Interaction of ABA block copolymers with ionic surfactants: influence on micellization and gelation

E Hecht, K Mortensen, M Gradzielski… - The Journal of …, 1995 - ACS Publications
E Hecht, K Mortensen, M Gradzielski, H Hoffmann
The Journal of Physical Chemistry, 1995ACS Publications
At higher concentrations the micelles form a liquid crystalline gel with a body-centered cubic
structure. 2· 8-10· 14 This gel shows inverse temperature behavior; that is, with increasing
temper-ature the aqueous solution is transformed into a stiff gel with a high yield stress
value. 2 Further increase of temperature leads to a breakdown of the gel structure,
againresulting in a solution with low viscosity. 5· 6 The temperature range for the gel phase
depends on the poloxamer concentration and increases with increasing concentration. The …
At higher concentrations the micelles form a liquid crystalline gel with a body-centered cubic structure. 2· 8-10· 14 This gel shows inverse temperature behavior; that is, with increasing temper-ature the aqueous solution is transformed into a stiff gel with a high yield stress value. 2 Further increase of temperature leads to a breakdown of the gel structure, againresulting in a solution with low viscosity. 5· 6 The temperature range for the gel phase depends on the poloxamer concentration and increases with increasing concentration. The existence of the gel phase can be influenced by addition of the homopolymers PEO or PPO. 15 Addition of PEO results in a decreasing stability of the gel. With increasingPEO concentration the temperature range for the gel phase decreases and finally vanishes at a sufficiently high concentration. Low molecular weight PPO, on the other hand, increases the stability region of the gel, which is a consequence of the solubilization of the latter in the block copolymer micelles.
ACS Publications