Progressive colloidal clogging via dendrite growth in porous media

The transport of colloidal particles in porous media governs deposition and clogging mechanisms that significantly impact flow efficiency in both natural and engineered systems. Yet, the contribution of dendritic structures—a unique deposition morphology—to clogging dynamics is still poorly explored. Understanding the formation and growth of dendrites is essential for advancing clogging dynamics and assessing their impact on permeability. Using microfluidic flow experiments coupled with computational fluid dynamics, we investigate this dendrite-based clogging mechanism in a heterogeneous, tortuous porous domain. Our results reveal a novel clogging mechanism—dendrite clogging—where a single deposition site initiates a structure that extends across the pore space, bridging grains and causing complete clogging. Unlike previously described aggregation-based clogging, which involves multiple deposition sites, dendrite clogging evolves from a single-site deposition. Through hydrodynamic and adhesive torque balance analysis, we develop a flow-dependent criterion that predicts dendrite formation. Our results demonstrate that moderate flow rates favor multilayer deposition in front-cone stagnation zones, triggering dendrite growth and abrupt permeability loss. In contrast, higher flow rates suppress dendrite formation, resulting in more gradual permeability decline, well described by the Verma–Pruess permeability-porosity model. These insights establish a predictive framework for dendritic deposition under different flow conditions. They also shed light on previously unexplored clogging mechanisms, contributing to a deeper understanding of clogging in porous media with implications on optimizing flow in systems such as filtration, groundwater transport, and biomedical microfluidics.