| abstract |
The present invention relates to a composition with pH-dependant viscosity, comprising (A) at least one surfactant of the general formula (I), (R<SUP>1</SUP>-[(O-(CH<SUB>2</SUB>)<SUB>2</SUB>)<SUB>x1</SUB>(O-CH(CH<SUB>3</SUB>)CH<SUB>2</SUB>)<SUB>x2</SUB>]O)<SUB>k</SUB>P(=O)(OH) (I), wherein the sequence of the alkenoxy units is optional, R<SUP>1 </SUP>is selected from linear or branched C<SUB>12</SUB>-C<SUB>22</SUB>-alkyl, C<SUB>12</SUB>-C<SUB>22</SUB>-alkenyl, C<SUB>12</SUB>-C<SUB>22</SUB>-alkinyl, (C<SUB>11</SUB>-C<SUB>21</SUB>-alkyl)carbonyl, (C<SUB>11</SUB>-C<SUB>21</SUB>-alkenyl)carbonyl and (C<SUB>11</SUB>-C<SUB>21</SUB>-alkinyl)carbonyl, k is 1 or 2, and x1 and x2 independently from each other are an integer from 0 to 20, wherein the sum of x<SUP>1</SUP> und x<SUP>2 </SUP>is a number from 1 to 20, and (B) at least one thickener. comprising at least two hydrophobic groups R<SUP>2</SUP>, which are connected with each other via a bridging hydrophilic group (a). The invention further relates to the use for the controlled adjustment of the rheological properties of aqueous compositions and to methods for the treatment of underground geological formations. |