Method and apparatus for controlling the movement of a liquid on a nanostructured or microstructured surface

Abstract

A method and apparatus is disclosed wherein the movement of a droplet disposed on a nanostructured or microstructured surface is determined by at least one characteristic of the nanostructure feature pattern or at least one characteristic of the droplet. In one embodiment, the movement of the droplet is laterally determined by at least one characteristic of the nanostructure feature pattern such that the droplet moves in a desired direction along a nanostructured feature pattern. In another embodiment, the movement of the droplet is determined by either at least one characteristic of the nanostructure feature pattern or at least one characteristic of the droplet in a way such that the droplet penetrates the feature pattern at a desired area and becomes substantially immobile.

What is claimed is:  
     
         1 . An apparatus comprising a surface having a pattern of features, said surface comprising: 
 a plurality of nanostructures or microstructures having intra-pattern characteristics, at least one of said intra-pattern characteristics adapted to produce controlled motion in a predetermined direction of a droplet of liquid disposed on said surface.    
     
     
         2 . The apparatus of  claim 1  wherein said at least one of said intra- pattern characteristics is a voltage of at least one of said nanostructures or microstructures relative to said droplet.  
     
     
         3 . The apparatus of  claim 1  wherein said at least one said intra-pattern characteristics is a distance between each of at least a portion of said plurality of nanostructures or microstructures.  
     
     
         4 . The apparatus of  claim 1  wherein said at least one of said intra- pattern characteristics is a shape of at least a portion of said plurality of nanostructures or microstructures.  
     
     
         5 . An apparatus comprising: 
 a surface having a pattern of nanostructures or microstructures, the spatial density of at least a portion of said pattern of nanostructures or microstructures being varied; and    a droplet of liquid disposed on said surface;    wherein the spatial density of said pattern is adapted to produce controlled motion of said droplet in a predetermined direction.    
     
     
         6 . An apparatus comprising: 
 a surface having a pattern of nanostructures or microstructures, the spatial density of at least a portion of said pattern of nanostructures or microstructures being varied; and    a droplet of liquid disposed on said surface;    wherein the area of contact between said surface and said droplet is adapted to produce controlled motion of said droplet in a predetermined direction.    
     
     
         7 . An apparatus comprising: 
 a surface having a pattern of nanostructures or microstructures;    a droplet of liquid disposed on said surface; and    means for causing said droplet to penetrate said surface.    
     
     
         8 . The apparatus of  claim 7  wherein said means for causing comprises means for applying a voltage to said droplet.  
     
     
         9 . The apparatus of  claim 7  wherein said means for causing comprises means for reducing a surface tension of said droplet.  
     
     
         10 . The apparatus of  claim 9  wherein said means for reducing comprises means for introducing at least a chemical or biological element into at least a portion of said droplet.  
     
     
         11 . The apparatus of  claim 7  wherein at least a portion of a beam of light incident upon said surface passes through said surface, said portion depending upon whether said droplet is penetrated into said surface.  
     
     
         12 . The apparatus of  claim 7  wherein at least a portion of a beam of light incident upon said surface is reflected off of said surface, said portion depending upon whether said droplet is penetrated into said surface.  
     
     
         13 . The apparatus of  claim 7  wherein a first wavelength of a beam of light is reflected off of said surface in a first predetermined direction.  
     
     
         14 . The apparatus of  claim 13  wherein, upon said droplet of liquid penetrating said pattern, a second wavelength of light is reflected off of said surface in a second predetermined direction.  
     
     
         15 . The apparatus of  claim 7  wherein said means for causing comprises means for increasing the temperature of said droplet of liquid.  
     
     
         16 . The apparatus of  claim 7  wherein said means for causing comprises means for increasing the temperature of said surface.  
     
     
         17 . An apparatus comprising a surface, said surface adapted to produce controlled motion of a droplet of liquid in a predetermined direction, said droplet disposed on said surface, said surface comprising a plurality of nanostructures or microstructures, wherein at least a first portion of said plurality has a different spatial density from at least a second portion of said plurality.  
     
     
         18 . An apparatus comprising a surface, said surface adapted to produce controlled motion of a droplet of liquid in a predetermined direction, said droplet disposed on said surface, said surface comprising a plurality of nanostructures or microstructures, wherein each of the nanostructures or microstructures in at least a first portion of said plurality has a predetermined asymmetric shape.  
     
     
         19 . The apparatus of  claim 18  wherein each of the nanostructures or microstructures in at least a second portion of said plurality has a varied spatial density.  
     
     
         20 . A method for detecting the presence of a chemical or biological element with a detector, said detector having a surface, said surface comprising a pattern of nanostructures or microstructures and a droplet of a liquid disposed on said surface, said method comprising the step of exposing said detector to a medium, 
 wherein said liquid has been selected in a way such that said droplet penetrates said surface in response to a chemical or biological element in said medium being introduced into said droplet.    
     
     
         21 . The method of  claim 20  further comprising generating an indication in response to said droplet penetrating said surface.  
     
     
         22 . The method of  claim 21  wherein said indication comprises a change in the color of at least a portion of said surface.  
     
     
         23 . The method of  claim 21  wherein said indication comprises an electrical signal.  
     
     
         24 . A microfluidic mixer comprising: 
 a first channel adapted to accommodate a first liquid;    a second channel adapted to accommodate a second liquid;    a third channel adapted to accommodate a third liquid,    wherein said third liquid comprises said first liquid and said second liquid;    means for merging said first channel and said second channel into said third channel; and    means for disturbing a flow in said third channel by causing at least one of said first liquid and said second liquid to penetrate a surface of said third channel.    
     
     
         25 . A tunable heat dissipation device comprising: 
 a channel adapted to accommodate a liquid    wherein a heat generating apparatus is disposed on a surface of said channel; and    means for disturbing a flow in said channel by causing said liquid to penetrate a surface of said channel.