Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 20: (Hydro)gels and Elastomers

CPP 20.4: Talk

Wednesday, March 28, 2012, 10:15–10:30, C 264

Determination of viscoelastic properties of adsorbed thermo responsive gel particles via AFM tip indentation — •Marcel Richter and Regine von Klitzing — TU Berlin, Straße des 17.Juni 124, 10623 Berlin

During the last decades microgels made of N-isopropylacrylamide (NIPAM) have attracted much interest and were studied by several techniques like atomic force microscopy (AFM) and dynamic light scattering (DLS) [1]. These polymer particles show thermo responsive behaviour and can therefore be classified as "smart" materials. For the later adsorption behaviour of nano- and micro-objects like colloidal particles or cells on top of adsorbed microgel layers the mechanical properties of such microgels are of great interest. Here, the AFM tip indentation method is a suitable method for the determination of the Young`s modulus [2]. We synthesised microgel particles with different co-monomers and study the stiffness according to the cross linker and co-monomer amount. The measurements show a tremendous shift in the lower critical solution temperature (LCST) and change in (visco) elasticity. The size of microgels is determined by Dynamic Light Scattering and Scanning Force Microscopy.

[1] K. Kratz, T. Hellweg, W. Eimer, Polymer (2001), 42, 6531

[2] E. K. Dimitriadis et al, Biophysical Journal, (2002), 82, 2798