TY  - JOUR
AU  - Gold, Barbara
AU  - Hövelmann, C. H.
AU  - Lühmann, N.
AU  - Szekely, Noemi
AU  - Pyckhout-Hintzen, W.
AU  - Wischnewski, A.
AU  - Richter, D.
TI  - Importance of Compact Random Walks for the Rheology of Transient Networks
JO  - ACS Macro Letters
VL  - 6
IS  - 2
SN  - 2161-1653
CY  - Washington, DC
PB  - ACS
M1  - FZJ-2017-07506
SP  - 73 - 77
PY  - 2017
AB  - Controlling the mechanical behavior of novel supramolecular materials is of the utmost importance and requires a fundamental understanding of the underlying physical processes. We present a multimethods approach to the dynamics of entangled transient polyisoprene networks. Small-angle neutron scattering (SANS) on randomly functionalized chains shows homogeneous supramolecular melts with Gaussian chain conformations. The H-bond lifetimes (dielectric α*-process) and the rheological response in terms of the loss modulus G″ differ by 2 orders of magnitude in time. Within the concept of a compact random walk (RW), where the random walker (urazole group acting as a sticker) undergoes multiple returns to its starting point and following the concept of theoretical proposed renormalized sticky bond lifetimes, we quantitatively solve this longstanding and unexplained large discrepancy: While the bond opening gives rise to the dielectric response, for rheological relaxation the association with a new partner is relevant. This takes place only after multiple returns to the original binding partner.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000394732000002
DO  - DOI:10.1021/acsmacrolett.6b00880
UR  - https://juser.fz-juelich.de/record/839928
ER  -