Abstract:Therapeutically reconstructing hard tissues such as dental enamel, bone, or cartilage via material infiltration is highly desirable for medical applications. However, the nanoporous structure of hard tissue renders infiltration inherently challenging and techniques have relied on passive diffusion, limiting their effects mainly to the surface area. Recent innovations in material infiltration utilizing electrokinetic transport capable of deep (≈1 mm) infiltration have been introduced. Despite the potential of e… Show more
Overlimiting current (OLC) is a non-linear current response that occurs related to an ion concentration polarization (ICP) phenomenon in micro/nanofluidic systems and holds great importance since it represents the rate of selective ion transportation through perm-selective structure. For last two decades, numerous studies of OLC have been reported about understanding the fundamentals of nanoelectrokinetics and enhancing ion transportation through perm-selective membranes. Recent study reported that the alignment of non-uniform microspace near the perm-selective membranes in two-dimensional micro/nanofluidic systems can significantly enhance OLC, i.e., overlimiting conductance (σOLC). This is attributed to recirculation flow induced by combination of unbalanced electroosmosis and induced pressure driven flow among non-uniform microspaces. However, 2D micro/nanofluidic systems have limited practicality due to their small volume and low throughput. Herein, we tested the OLC enhancement using 3D-printed hierarchical micro/nanofluidic systems with respect to the non-uniformity of microspaces. The 3D microspaces were fabricated as a mesh structure using a conventional 3D printer. By comparing current–voltage measurement with each type of mesh, we experimentally confirmed the generation of recirculation flow among non-uniform meshes and ionic current enhancement in 3D hierarchical micro/nanofluidic system. Also, we further investigated the enhancement of overlimiting conductance depending on the mesh pattern. Furthermore, we validated that this effect of microscale non-uniform compartmentalization, both increasing surface area and aligning non-uniform spaces, appears not only at low molar concentration but at high molar concentrations. This demonstration can offer a strategy to design optimal electrochemical systems where a perm-selective ion transportation is crucial.
Overlimiting current (OLC) is a non-linear current response that occurs related to an ion concentration polarization (ICP) phenomenon in micro/nanofluidic systems and holds great importance since it represents the rate of selective ion transportation through perm-selective structure. For last two decades, numerous studies of OLC have been reported about understanding the fundamentals of nanoelectrokinetics and enhancing ion transportation through perm-selective membranes. Recent study reported that the alignment of non-uniform microspace near the perm-selective membranes in two-dimensional micro/nanofluidic systems can significantly enhance OLC, i.e., overlimiting conductance (σOLC). This is attributed to recirculation flow induced by combination of unbalanced electroosmosis and induced pressure driven flow among non-uniform microspaces. However, 2D micro/nanofluidic systems have limited practicality due to their small volume and low throughput. Herein, we tested the OLC enhancement using 3D-printed hierarchical micro/nanofluidic systems with respect to the non-uniformity of microspaces. The 3D microspaces were fabricated as a mesh structure using a conventional 3D printer. By comparing current–voltage measurement with each type of mesh, we experimentally confirmed the generation of recirculation flow among non-uniform meshes and ionic current enhancement in 3D hierarchical micro/nanofluidic system. Also, we further investigated the enhancement of overlimiting conductance depending on the mesh pattern. Furthermore, we validated that this effect of microscale non-uniform compartmentalization, both increasing surface area and aligning non-uniform spaces, appears not only at low molar concentration but at high molar concentrations. This demonstration can offer a strategy to design optimal electrochemical systems where a perm-selective ion transportation is crucial.
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