10  US 9,046,772 B2  9  Monomer  In the first embodiment, the invention provides a monomer  having the general formula  (1).  :io  0  \I  ~kl  0  4  R2  Rs  R  R  R6  R  R7  }A  OYRIO  0  (1)  -continued  y---y---› ~---- y0---- Herein and throughout the specification, the broken line des› ignates a valence bond.  In some embodiments, R $^{4 }$and R $^{8 }$bond together to form a 5  or 6-membered ring, examples of which are shown below  wherein R $^{10 }$is as defined above.  Herein R$^{1 }$is hydrogen, methyl or trifluoromethyl. R$^{2 }$and R 3  are each independently a straight, branched or cyclic monova› lent hydrocarbon group of  1  to  10  carbon atoms. R 2  and R 3  may bond together to form a ring with the carbon atom to  which they are attached. R 4  to R 9  are each independently  hydrogen or a straight, branched or cyclic monovalent hydro› carbon group of  1  to  10  carbon atoms. R 4  and R$^{8 }$may bond  together to form a 5 or 6-membered ring with the carbon  atoms to which they are attached. R $^{10 }$is a straight, branched  or cyclic monovalent hydrocarbon or fluorinated hydrocar› bon group of  1  to 15 carbon atoms. A $^{1 }$is a straight, branched  or cyclic divalent hydrocarbon group of  1  to  10  carbon atoms,  k $^{1 }$is  O or 1,  and n 1 A  is an integer of0 to 2.  Typical straight, branched or cyclic, monovalent C$_{1 }$-C$_{10 }$ hydrocarbon groups represented by R$^{2 }$to R$^{9 }$are alkyl groups  including methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl,  tert-butyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, n-octyl,  norbornyl, tricyclodecanyl, and adamantyl.  In some embodiments, R$^{2 }$and R$^{3 }$bond together to form a  ring, examples of which are shown below.  . 0  G  .  ’  ’  ’  ’  :  0---- o--- ---- ’  ’  ’  u---- u  ----