Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Feb 22;11(2):382.
doi: 10.3390/polym11020382.

Effect of Hydration in Corona Layer on Structural Change of Thermo-Responsive Polymer Micelles

Yusuke Akino  1 , Kosuke Morimoto  2 , Kengo Tsuboi  3 , Satoshi Kanazawa  4 , Isamu Akiba  5
Affiliations

Effect of Hydration in Corona Layer on Structural Change of Thermo-Responsive Polymer Micelles

Yusuke Akino et al. Polymers (Basel). .

Abstract

The effect of hydration in corona layer on temperature responsiveness of polymer micelles consisting of poly(N-vinyl pyrrolidone)-block-poly(n-octadecyl acrylate) (PVP-b-PODA) was investigated. Small-angle X-ray scattering and dynamic light scattering showed two-step shape change of PVP-b-PODA micelles around 45 and 65 °C with elevating temperature, although only one-step shape change was observed at 45 °C in cooling process. In the first step, shape of PVP-b-PODA micelles was changed from disk to ellipsoidal oblate at the melting temperature (Tm) of PODA, although similar micelles consisting of another amphiphilic block copolymers containing PODA simply changed from disk to sphere at the Tm with elevating temperature. PVP-b-PODA micelles changed to spherical shape above 65 °C. Two-dimensional (2D) ¹H-NMR showed the PVP chains were perfectly dehydrated above 65 °C. Therefore, it was suggested that the appearance of ellipsoidal shape between Tm of PODA and 65 °C was caused owing to shape memory effect of pseudo network of corona layer due to robust hydration of PVP chains.

Keywords: hydration; polymer micelle; small-angle X-ray scattering; temperature responsiveness.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Scheme 1
Scheme 1
Synthesis of poly(N-vinyl pyrrolidone)-block-poly(n-octadecyl acrylate) (PVP-b-PODA) by reversible addition-fragmentation chain transfer (RAFT) polymerization.
Figure 1
Figure 1
Change in hydrodynamic radius (Rh) of PVP-b-PODA micelles with varying temperature.
Figure 2
Figure 2
Changes in small-angle X-ray scattering (SAXS) profiles (a) and Invarian Q (b) of PVP-b-PODA micelles with elevating temperature.
Figure 3
Figure 3
Fitting analyses of SAXS profiles of PVP-b-PODA micelles at 25, 60, and 70 °C by using core-shell disk, oblate, and sphere, respectively.
Figure 4
Figure 4
Two-dimensional (2D) 1H-NMR (NOESY) spectra of PVP-b-PODA micelles measured at 25, 60, and 70 °C.
Figure 5
Figure 5
Schematic illustration of molecular mechanism of two-step temperature responsiveness of PVP-b-PODA micelles in heating process.
See this image and copyright information in PMC

References

    1. Zhang L.F., Eisenberg A. Multiple Morphologies of “Crew-Cut” Aggregates of Polysyrene-b-poly(acrylic acid) Block Copolymers. Science. 1995;268:1728–1731. doi: 10.1126/science.268.5218.1728. - DOI - PubMed
    1. Yokoyama M. Polymeric Micelles for the Targeting of Hydrophobic Drugs. In: Kwon G.S., editor. Polymeric Drug Delivery Systems. Taylor & Francis; Boca Raton, FL, USA: 2005. pp. 533–575. Drugs and the Pharmaceutical Sciences 148.
    1. Monfardini C., Veronese F.M. Stabilization of Substances in Circulation. Bioconjugate Chem. 1998;9:418–450. doi: 10.1021/bc970184f. - DOI - PubMed
    1. Matsumura Y., Kimura M., Yamamoto T., Maeda H. Involvement of the Kinin-generating Cascade in Enhanced Vascular Permeability in Tumor Tissue. Jpn. J. Cancer Res. 1988;79:1327–1334. doi: 10.1111/j.1349-7006.1988.tb01563.x. - DOI - PMC - PubMed
    1. Yamamoto T., Yokoyama M., Opanasopit P., Hayama A., Kawano K., Maitani Y. What Are Determining Factors for Stable Drug Incorporation into Polymeric Micelle Carriers? Consideration on Physical and Chemical Characters of the Micelle Inner Core. J. Control. Release. 2007;123:11–18. doi: 10.1016/j.jconrel.2007.07.008. - DOI - PubMed

LinkOut - more resources