title: Nanoscopic Structural Investigation of Physically Cross-Linked Nanogels Formed from Self-Associating Polymers.
abstract: The detailed structure of a nanogel formed by self-association of cholesterol-bearing pullulans (CHPs) was determined by contrast variation small-angle neutron scattering. The decomposition of scattering intensities into partial scattering functions of each CHP nanogel component, i.e., pullulan, cholesterol, and the cross-term between the pullulan and the cholesterol, allows us to investigate the internal structure of the nanogel. The effective spherical radius of the skeleton formed by pullulan chains was found to be 8.1 ± 0.3 nm. In the CHP nanogel, there are about 19 cross-linking points where a cross-linking point is formed by aggregation of trimer cholesterol molecules, and the spatially inhomogeneous distribution of the cross-linking points in the nanogel can be represented by the mass fractal dimension of 2.6. The average radius of gyration of the partial chains can also be determined to be 1.7 ± 0.1 nm by analyzing the extracted cross-correlation between the cross-linker and the tethered polymer chain quantitatively, and the size agrees with the value assuming random distribution of the cross-linkers on the chains. As the result, the complex structure of the nanogels is coherently revealed at the nanoscopic level.
authors.affiliation: Materials Sciences Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan.
authors.forename: Yurina
authors.initials: Y
authors.lastname: Sekine
authors.affiliation: Neutron Science Laboratory, High Energy Accelerator Research Organization, 203-1 Shirakata, Tokai, Ibaraki 319-1106, Japan.|Department of Materials Structure Science, The Graduate University for Advanced Studies (SOKENDAI) , 203-1 Shirakata, Tokai, Ibaraki 319-1106, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Endo
authors.affiliation: Comprehensive Research Organization for Science and Society , 162-1 Shirakata, Tokai, Ibaraki 319-1106, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Iwase
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University , Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Takeda
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University , Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.|ERATO Bio-Nanotransporter Project, Japan Science and Technology Agency (JST), Kyoto University , Kastura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Sada-Atsu
authors.initials: SA
authors.lastname: Mukai
authors.affiliation: Materials Sciences Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fukazawa
authors.affiliation: Neutron Science Directorate, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831-6393, United States.
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Littrell
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University , Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.|ERATO Bio-Nanotransporter Project, Japan Science and Technology Agency (JST), Kyoto University , Kastura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sasaki
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University , Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.|ERATO Bio-Nanotransporter Project, Japan Science and Technology Agency (JST), Kyoto University , Kastura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Akiyoshi