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The monomer Ma may be synthesized by reacting (meth) acrylic acid with an iodized hydroxylactone to form a (meth)acrylate. Examples of the monomer Ma are shown below, but not limited thereto. Herein RA is as defined above. 

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Preferably the recurring units (bl) and (b2) have the formulae (bl) and (b2), respectively. 

Herein RA is as defined above. R$^{3 }$and R 4 each are an acid labile group. R 5 is hydrogen, fluorine, trifluoromethyl, cyano, or a C$_{1 }$-C$_{6 }$ straight, branched or cyclic alkyl group. R $^{6 }$is a single bond or a C$_{1 }$-C$_{6 }$ straight or branched alkylene group in which at least one carbon atom may be substituted by an ether or ester moiety, p is 1 or 2, and q is an integer ofO to 4. X$^{1 }$is a single bond, a C$_{1}$-C$_{14 }$linking group which contains an ester, ether moiety or lactone ring, a phenylene group or a naphthylene group. X 2 is a single bond, ----C(=0)---0- or ----C(=O)-NH-. 

Monomers Mbl and Mb2 from which the recurring units (bl) and (b2) are derived are represented by the formulae (Mbl) and (Mb2), respectively. 

Herein RA, R 3 to R 6 , X1, X 2 , p and q are as defined above. 

Examples of the monomer Mbl are given below, but not limited thereto. Herein RA and R 3 are as defined above. 

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(bl) 

(b2) 

(Mbl) 

(Mb2) 

