Efficient network-matrix architecture for general flow transport inspired by natural pinnate leaves

Temperature - dependent polymer absorber as a switchable state NIR reactor

This research studies a lower down transition temperature composite polymer, modulated by multi microchannel fluidic flows to advance a thermally controllable material. Through modulating volumetric flow rates to manipulate fluid-material interface for heat transport within a microfluidic platform. Determining this optimization at any given flow rate will advance fluidics acting as a filter for invisible irradiation, near IR (NIR) range of the electromagnetic spectrum. In principle, filtering out this part of the solar irradiation spectrum can be achieved by selective fluidic absorption. By switchable control of conductance states to make the material switch on for high conductance or switch off for low conductance as a heat seeking targeting material. The challenges in material science is our ability to evaluate heat flow and monitor temperature with time. This research will determine the use of microfluidics based flows to direct the structural assembly of a polymer into a thermal switch. The research is inspired by nature's vasculature leaf formations to modulate irradiance absorption by laminar fluidic flow. This bio-inspired engineering approach advances the structural assembly of polymers. By finely tuning flows to manipulate thermal gains in microchannel network architecture through flow rate switching to define composite function in differing conductance states. The research determines control of the thermodynamic state of a composite is directed by planar extensional flow in a microfluidic platform for high cooling surfaces.

Design and characterization of hydrogel-based microfluidic devices with biomimetic solute transport networks

Hydrogel could serve as a matrix material of new classes of solar cells and photoreactors with embedded microfluidic networks. These devices mimic the structure and function of plant leaves, which are a natural soft matter based microfluidic system. These unusual microfluidic-hydrogel devices with fluid-penetrable medium operate on the basis of convective-diffusive mechanism, where the liquid is transported between the non-connected channels via molecular permeation through the hydrogel. We define three key designs of such hydrogel devices, having linear, T-shaped, and branched channels and report results of numerical simulation of the process of their infusion with solute carried by the incoming fluid. The computational procedure takes into account both pressure-driven convection and concentration gradient-driven diffusion in the permeable gel matrix. We define the criteria for evaluation of the fluid infusion rate, uniformity, solute loss by outflow and overall performance. The T-shaped channel network was identified as the most efficient one and was improved further by investigating the effect of the channel-end secondary branches. Our parallel experimental data on the pattern of solute infusions are in excellent agreement with the simulation. These network designs can be applied to a broad range of novel microfluidic materials and soft matter devices with distributed microchannel networks.

Plant leaves as templates for soft lithography

Complex microvascular venation patterns of natural leaves are replicated into PDMS replicas, which allows for a leakage-tight seal with a flat substrate despite the surface topography.