Authors Müller, T. ; Sommer, J.-U. ; Lang, M.
Title Elasticity of tendomer gels
Date 29.08.2022
Number 60613
Abstract We investigate the formation and the elastic properties of tendomer networks (i.e., slide-ring gels with “ storage chains” containing free sliding rings) with computer simulations. An analysis of the gel point shows that network formation is only possible up to a limiting number of slide rings per tendomer. Tendomer networks are super soft and quasi-entanglement-free model systems with extreme stretchability. The elastic properties of tendomers are dominated by the phantom contribution to modulus, which develops significant deviations from the mean field prediction. These can be explained with corrections from the formation of finite loops, differences between mean field behavior, and critical scaling near the gel point and additional contributions due to prestrain at high extents of reaction. A strong enhancement of the modulus by 2 orders of magnitude can be achieved by preparation in a selective solvent that is poor only for the slide rings. With this procedure, also the limit in the number of slide rings for network formation can be increased. The deformation of the chains is neither linear nor uniform since the force-elongation behavior of individual tendomers contains a critical force beyond which chains can be deformed at almost no increase in the applied force. Deformation of a network, thus, splits the tendomer units into two populations: those beyond and below the critical force that are either largely stretched or remain in a subcritical extension. This splitting causes a continuous strain softening for larger deformations even in the absence of entanglements and prior to the onset of finite extensibility effects. This observation contrasts the strain hardening originally observed for conventional slide ring gels and agrees with more recent experimental data on these gels.
Publisher Macromolecules
Citation Macromolecules 55 (2022) 7540-7555

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