| 초록 |
The retention time of PEO becomes increase at high temperature. The PEO chains can strongly undergo hydrophobic interaction with the stationary phase of the column. The temperature dependency is influenced by the kinds of the salt, and gets stronger at high concentration of the salt. The ions formed from the salt can hinder the hydrogen bonding between PEO chains and water molecules. The high molecular weight PEO can be fully adsorbed onto the stationary phase. This temperature dependency is also changed as the PEO forms block copolymer with other polymers, and homo PEO can be completely separated from the PEO contained block copolymer (PEO-b-Poly(methacrylic acid)). The PEO retention in the block copolymer is less influenced by temperature than the homo PEO since it can have strong interaction with water molecules due to negative charge of PMAA block. Here, the enthalpy stabilization by polar interaction exceeds entropy penalty of the surrounding water molecules at high temperature. |
