Amphiphilic Polymeric micelle or emulsion has been extensively used in fields of nanomedicines and cosmetics because of its targeting delivery function. In order to make the best use of its character,
it is often required to control local physicochemical properties (packing density, flexibility) of the micelle core. Dynamic property of the micelle core can be modified by mixing the micelle with an amphiphilic surfactant since the flexibility of the micelle core is solely controlled by intermolecular forces (Van der
Waals force) between of them. Up to now, there have been many efforts to measure the features with mechanical or spectroscopic techniques, however, none of them were not able to investigate the characters in detail and precisely.
Here, we have intensively investigated the dynamic features of PEO-b-PCL / surfactant (phospholipid and its derivatives) mixtures by NMR spectroscopy. Several NMR parameters including spin relaxation rates and diffusion coefficient are employed to determine the optimal concentration ratio between the block copolymer and a surfactant. As a result, we found that physicochemical character of the micelle is highly dependent on feature of the surfactants explained by symmetricity, number, and length of hydrophobic chains.