In this thesis, structural and dynamic features of thermoresponsive amphiphilic pentablock copolymers have been studied for their potential use for drug delivery application. The copolymers are amphiphilic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO), also known as Pluronic, modified with hydrophobic poly(caprolactone) (PCL) to give the pentablock terpolymer PCL-PEO-PPO-PEO-PCL (PCLn-Pluronic-PCLn). The effects of the PCL length (n = 5 and 11) on the self-assembly properties of PCL-Pluronic-PCL in aqueous solutions have been investigated at various temperatures and both in the dilute and the semidilute concentration regimes. Turbidity measurements revealed a lower critical solution temperature, where the cloud point decreased with PCL length. Through dynamic light scattering (DLS) measurements, the polymers were found to form a mixture of micelles and intermicellar aggregates. A longer PCL length resulted in larger intermicellar aggregates. Small angle neutron scattering (SANS) measurements revealed that the polymers with a short PCL length formed spherical flower-like micelles, whereas the polymers with a long PCL length formed elongated cylindrical micelles. In the semidilute concentration region, the polymers form thermoreversible hydrogels at elevated temperatures. The gel window in the phase diagrams for these polymers greatly depends on the PCL length, where a longer PCL length decreases the concentration and temperature needed for gelation. The dynamic properties of the gels were characterized by rheology. SANS measurements revealed a tight ordering of the micelles in these systems, and demonstrated interesting conformational differences between the systems.