Variable charge films for controlling microfluidic flow
First Claim
1. A microfluidic device for carrying a liquid, the device comprising a microfluidic channel having an interior wall and a polyelectrolyte film on the interior wall whereby liquid carried by the channel contacts the polyelectrolyte film, the polyelectrolyte film having a thickness of about 1 to about 1000 nanometers and comprising an interpenetrating network of a predominately positively charged polymer and a predominately negatively charged polymer, wherein the predominately positively charged polymer, the predominately negatively charged polymer or both is a copolymer, the copolymer comprising both (i) a pH insensitive positively or negatively charged repeat unit having a pKa greater than 9 or less than 3, and (ii) a pH sensitive repeat unit, the pH sensitive repeat unit having a pKa of 3 to 9, whereby the pH of liquid in the microfluidic channel may be used to control the velocity or direction of electroosmotic flow of the liquid within said microfluidic channel.
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Abstract
A microfluidic device for carrying a liquid, the device comprising a microfluidic channel having an interior wall and a polyelectrolyte film on the interior wall whereby liquid carried by the channel contacts the polyelectrolyte film, the polyelectrolyte film having a thickness of about 1 to about 1000 nanometers and comprising an interpenetrating network of a predominantly positively charged polymer and a predominantly negatively charged polymer, the predominantly positively charged polymer, the predominantly negatively charged polymer or both containing (i) a pH insensitive positively or negatively charged repeat unit having a pKa greater than 9 or less than 3, and (ii) a pH sensitive repeat unit, the pH sensitive repeat unit having a pKa of 3 to 9, whereby the pH of liquid in the microfluidic channel may be used to control the velocity or direction of electroosmotic flow of the liquid within said microfluidic channel.
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Citations
27 Claims
- 1. A microfluidic device for carrying a liquid, the device comprising a microfluidic channel having an interior wall and a polyelectrolyte film on the interior wall whereby liquid carried by the channel contacts the polyelectrolyte film, the polyelectrolyte film having a thickness of about 1 to about 1000 nanometers and comprising an interpenetrating network of a predominately positively charged polymer and a predominately negatively charged polymer, wherein the predominately positively charged polymer, the predominately negatively charged polymer or both is a copolymer, the copolymer comprising both (i) a pH insensitive positively or negatively charged repeat unit having a pKa greater than 9 or less than 3, and (ii) a pH sensitive repeat unit, the pH sensitive repeat unit having a pKa of 3 to 9, whereby the pH of liquid in the microfluidic channel may be used to control the velocity or direction of electroosmotic flow of the liquid within said microfluidic channel.
- 20. A process of derivatizing the surface of a microfluidic channel, the process comprising alternately passing solutions comprising positively charged and negatively charged polyelectrolytes through the microfluidic channel to form a polyelectrolyte film on the inner surface of the channel, the film having a thickness between about 1 and about 1000 nanometers and comprising an interpenetrating network of a predominately positively charged polymer and a predominately negatively charged polymer, wherein the predominately positively charged polymer, the predominately negatively charged polymer or both is a copolymer, the copolymer comprising both (i) a pH insensitive positively or negatively charged repeat unit having a pKa greater than 9 or less than 3, and (ii) a pH sensitive repeat unit, the pH sensitive repeat unit having a pKa between 3 and 9 and complex in contact with the interior surface of a microfluidic channel whereby the pH of liquid in the microfluidic channel may be used to control the velocity or direction of electroosmotic flow of the liquid within said microfluidic channel.
- 23. A process of controlling the flow of liquid in a microfluidic channel, the process comprising changing the pH of liquid in the microfluidic channel to change the velocity or direction of flow of the liquid in the channel, wherein the microfluidic channel has an interior wall and a polyelectrolyte film on the interior wall whereby liquid carried by the channel contacts the polyelectrolyte film, and the polyelectrolyte film has a thickness between about 1 and about 1000 nanometers and comprises an interpenetrating network of a predominately positively charged polymer and a predominately negatively charged polymer, wherein the predominately positively charged polymer, the predominately negatively charged polymer or both is a copolymer, the copolymer comprising both (i) a pH insensitive positively or negatively charged repeat unit having a pKa greater than 9 or less than 3, and (ii) a pH sensitive repeat unit, the pH sensitive repeat unit having a pKa of about 3 to 9.
Specification