Feb.4,2021  47  US 2021/0033971 Al  sulfonate, and nonafluorobutanesulfonate; arylsulfonate ions  such  as  tosylate,  benzenesulfonate,  4-fluorobenzene› sulfonate,  and  1,2,3,4,5-pentafluorobenzenesulfonate;  alkylsulfonate ions such as mesylate and butanesulfonate;  imide ions such as bis(trifluoromethylsulfonyl)imide, bis  (perfluoroethy lsulfony l)imide and bis(perfluoro buty lsulfo› nyl )imide; methide ions such as tris(trifluoromethylsulfo› nyl)methide and tris(perfluoroethylsulfonyl)methide.  [0106]  Also included are sulfonate ions having fluorine  substituted at a-position as represented by the formula  ( dl-1) and sulfonate ions having fluorine substituted at  a-position and trifluoromethyl at ~-position as represented  by the formula (dl-2).  [0107]  In formula (dl-1), R 31  is hydrogen or a C$_{1}$-C$_{20 }$ hydrocarbyl group which may contain an ether bond, ester  bond, carbonyl moiety, lactone ring, or fluorine atom. The  hydrocarbyl group may be saturated or unsaturated and  straight, branched or cyclic, and examples thereof are as will  be exemplified later for the hydrocarbyl group R 107  in  formula (IA’).  [0108]  In formula (dl-2),  R 32  is hydrogen, or a  C$_{1}$-C$_{30 }$ hydrocarbyl group,  C$_{2}$-C$_{30 }$ hydrocarbylcarbonyl group, or  C$_{6}$-C$_{20 }$ aryloxy group, which may contain an ether bond,  ester bond, carbonyl moiety or lactone ring. The hydrocarbyl  group and hydrocarbyl moiety of the hydrocarbylcarbonyl  group may be saturated or unsaturated and straight,  branched or cyclic, and examples thereof are as will be  exemplified later for the hydrocarbyl group R $^{107 }$in formula  (IA’).  [0109]  Examples of the cation in the monomer from which  recurring unit ( dl) is derived are shown below, but not  limited thereto.  RA  is as defined above.  [0102]  In formulae (dl) to (d3),  RA  is each independently  hydrogen or methyl. Z 1  is a single bond, phenylene,  -0-Z 11 -, ----C(=0)-0-Z 11 - or ----C(=0)-NH› Z11-, wherein Z 11  is a  C$_{1}$-C$_{6 }$ aliphatic hydrocarbylene  group or phenylene group, which may contain a carbonyl  moiety, ester bond, ether bond or hydroxyl moiety. Z 2  is a  single bond or ester bond. Z 3  is a single bond, -Z$^{31}$----C  (=0)-0-, -Z$^{31}$---0-,  or  -Z$^{31}$-0----C(=0)-,  wherein Z 31  is a  C$_{1 }$-C$_{12 }$ saturated hydrocarbylene group  which may contain a carbonyl moiety, ester bond, ether  bond, bromine or iodine. Z 4  is methylene, 2,2,2-trifluoro-l,  1-ethanediyl or carbonyl. Z 5  is a single bond, methylene,  ethylene, phenylene, fluorinated phenylene,  ---O-Z 51 -,  -C(=0)---0-Z 51 - or-C(=0)-NH-Z 51 -,  wherein  Z 51  is a  C$_{1}$-C$_{6 }$ aliphatic hydrocarbylene group, phenylene  group, fluorinated phenylene group, or trifluoromethyl-sub› stituted phenylene group, which may contain a carbonyl  moiety, ester bond, ether bond or hydroxyl moiety.  [0103]  In formulae (dl) to (d3),  R 21  to  R 28  are each  independently a C$_{1 }$-C$_{20 }$hydrocarbyl group which may con› tain a heteroatom. The hydrocarbyl groups R$^{21 }$to R$^{28 }$may  be saturated or unsaturated and straight, branched or cyclic.  Examples thereof include  C$_{1 }$-C$_{12 }$ alkyl groups,  CcC$_{12 }$ aryl  groups, and C$_{7}$-C$_{20 }$aralkyl groups. In these groups, some or  all hydrogen may be substituted by C$_{1 }$-C$_{10 }$saturated hydro› carbyl, halogen, trifluoromethyl, cyano, nitro, hydroxyl,  mercapto,  C$_{1 }$-C$_{10 }$ saturated hydrocarbyloxy,  C$_{2}$ -C$_{10 }$ satu› rated hydrocarbyloxycarbonyl, or C$_{2}$-C$_{10 }$ saturated hydro› carbylcarbonyloxy moiety, or some carbon may be replaced  by a carbonyl moiety, ether bond or ester bond.  [0104]  A pair of R$^{23 }$and R 24 , or R $^{26 }$and R$^{27 }$may bond  together to form a ring with the sulfur atom to which they are  attached. Examples of the ring are as will be exemplified  later for the ring that R$^{101 }$and R$^{102 }$in formula (1-1) form  with the sulfur atom to which they are attached.  [0105]  In formula (dl),  M- is a non-nucleophilic counter  ion. Examples of the non-nucleophilic counter ion include  halide ions such as chloride and bromide ions; fluoroal› ky lsulfonate ions such as triflate, 1, 1, 1-trifluoroethane- (d3)  R26  I  +s-R 27  I  R2s  (d2)  R23  I  +s-R24  I  R2s  (dl-1)  (dl-2)  -continued 