title: Stabilized micelles of amphoteric polyurethane formed by thermoresponsive micellization in HCl aqueous solution.
abstract: The thermoresponsive micellization behavior of amphoteric polyurethane (APU) was studied in HCl aqueous solution (pH 2.0) through light scattering, transmission electron microscopy, and fluorescent measurement. When APU concentration is high enough, nonreversible assembly of macromolecules can be observed with temperature decreasing from 25 to 4 degrees C. However, micelles reaching equilibrium at 4 degrees C can self-assemble reversibly in the temperature range of 4-55 degrees C. According to our research, we found it is the temperature sensitivity of the poly(propylene oxide) (PPO) segments that leads to the reassembly of APU at lower temperature. We proposed that core-shell-corona micelles ultimately form with hydrophobic core, PPO shell, and hydrophilic corona when temperature increases from 4 to 25 degrees C. This structure is very stable and does not change at higher temperatures (25-55 degrees C). That provides a new way to obtain stable micelles with small size and narrow size distribution at higher concentration of APU.
authors.affiliation: School of Material Science and Technology, and School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Qiao
authors.forename: Shifeng
authors.initials: S
authors.lastname: Zhang
authors.forename: Ouya
authors.initials: O
authors.lastname: Lin
authors.forename: Liandong
authors.initials: L
authors.lastname: Deng
authors.forename: Anjie
authors.initials: A
authors.lastname: Dong