content_image/907399.jpg content_image/907407.jpg content_image/907400.jpg content_image/907406.jpg
Monomer 

In the first embodiment, the invention provides a monomer having the general formula (1). 

<img src='content_image/907399.jpg'>

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. 

<img src='content_image/907407.jpg'>

<img src='content_image/907400.jpg'>

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. 

<img src='content_image/907406.jpg'>

