Two component gels of immiscible blends of biscarbamates (polyurethane model compounds) and poly(ε-caprolactone)
Bibliographic record
Abstract
We describe the gelation of two-component immiscible blends consisting of a set of low molecular weight organogelators and a polymer. We studied the blends of poly(ε-caprolactone) (PCL) and biscarbamates (model compounds for polyurethanes) with two hydrogen bonding motifs separated by a (CH2)6 spacer and symmetrically attached alkyl side chains. Neither PCL nor the biscarbamates form gels with chloroform in their neat forms, although the latter form gels with several other solvents. It is known that PCL does not form a gel by itself in any solvent. Being part of a copolymer or an inclusion complex is necessary for a PCL based gel. In the current work, mixtures of biscarbamates and PCL in chloroform led to phase separation and gelation upon cooling the solution. This gelation behavior depends on the alkyl side chain length of the biscarbamates. Those with alky side chain length below C11 remained soluble and beyond C13 precipitated within the concentration range studied here. Morphological studies showed immiscibility between the biscarbamate and PCL, similar to the case of polyurethanes with PCL as the soft segment. When biscarbamates are minor components in the solvent cast blend films, they form aggregate crystals in the PCL matrix. Upon melting and recrystallizing, PCL forms droplets in the matrix of biscarbamates, although it is the major component. X-ray diffraction studies of the xerogels confirmed the immiscibility of the PCL and biscarbamates and ATR-FTIR spectra showed no change in the hydrogen bonding of these self-assembling biscarbamate molecules. Microscopic studies revealed fibrous morphology of the composite gels, which consist of biscarbamate fibers dispersed in the matrix of PCL fibers. The biscarbamate fibers impregnated in the polymer matrix show the same eavestrough and hollow tube morphology as seen in our previous work (Khanna et al., Langmuir, 2009, 25, 13183).
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".