Amphiphilic thermo-responsive multiblock polycarbonates consisting of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) were facilely synthesized using triphosgene as coupling agent. The structures and molecular characteristics of the polycarbonates were confirmed by H-1-NMR, FT-IR and Gel permeation chromatography (GPC). The crystallization behavior and thermal properties of the polycarbonates were studied using X-ray diffraction (XRD), Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Surface tension measurements confirmed that the critical micelles concentration of polymeric micelles were concentration ranges, which varied from about 2-70 mg/L to 5-40 mg/L with increasing PEO/PPO composition ratio from 0.8 to 1. Dynamic light scattering (DLS) experiments showed bimodal size distributions, the aggregates size increased with increasing the concentration of the polycarbonates aqueous solutions. The size of the aggregates acquired from TEM was smaller than that from DLS owing to the fact that TEM gave size of the aggregates in dry state rather than the hydrodynamic diameter. The degradation process revealed that the degradation rate of the aggregates could be accelerated with an increase in temperature. Moreover, the more the polycarbonate was hydrophilic, the faster was its degradation. Rheological measurements Suggested that these multiblock polycarbonates were thermo-responsive and by regulating the PEO/PPO composition ratio they Could form a gel at 37 degrees C. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 1425-1435, 2009