Patent ID: 8039447

Claim:
A method for preparing a viscoelastic composition, comprising: adding to fluid a compound having the following formula (I): wherein: n represents an integer varying from 720 to 6 200, i varies from 1 to n, R i represents: OH, OZ, wherein Z represents any monovalent counterion or any divalent counterion, or a group of the following formula (II): wherein: k represents an integer varying from 1 to 17, or a group of the following formula (III): wherein: k represents an integer varying from 1 to 17 R′ i represents a linear or branched alkyl chain comprising p carbon atoms, wherein p is an integer varying from 1 to 17, with proviso that k+p is not greater than 28, and wherein at least one R i group represents a group of formula (III).