Water diffusion in additively manufactured polymers: effect of capillary shapes

Additive manufacturing (AM) is an advanced manufacturing technique that produces objects through sequential layering. However, defects generated during such manufacturing lead to a complex internal structure in 3D-printed polymers, resulting in unique micro-mechanisms governing water diffusion. The effects of exposure to water on the mechanical properties of AM materials remain insufficiently understood. Recent studies acknowledged the impact of capillary flow penetrating the polymer; however, most of this research is performed at the macroscale. This study aims to explore the effect of capillary shape on the speed and range of the capillary flow. A constitutive model, derived from the previous numerical studies, is adapted to various capillary geometries. It is demonstrated that the shape significantly affects the penetration speed and distance of capillary flow.