Surfactants with a terminal dialkyl- or cycloalkyl-substituted tertiary amine and inks including the same

Abstract

Surfactants are provided that have a hydrophobic tail portion and a hydrophilic head portion. The hydrophilic head portion includes a terminal dialkyl-substituted tertiary amine or a terminal cycloalkyl-substituted tertiary amine. Also provided are pigment-based inks employing the surfactant, a combination of an electronic display and the pigment-based inks, and a process for reducing conductivity in primary amine-based surfactants and improving reliability of electronic inks employing such surfactants.

What is claimed is: 
     
         1 . A surfactant having a hydrophobic tail portion and a hydrophilic head portion, the hydrophilic head portion including a terminal dialkyl-substituted tertiary amine or a terminal cycloalkyl-substituted tertiary amine, and the hydrophobic tail portion including a polyisobutylene chain. 
     
     
         2 . The surfactant of  claim 1 , wherein the hydrophilic head portion is selected from the group consisting of dialkyl-substituted polyaliphatic amines, cycloalkyl-substituted polyaliphatic amines, dialkyl tertiary amine-terminated polyethylene glycols, cycloalkyl tertiary amine-terminated polyethylene glycols, dialkyl tertiary amine-terminated alkanes, and cycloalkyl tertiary amine-terminated alkanes. 
     
     
         3 . The surfactant of  claim 1 , wherein the surfactant has the structure: 
       
         
           
           
               
               
           
         
       
       wherein
 the letters R1 to R2 each independently represent an optionally substituted alkyl, alkenyl, aryl or aralkyl groups; and 
 the letter n is an integer from 5 to 500. 
 
     
     
         4 . A pigment-based ink, including:
 a non-polar carrier fluid;   a pigment; and   the surfactant of  claim 1 .   
     
     
         5 . The ink of  claim 4 , wherein the non-polar carrier fluid is a non-polar solvent selected from the group consisting of hydrocarbons, halogenated hydrocarbons, partially halogenated hydrocarbons, and siloxanes. 
     
     
         6 . The ink of  claim 4 , wherein the pigment is selected from the group consisting of black pigments, yellow pigments, magenta pigments, red pigments, violet pigments, cyan pigments, blue pigments, green pigments, orange pigments, brown pigments, and white pigments. 
     
     
         7 . A pigment-based ink, including:
 a non-polar carrier fluid;   a pigment; and   the surfactant of  claim 3 .   
     
     
         8 . The ink of  claim 7 , wherein the non-polar carrier fluid is a non-polar solvent selected from the group consisting of hydrocarbons, halogenated hydrocarbons, partially halogenated hydrocarbons, and siloxanes. 
     
     
         9 . The ink of  claim 7 , wherein the pigment is selected from the group consisting of black pigments, yellow pigments, magenta pigments, red pigments, violet pigments, cyan pigments, blue pigments, green pigments, orange pigments, brown pigments, and white pigments. 
     
     
         10 . In combination, an electronic display and an electronic ink, wherein the electronic display includes:
 a first electrode;   a second electrode; and   a display cell having a recess defined by a dielectric material, the first electrode, and the second electrode, the display cell containing the electronic ink; and wherein the electronic ink includes:
 a non-polar carrier fluid; 
 a pigment; and 
 the surfactant of  claim 1 . 
   
     
     
         11 . The combination of  claim 10 , wherein the electronic display includes a plurality of display cells in a stacked configuration, associated first electrodes and second electrodes, and a plurality of electronic inks of different colors, each display cell containing an electronic ink of a different color. 
     
     
         12 . The combination of  claim 10 , wherein the non-polar carrier fluid is a non-polar solvent selected from the group consisting of hydrocarbons, halogenated hydrocarbons, partially halogenated hydrocarbons, and siloxanes. 
     
     
         13 . The combination of  claim 11 , wherein the colored pigment is a colored polymeric particle having a size ranging from 1 nm to 10 μm and is selected from the group consisting of black pigment particles, yellow pigment particles, magenta pigment particles, red pigment particles, violet pigment particles, cyan pigment particles, blue pigment particles, green pigment particles, orange pigment particles, brown pigment particles, and white pigment particles. 
     
     
         14 . The combination of  claim 10 , wherein the surfactants have a hydrophobic tail and a hydrophilic head and are selected from the group consisting of dialkyl-substituted and cycloalkyl-substituted polyaliphatic amines, dialkyl and cycloalkyl tertiary amine-terminated polyethylene glycols, and dialkyl and cycloalkyl tertiary amine-terminated alkanes, the surfactants having polyisobutylene chains as the hydrophobic tail and the polyaliphatic amines having dialkyl or cycloalkyl substituted polyaliphatic amines as the hydrophilic head, or the polyethylene glycol amines having dialkyl or cycloalkyl tertiary amine-terminated polyethylene glycols as the hydrophilic head, or the alkane amines having dialkyl or cycloalkyl tertiary amine-terminated alkanes as the hydrophilic head. 
     
     
         15 . A method for reducing conductivity in primary amine-based surfactants and improving reliability of electronic inks employing such surfactants, the method comprising replacing a terminal primary amine group on the surfactants with a dialkyl-substituted tertiary amine or a cycloalkyl-substituted tertiary amine.