Inks including segment copolymer grafted pigments via azide chemistry

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;
• and
• a surface-functionalized pigment particle including a nitrogen-linked moiety to the surface of the pigment particle through a nitrogen link at one end of the nitrogen-linked moiety and a segment copolymer having at least two blocks attached at another end, wherein the segment copolymer has a formula selected from the group consisting of segment copolymer 1, segment copolymer 2, and segment copolymer 3, as shown below:
• wherein,
• L1, L2, and L3 are each independently a covalent bond or chemical structure providing a covalent bond between different blocks selected from the group consisting of C—C, C═C, C═N, C≡C, and N≡N;
• SG1 and SG2 each independently represent a solubilizing and sterically bulky group, which helps to improve the solubility of the polymer and stabilize the colorant particles, selected from the group consisting of alkyl groups, alkoxy groups, branched alkyl groups, branched alkoxy groups, aliphatic esters, branched aliphatic esters, substituted phenyl groups, and macromolecular monomers;
• FG represents a functional group that provides charging sites to pigment surfaces, selected from acidic functional groups and basic groups;
• x, y and z are each independently an integer between 1 and about 5,000;
• and n is an integer between 2 and about 100,
• wherein the pigment particle is suspended in the non-polar carrier fluid.

A method for making a nitrogen-linked surface functionalized pigment particle including:

• providing an azide;
• causing the azide to initiate polymerization of a first block monomer to give a first block azide living polymer;
• adding a second monomer to the first block living polymer to give a two-block azide living copolymer and form a first segment;
• forming at least one additional segment by adding, in any order, a first block monomer and a second block monomer to form a two-block living segment copolymer;
• wherein the segment copolymer has a formula selected from the group consisting of segment copolymer 1, segment copolymer 2, and segment copolymer 3, as shown below:
• wherein,
• L1, L2, and L3 are each independently a covalent bond or chemical structure providing a covalent bond between different blocks selected from the group consisting of C—C, C═C, C═N, C≡C, and N≡N;
• SG1 and SG2 each independently represent a solubilizing and sterically bulky group, which helps to improve the solubility of the polymer and stabilize the colorant particles, selected from the group consisting of alkyl groups, alkoxy groups, branched alkyl groups, branched alkoxy groups, aliphatic esters, branched aliphatic esters, substituted phenyl groups, and macromolecular monomers;
• FG represents a functional group that provides charging sites to pigment surfaces, selected from acidic functional groups and basic groups;
• x, y and z are each independently an integer between 1 and about 5,000;
• and n is an integer between 2 and about 100, and
• causing an inorganic or organic pigment particle to undergo a coupling reaction with the azide on the two-block living segment copolymer to form a functionalized di-block segment copolymer coupled to the pigment particle through a nitrogen link.