Journal Article

PreJuSER-8965

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Thermoresponsive PS-b-PNIPAM-b-PS Micelles: Aggregation Behavior, Segmental Dynamics, and Thermal Response

Adelsberger, J. ; Kulkarni, A. ; Jain, A. ; Wang, W. ; Bivigou-Koumba, A. M. ; Busch, P.FZJ* ; Pipich, V.FZJ* ; Holderer, O.FZJ* ; Hellweg, T. ; Laschewsky, A. ; Müller-Buschbaum, P. ÜFZJ* ; Papadakis, C. M.

2010
Soc. Washington, DC

This record in other databases:  

Please use a persistent id in citations: doi:10.1021/ma902714p

Abstract: We have studied I lie thermal behavior of amphiphilic, symmetric triblock copolymers having short, deuterated polystyrene (PS) end blocks and a large poly(N-isopropylacrylarnicle) (PNIPAM) middle block exhibiting a lower critical solution temperature (LCST) in aqueous solution. A wide range of concentrations (0.1-300 mg/mL) is investigated using it number of analytical methods such as fluorescence correlation spectroscopy (FCS), turbidimetry, dynamic light scattering (DLS), small-angle neutron scattering (SANS), and neutron spin-echo spectroscopy (NSE). The critical micelle concentration is determined using FCS to be 1 mu M or less. The collapse of the micelles at the LCST is investigated using turbidimetry and DLS and shows a weak dependence on the degree of polymerization of the PNIPAM block. SANS with contrast matching allows its to reveal the core-shell Structure of the micelles as well as their correlation as a function of temperature. The segmental dynamics of the PNIPAM shell are studied as a function of temperature and arc found to be faster in the collapsed state than in the swollen state. The mode detected has a linear dispersion in q(2) and is found to be faster in the collapsed state as compared to the swollen state. We attribute this result to the averaging over mobile and immobilized segments.

Keyword(s): J

Note: We thank W. Doster and A.-K. Sommer for assistance with the DLS experiments and fruitful discussions. We kindly acknowledge given beam time by the Julich Centre for Neutron Science at FRM II. This work was supported by the DFG priority program SPP1259 "Intelligente Hydrogele" (Pa771/4 Mu1487/8, La611/7, He2995/2-2). A.M.B.-K. gratefully acknowledges a personal grant from Deutscher Akademischer Austauschdienst (DAAD).

---

Contributing Institute(s):

1. Streumethoden (IFF-4)
2. JCNS (Jülich Centre for Neutron Science JCNS (JCNS) ; JCNS)

Research Program(s):

1. BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung (P45)

Experiment(s):

1. J-NSE: Neutron spin-echo spectrometer (NL2ao)
2. KWS-2: Small angle scattering diffractometer (NL3ao)

Appears in the scientific report 2010

---