Stress Buildup under Start-Up Shear Flows in Self-Assembled Transient Networks of Telechelic Associating Polymers
Bibliographic record
Abstract
The nonaffine transient network theory is used to study the time development of the shear and normal stresses under start-up shear flows in networks formed by self-assembled telechelic, hydrophobically modified water-soluble polymers. The initial slope, strain hardening, and overshoot of the shear stress are studied in detail in relation to the nonlinear tension-elongation curve of the elastically active chains in the network. The condition for the occurrence of strain hardening (upward deviation of the stress from the reference curve defined by the linear moduli) is found to be gamma > gammac(A), where gamma is the shear rate, gamma(c) is its critical value for strain hardening, and A is the amplitude of the nonlinear term in the tension of a chain. The critical shear rate gamma(c) is calculated as a function of A. It is approximately 6.3 (in the time unit of the reciprocal thermal dissociation rate) for a nonlinear chain with A = 10. The overshoot time t(max) when the stress reaches a maximum and the total deformation gamma(max) = gamma(t max) accumulated before the peak time are obtained in terms of the molecular parameters of the polymer chain. The maximum deformation gamma(max) turns out to depend weakly upon the shear rate gamma. The first and second normal stress differences are also studied on the basis of the exact numerical integration of the theoretical model by paying special attention to their overshoot, undershoot, and sign change as a function of the shear rate. These theoretical results are compared with recent rheological experiments of the solutions of telechelic hydrophobically modified poly(ethylene oxide)s carrying short branched alkyl chains (2-decyl-tetradecyl) at both ends.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".