Composite electrophoretic particles having polymer shells including first and second monomeric units

Abstract

An electrophoretic medium includes a fluid, a plurality of light scattering charged particles having a first polarity, and a first, second, and third set of particles, each set having a color different from each other set. The first and second particles may have a second polarity opposite to the first polarity, and the mobility of the third set of particles is less than half of the mobility of the light scattering particles, the first set of charged particles, and the second set of charged particles.

1 . A composite electrophoretic particle, comprising:
 a core pigment; and   a polymer shell,   wherein:   
       (a) a mass fraction of the polymer shell to the composite particle (core pigment+polymer shell) is at least 20 wt % to at most 50 wt %; and 
       (b) the polymer shell comprises: 
       (I) a first monomeric unit derived from a first precursor of Formula (1):
   CH 2 ═C(R 1a )C(O)R 2   (2)
 
 
       wherein: R 1a  is —H or —CH 3 ; R 2  is —OR 3 , —NHR 3 , or —NR 3   2 ; R 3  is C 1-6  alkyl, C 1-6  heteroalkyl, C 3-10  cycloalkyl, C 3-10  heterocycloalkyl, C 6-14  aryl, C 5-14  heteroaryl, or any combination thereof, each of which is optionally substituted one more times by groups selected independently from R 4 ; 
       R 4  is a C 1-6  alkyl, —OH, C 1-6  alkoxy, —NH 2 , —NH(C 1-6  alkyl), —N(C 1-6  alkyl) 2 , C 1-6  haloalkyl, or C 1-6  haloalkoxy; and 
       (II) a second monomeric unit derived from a second precursor of Formula (2):
   CH 2 ═C(R 1b )C(O)R 5   (2)
 
 
       wherein: R 1b  is —H or —CH 3 ; R 5  is —OR 6 , —NHR 6 , or —NR 6   2 ; R 6  is C 1-6  alkyl, C 1-6  heteroalkyl, C 3-10  cycloalkyl, C 3-10  heterocycloalkyl, C 6-14  aryl, C 5-14  heteroaryl, or any combination thereof, each of which is substituted one or more times by groups selected independently from R 7 ; R 7  is a halogen, —CN, —NO 2 , —S(O)—, or —S(O) 2 —. 
     
     
         2 . The composite electrophoretic particle of  claim 1 , wherein R 3  is C 1-6  alkyl, C 6-14  aryl, or any combination thereof, each of which is optionally substituted one or more times by groups selected independently from R 4 ; and R 4  is a C 1-6  alkyl, or C 1-6  alkoxy. 
     
     
         3 . The composite electrophoretic particle of  claim 1 , wherein R 2  is —OR 3 , and R 3  is C 1-6  alkyl or C 6-14  aryl, the C 6-14  aryl optionally substituted one or more times by groups selected independently from R 4 ; and R 4  is C 1-6  alkoxy. 
     
     
         4 . The composite electrophoretic particle of  claim 1 , wherein R 6  is C 1-6  alkyl and R 7  is a halogen. 
     
     
         5 . The composite electrophoretic particle of  claim 1 , wherein R 5  is —OR 6 , R 6  is C 1-6  alkyl substituted at least three times by R 7 , and R 7  is —F. 
     
     
         6 . The composite electrophoretic particle of  claim 1 , wherein the first precursor is selected from the group consisting of methyl methacrylate, methoxyphenyl methacrylate, and N,N-di-isopropylacrylamide. 
     
     
         7 . The composite electrophoretic particle of  claim 1 , wherein the second precursor is trifluoroethyl methacrylate (TFEM). 
     
     
         8 . The composite electrophoretic particle of  claim 1 , wherein the mass fraction of the polymer shell to the composite particle is measured by thermogravimetric analysis (TGA). 
     
     
         9 . A composite electrophoretic particle, comprising:
 a core pigment; and   a polymer shell,   wherein:   
       (a) a mass fraction of the polymer shell to the composite particle (core pigment+polymer shell) is at least 20 wt % to at most 50 wt %; and 
       (b) the polymer shell comprises: 
       (I) a first monomeric unit derived from a first precursor of Formula (1):
   CH 2 ═C(R 1a )C(O)R 2   (2)
 
 
       wherein: R 1a  is —H or —CH 3 ; R 2  is —OR 3 , —NHR 3 , or —NR 3   2 ; R 3  is C 1-6  alkyl, C 1-6  heteroalkyl, C 3-10  cycloalkyl, C 3-10  heterocycloalkyl, C 6-14  aryl, C 5-14  heteroaryl, or any combination thereof, each of which is optionally substituted one more times by groups selected independently from R 4 ; 
       R 4  is a C 1-6  alkyl, —OH, C 1-6  alkoxy, —NH 2 , —NH(C 1-6  alkyl), —N(C 1-6  alkyl) 2 , C 1-6  haloalkyl, or C 1-6  haloalkoxy; and 
       (II) a second monomeric unit derived from a styrene optionally substituted one or more times by groups selected independently from C 1-6  alkyl, C 1-6  alkoxy, —NH(C 1-6  alkyl), —N(C 1-6  alkyl) 2 , and halogen. 
     
     
         10 . The composite electrophoretic particle of  claim 9 , wherein R 3  is C 1-6  alkyl, C 6-14  aryl, or any combination thereof, each of which is optionally substituted one or more times by groups selected independently from R 4 ; and R 4  is a C 1-6  alkyl, or C 1-6  alkoxy. 
     
     
         11 . The composite electrophoretic particle of  claim 9 , wherein R 2  is —OR 3 , and R 3  is C 1-6  alkyl or C 6-14  aryl, the C 6-14  aryl optionally substituted one or more times by groups selected independently from R 4 ; and R 4  is C 1-6  alkoxy. 
     
     
         12 . The composite electrophoretic particle of  claim 9 , wherein composite electrophoretic particle has a mass fraction of the polymer shell to the composite particle of at least 25 wt % to at most 40 wt %. 
     
     
         13 . The composite electrophoretic particle of  claim 9 , wherein the mass fraction of the polymer shell to the composite particle is measured by thermogravimetric analysis (TGA).