Flexible microreactors integrating lattice micromixers for water purification

초록

Flexible photocatalytic microreactors are attractive for field deployable water purification, yet conventional designs rely on rigid substrates and suffer transport limitations under deformation and finite residence times. Here, a mechanically compliant optofluidic microreactor is introduced that integrates TiO₂ coated architected lattice micromixers within a soft polydimethylsiloxane (PDMS) chamber, providing an immobilized catalytic interface and mixing enhanced transport. Lattice topology and strut geometry were systematically investigated through purification experiments, transport simulations, and mechanical tests. The results show that purification is governed not simply by catalytic surface area, but by architecture-induced flow perturbation, cross-sectional mixing, and interfacial transport renewal. Among the tested structures, the body-centered cubic (BCC) lattice exhibited the best performance, achieving up to 99.4% methylene blue (MB) removal under continuous-flow operation. Apparent reaction kinetics exhibited a non-monotonic dependence on residence time, revealing an over-residence regime at very low flow rates where weak convective replenishment limited turnover. Numerical simulations mechanistically supported these findings by showing that the BCC geometry provides a favorable balance between flow penetration and hydraulic resistance. Mechanical tests show rod interconnected networks dominate compliance, sustaining ~29% tensile strain and remaining intact under tight mandrel bending. Practical translation is demonstrated by a 4 × 4 scaled array achieving removal efficiency (96.9%) under natural sunlight and a compact, closed loop circulation system reaching removal efficiency (96.6%) of MB within 8 h at 47 mL·min−1. These results demonstrate that architected lattice design provides an effective strategy for simultaneously achieving transport-efficient purification, mechanical compliance, and practical scalability in flexible photocatalytic microreactors. © 2026 Elsevier B.V.

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