Triblock copolymer PE6200 (PEO10.5-PPO30-PEO10.5) in aqueous solution can undergo a transition from an isotropic micellar phase to an anisotropic lamellar phase at a specific temperature. Based on this feature, the self-assembly behavior of a benzenetetracarboxylic acid based hydrogelator in aqueous solutions of PE6200 has been investigated. The results of small angle X-ray scattering (SAXS) measurements indicated that the hydrogelator self-assembled into stable three-dimensional network structures below 50 degrees C. In the range of 50-60 degrees C, a transition from three-dimensional to two-dimensional self-assembly was observed, which can be attributed to the fact that PE6200 undergoes a transition from an isotropic micellar phase to an anisotropic lamellar phase. Differential scanning calorimetry (DSC) and varying temperature laser Raman spectroscopy further confirmed the thermodynamically controllable transition of 3D to 2D self-assembly. Controlling the self-assembly by utilizing the phase behavior of triblock copolymers is a novel strategy. (C) 2012 Elsevier Inc. All rights reserved.