The study of multiphase polymer systems represents a tremendous importance in many fields such as polymer blends, formulated materials or reinforced polymer alloy. By the way, interfacial rheology is a powerful tool to probe interfaces and surfaces. Developing new interfacial rheological tools to study polymer systems is nowadays a subject of increasing interest in the industrial and academic organizations. The current main devices/geometries dedicated to characterize interfaces are the bicone and double-wall Ring (DWR). They can easily be linked to standard rheometers. However, measurements are made below 70 ° C to ensure a stable homogeneous temperature at the interface. Meanwhile, each device has its limitation: the bicone has high inertia and a relatively low Boussinesq number, giving it a low signal-to-noise ratio, while the DWR, because of its fragility, is not suitable to measure the interfaces of high viscous systems and particularly in the molten state. In the present work a new high temperature resistant interfacial rheology cell coupled to an actively peltier-temperature-controlled hood has been designed. To enhance the inertia sensitivity, a new biconical titanium-based measuring system was developed allowing more accurate measurements. Particular attention has been paid to probe interfaces between two immiscible polymers in the molten state. Polycaprolactone (PCL) and polyethene glycol (PEG) were choosen for this purpose. The effects of the molecular weight and the temperature were highlighted. The measured apparent interfacial shear properties in both oscillatory and steady flow regimes were carefully corrected, considering the contribution of the subphases during the gathering of the numerical data.