions; (3) develop sustainability-conscious process planning approaches for reducing environmental burden and increasing economic value in the adoption of 4D printing technologies; and (4) explore novel applications of 4D printing that align with sustainability objectives. The outcomes of this dissertation will facilitate the sustainability-aware process-planning towards reduced environmental burden and increased economic value in adopting 4D printing.