User:Andrew Sun/Notebook/LAOS study on physical gelation/2009/05/06

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LAOS Experiment of PAAc/Fe(III) Gels

Objectives

Effect of different molecular weights.

Samples

Gels from 5 wt% PAAc solution (Mv=44500): f=1.30e-3 (f=[Fe(III)]/[COOH])

Instrument

ARES Rheometry

Results

Frequency Sweep

Fig. 1
Fig. 1

Frequency sweep result (Fig. 1 1st run) indicates that the sample was below the critical point. During LAOS experiment, the sample exhibit slight drop in stress amplitude τ0 with time. Comparison between frequency sweeps before and after LAOS experiment (Fig. 1) indicate minor dissociation of network in the sample.

FT-Rheology

There is hardly significant 3rd harmonics found at all strain amplitudes.


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