Polymer Structures

Small-angle X-ray scattering from the concentrated bulk phase separated from an amphiphilic block-copolymer solution


Aqueous solutions of the doubly thermosensitive block copolymer poly(2-isopropyl-2-oxazoline)-b-poly(2-ethyl-2-oxazoline) heated to 50 °C underwent a macroscopic liquid/liquid phase separation. The small-angle X-ray scattering intensity recorded from the concentrated phase settled on the bottom of a sample indicated that this phase was in the disordered state without any microphase separation, although the block copolymer was amphiphilic in water at 50 °C. It was also confirmed that the contribution to the scattering intensities of individual copolymer chains and their aggregates existing in the coexisting concentrated phase was very small, compared with the total scattering intensity of the phase-separated solution, when the concentrated phase was suspended in the form of colloidal droplets in the lean phase.

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The synchrotron radiation experiments were performed at the BL40B2 in SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal No 2013B1647). This work was supported in part by Grant-in-Aid for JSPS Research Fellow Grant number 16J00359 (R.T.).

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Correspondence to Takahiro Sato.

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Kondo, M., Takahashi, R., Qiu, X. et al. Small-angle X-ray scattering from the concentrated bulk phase separated from an amphiphilic block-copolymer solution. Polym J 49, 385–389 (2017). https://doi.org/10.1038/pj.2016.124

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