Microfluidic devices and methods for their preparation and use

Abstract

A microfluidic device is provided. The microfluidic device includes a microtube having a hollow core. The microfluidic device further includes a plurality of nanopores extending radially outwards from an inner surface of the microtube.

1 . A microfluidic device comprising:
 a microtube having a hollow core; and   a plurality of nanopores extending radially outwards from an inner surface of the microtube.   
     
     
         2 . The microfluidic device of  claim 1 , further comprising:
 first fluid that flows within the hollow core; and   a second fluid that flows over a nanoporous surface formed by the plurality of nanopores.   
     
     
         3 . The microfluidic device of  claim 2 , wherein the microfluidic device is configured to have the first fluid at a first temperature and the second fluid at a second temperature different than the first temperature and wherein the plurality of nanopores facilitate heat transfer between the first fluid and the second fluid. 
     
     
         4 . The microfluidic device of  claim 1 , wherein the microfluidic is formed of alumina (Al 2 O 3 ), titania (TiO 2 ), silicon (Si), silica (SiO 2 ), or combinations thereof. 
     
     
         5 . The microfluidic device of  claim 1 , wherein
 the microtube has an outer diameter of about 30 microns (μm) to about 300 μm;   the microtube has a wall thickness of about 10 μm to about 50 μm;   the hollow core has a diameter of about 1 μm to about 100 μm;   the plurality of nanopores have an average diameter of about 5 nanometers (nm) to about 150 nm; and   the plurality of nanopores have a wall thickness of about 5 nm to about 70 nm.   
     
     
         6 . The microfluidic device of  claim 1 , wherein the microtube further comprises a separation layer disposed proximate the inner surface of the microtube, wherein the plurality of nanopores terminate at the separation layer to prevent mixing of the first fluid and the second fluid. 
     
     
         7 . The microfluidic device of  claim 6 , wherein the separation layer is formed of a fluid-impermeable material. 
     
     
         8 . The microfluidic device of  claim 7 , wherein the separation layer is formed of alumina (Al 2 O 3 ), titania (TiO 2 ), silicon (Si) and silica (SiO 2 ), or combinations thereof. 
     
     
         9 . The microfluidic device of  claim 1 , wherein the plurality of nanopores have tapered diameter larger at the outer surface than towards the inner surface of the microtube. 
     
     
         10 . A heat exchanger comprising:
 a reservoir;   a plurality of microfluidic devices contained in the reservoir, wherein each of the plurality of microfluidic devices comprises: a microtube with a hollow core; and
 a plurality of nanopores extending radially outwards from an inner surface of the microtube. 
   
     
     
         11 . The heat exchanger of  claim 10 , further comprising:
 a first fluid contained in the reservoir, wherein the first fluid flows within the hollow core; and   a second fluid that flows over a nanoporous surface formed by the plurality of nanopores.   
     
     
         12 . The heat exchanger of  claim 11 , further comprising:
 an inlet configured to receive the second fluid; and   an outlet configured to discharge the second fluid.   
     
     
         13 . The heat exchanger of  claim 11 , wherein the microfluidic device is configured to have the first fluid at a first temperature and the second fluid at a second temperature different than the first temperature and wherein the plurality of nanopores of the microfluidic devices facilitate heat transfer between the first fluid and the second fluid. 
     
     
         14 . A method of transferring thermal energy, the method comprising:
 circulating a first fluid through a hollow core of a microtube;   circulating a second fluid over a plurality of nanopores extending radially outwards from an inner surface of the microtube; and   transferring the thermal energy between the first fluid and the second fluid that flows over a nanoporous surface formed by the plurality of nanopores of the microtube.   
     
     
         15 . The method of  claim 14 , wherein transferring the thermal energy comprises transferring the thermal energy between the first fluid at a first temperature and the second fluid at a second temperature different than the first temperature. 
     
     
         16 . The method of  claim 14 , wherein circulating the first fluid comprises circulating the first fluid through the microtube formed of alumina. 
     
     
         17 . A microfluidic device comprising:
 a microtube having a hollow core; and   a plurality of nanopores extending radially outwards from an inner surface of the microtube, wherein the diameter of each of the plurality of nanopores tapers linearly from the outer surface towards the inner surface of the microtube.   
     
     
         18 . The microfluidic device of  claim 17 , further comprising a first fluid that flows within the hollow core of the microtube. 
     
     
         19 . The microfluidic device of  claim 18 , wherein the plurality of nanopores are configured to introduce a reactant inside the hollow core of the microtube to facilitate mixing of the reactant and the first fluid. 
     
     
         20 . The microfluidic device of  claim 17 , wherein the microtube is formed of alumina. (Al 2 O 3 ), titania (TiO 2 ), silicon (Si), silica (SiO 2 ), or combinations thereof. 
     
     
         21 . The microfluidic device of  claim 17 , wherein
 the microtube has an outer diameter of about 30 microns (μm) to about 300 μm;   the microtube has a wall thickness about 10 μm to about 50 μm;   the hollow core has a diameter of about 1 μm to about 100 μm;   each of the plurality of nanopores has a diameter of about 5 nanometers (nm) to about 150 nm; and   each of the plurality of nanopores has a wall thickness of about 5 nm to about 70 nm.