Volltext-Downloads (blau) und Frontdoor-Views (grau)

Nanoscale disintegration kinetics of mesoglobules in aqueous poly(N-isopropylacrylamide) solutions revealed by small-angle neutron scattering and pressure jumps

  • Identification and control of the disintegration mechanism of polymer nanoparticles are essential for applications in transport and release including polymer delivery systems. Structural changes during the disintegration of poly(N-isopropylacrylamide) (PNIPAM) mesoglobules in aqueous solution are studied in situ and in real time using kinetic small-angle neutron scattering with a time resolution of 50 ms. Simultaneously length scales between 1 and 100 nm are resolved. By initiating phase separation through fast pressure jumps across the coexistence line, 3 wt% PNIPAM solutions are rapidly brought into the one-phase state. Starting at the same temperature (35.1 °C) and pressure (17 MPa) the target pressure is varied over the range 25–48 MPa, allowing to systematically alter the osmotic pressure of the solvent within the mesoglobules. Initially, the mesoglobules have a radius of gyration of about 80 nm and contain a small amount of water. Two disintegration mechanisms are identified: (i) for target pressures close to the coexistence line, single polymers are released from the surface of the mesoglobules, and the mesoglobules decrease in size, which takes ∼30 s. (ii) For target pressures more distant from the coexistence line, the mesoglobules are swollen by water, and subsequently the chains become more and more loosely associated. In this case, disintegration proceeds within less than 10 s, controlled by the osmotic pressure of the solvent.

Download full text files

Export metadata

Additional Services

Share in Twitter Search Google Scholar


Document Type:Article
Author:Bart-Jan NiebuurORCiD, Leonardo ChiappisiORCiD, Florian A. JungORCiD, Xiaohan Zhang, Alfons SchulteORCiD, Christine M. PapadakisORCiD
Parent Title (English):Nanoscale
First Page:13421
Last Page:13426
Year of first Publication:2021
Release Date:2022/08/16
Impact:08.307 (2021)
Funding Information:Deutsche Forschungsgemeinschaft (PA 771/22-1)
DDC classes:500 Naturwissenschaften und Mathematik / 540 Chemie
Open Access:Open Access
Signature:INM 2021/084
Licence (German):License LogoCreative Commons - CC BY-NC - Namensnennung - Nicht kommerziell 4.0 International