Abstract
AbstractBy using L‐proline N‐carboxyanhydride (LPNCA) and amino‐group terminated poly(ethylene oxide) (ATPEO), an A–B–A–type [A = poly(L‐proline) (PLP), B = poly(ethylene oxide) (PEO)] triblock copolymer (POP) was prepared which is water‐soluble. In the POP, A = PLP is helical, and B = PEO is random coil. From the observations of the NMR spectra, specific optical rotation, and x‐ray diffraction of the POP, it was found that the PLP component of the POP exists nearly as Form II PLP with trans‐configuration, and interferes the crystal growth of PEO component, in solid state. With the addition of PMAA into an aqueous POP solution, dramatic decreases of reduced viscosity and pH are observed until the unit‐mole‐concentration‐ratio (UMCR) [PMAA]/[POP] reaches its value of unity, while a distinct increase in turbidity appears. This shows a 1 : 1 interpolymer complex formation between PMAA and POP in aqueous medium through hydrogen bonding. The curves of viscosity, pH, and turbidity versus UMCR [PMAA]/[POP] show breaks at [PMAA]/[POP] = 0.3, suggesting the selective complexation of PLP component (ca. 30 unit‐mol %) of POP with PMAA. The x‐ray diffraction curve of the complex POP/PMAA shows entirely no diffraction patterns, indicating that the ordered POP structure (mainly due to that of PLP component) is completely destroyed owing to the complexation between POP and PMAA.
Published Version
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