Compositions having HASE rheology modifiers

A method for fracturing a geologic formation, comprising directing a stream of an aqueous composition at a surface of the formation at a pressure and flow rate at least sufficient to initiate, extend, or initiate and extend one or more fractures in the formation,

• the aqueous composition, comprising:
• (I) water
• (II) a pH responsive polymer comprising, based on the total weight of monomeric units,
• (a) from about 25 to about 70 percent by weight acid monomeric units, each independently comprising a carboxylic acid-functional substituent group,
• (b) from about 30 to about 70 percent by weight nonionic monomeric units, each independently comprising a nonionic substituent group, and
• (c) from about 0.05 to about 20 percent by weight hydrophobic monomeric units, each independently comprising a functional group according to structure (I):
• —R13—R12—R11 (I)
• wherein:
• R11 is bicyclo[d.e.f]heptyl or bicyclo[d.e.f]heptenyl, wherein d is 2, 3, or 4, e is 1 or 2, f is 0 or 1, and the sum of d+e+f=5, and which may, optionally, be substituted on one or more of the ring carbon atoms by one or more (C1-C6)alkyl groups,
• R12 is absent, —OCvH2v—,
• or —O—CH(R16)—CH(R17)—O—, wherein v is an integer of from 1 to 6, and R14, R15, R16, and R17 are each independently H or (C1-C6)alkyl,
• R13 a bivalent polyoxyalkylene group according to structure (VIII):
• wherein:
• p′ is 2 or 3 and q is 2 or 3, provided that p′ is not equal to q,
• each r is independently an integer of from 1 to about 50,
• each s is independently an integer of from 1 to about 50, and
• t is 1, and
• (III) at least one of:
• (a) one or more surfactants selected from anionic surfactant, cationic surfactants, nonionic surfactants, amphoteric surfactants, zwitterionic surfactants, and mixtures thereof, and
• (b) particles dispersed in the composition.