Light emitting polymer

Abstract

There is provided a process for forming a light emitting polymer comprising photopolymerization of a reactive mesogen having an endgroup which is susceptible to photopolymerization e.g. by a radical polymerization process. Also provided are methods for using the light emitter in displays, backlights, electronic apparatus and security viewers.

1 . A light emitting or charge transporting polymer comprising a polymer formed from reactive mesogens having the formula:  
         B—S-A-S—B● 
       wherein 
 A is a chromophore of general formula —(Ar-Fl) n -Ar— 
 wherein  
 Ar is an aromatic diradical or a heteroaromatic diradical bonded linearly or substantially linearly to adjoining diradicals, or a single bond;  
 Fl is a 9,9-dialkyl substituted fluorene diradical joined to adjoining diradicals at the 2 and 7 positions;  
 the Ar and Fl diradicals may be chosen independently in each of the n subunits of the chromophore; and  
 1≦n≦10,  
 S is a spacer;  
 B is an unradicalised endgroup which is susceptible to polymerization; and  
 B● is a radicalised endgroup.  
 
     
     
         2 . The polymer of  claim 1 , wherein the B● radicalised endgroup is able to react with the unradicalised endgroup (B) to form a cyclic entity.  
     
     
         3 . The polymer of  claim 2 , wherein the reaction of the B● radicalised endgroup with the unradicalised endgroup (B) is susceptible to steric control.  
     
     
         4 . The polymer of  claim 1 , wherein the unradicalised endgroup B is susceptible to photopolymerization.  
     
     
         5 . The polymer of  claim 4 , wherein the polymer is formed by photopolymerization.  
     
     
         6 . The polymer of  claim 1 , wherein the unradicalised endgroup (B) comprises a diene.  
     
     
         7 . The polymer of  claim 6 , wherein the diene is selected from the group consisting of 1,4 dienes, 1,5 dienes and 1,6 dienes.  
     
     
         8 . The polymer of  claim 6 , wherein the diene functionalities are separated by an aliphatic linkage.  
     
     
         9 . The polymer of  claim 6 , wherein the diene functionalities are separated by an inert linkage.  
     
     
         10 . The polymer of  claim 9 , wherein inert linkage is selected from the group consisting of ether and amine linkages.  
     
     
         11 . The polymer of  claim 1 , wherein the light emitting or charge transporting polymer is a light emitting electroluminescent polymer.  
     
     
         12 . The polymer of  claim 1 , wherein light emitting or charge transporting polymer is a hole transporting polymer.  
     
     
         13 . The polymer of  claim 1 , wherein the light emitting or charge transporting polymer is an electron transporting polymer.  
     
     
         14 . The polymer of  claim 1 , wherein the light emitting or charge transporting polymer is substantially photoinititor free.  
     
     
         15 . The polymer of  claim 1 , wherein 2≦n≦7.