Sep. 10,2020  39  US 2020/0285149 Al  [0098]  Examples of the monomer from which recurring  unit (f3) is derived are shown below, but not limited thereto.  RA  is as defined above.  -continued  -continued  RA  }-o  0  0  o~c Q  S03- +s--0  0  6  0  RA  o~c Q  0  S03- 6  0  Oi-R•  0  o~c Q  S03- 6 