Block Copolymer-Comprising Compositions and Methods of Purifying PS-b-PXVP

A method of purifying PS-b-PXVP from a solution comprising dissolved PS-b-PXVP and a dissolved lithium salt, where “X” is 2 or 4, comprising:

• providing a solution comprising dissolved PS-b-PXVP and a dissolved lithium salt, where “X” is 2 or 4, the solution comprising a carbon-containing liquid solvent, the carbon-containing liquid solvent being soluble in liquid water;
• combining the carbon-containing liquid solvent having the dissolved solid with liquid water and precipitating a first precipitate therefrom, the first precipitate having greater concentration PS-b-PXVP and less concentration lithium salt than was in the solid;
• dissolving the first precipitate in an organic liquid solvent that can form an azeotrope with water;
• combining the organic liquid solvent having the dissolved first precipitate with liquid water and forming an aqueous liquid phase and an organic liquid phase therefrom;
• separating the organic liquid phase from the aqueous liquid phase;
• and
• after the separating, boiling away liquid from the organic liquid phase to leave a resultant precipitate, the first precipitate having more water than any water in the resultant precipitate, the resultant precipitate having greater concentration PS-b-PXVP and less concentration lithium salt than was in the solid.

A method of purifying PS-b-PXVP from a solid comprising PS-b-PXVP and a lithium salt, where “X” is 2 or 4, comprising:

• dissolving the solid in liquid tetrahydrofuran;
• combining the liquid tetrahydrofuran having the dissolved solid with liquid water and precipitating a first precipitate therefrom, the first precipitate having greater concentration PS-b-PXVP and less concentration lithium salt than was in the solid;
• dissolving the first precipitate in liquid dichloromethane;
• combining the liquid dichloromethane having the dissolved first precipitate with liquid water and forming an aqueous liquid phase and an organic liquid phase therefrom;
• separating the organic liquid phase from the aqueous liquid phase;
• and
• after the separating, boiling away liquid dichloromethane from the organic liquid phase to leave a resultant precipitate, the first precipitate having more water than any water in the resultant precipitate, the resultant precipitate having greater concentration PS-b-PXVP and less concentration lithium salt than was in the solid.