Nonfouling biomaterials based on polyethylene oxide‐containing amphiphilic triblock copolymers as surface modifying additives: Solid state structure of PEO‐copolymer/polyurethane blends
Bibliographic record
Abstract
Three novel polyethylene oxide-containing amphiphilic triblock copolymers (PEO-PU-PEO) with PEO MWs 550, 2000, and 5000, were blended with a segmented polyurethane (PU). It was expected that the block copolymers would act as surface modifiers to produce surfaces rich in PEO. The solid state properties of the PEO-copolymer/PU blends were studied by infrared spectroscopy, differential scanning calorimetry, and tensile stress-strain measurements. Infrared analysis showed no significant hydrogen bonding between the PEO blocks of the copolymers and the PU matrix. Differential scanning calorimetry data indicated that for copolymer content up to 5 wt % the microphase structure of the blends was indistinguishable from that of the unmodified PU matrix; for copolymer content of 10% or greater, the blends showed phase separated structures. Similarly the tensile stress-strain properties of the blends were essentially the same as those of the matrix up to 5 wt % copolymer. At higher copolymer content, however, the tensile strength decreased with increasing content of the copolymers; for a given copolymer content the change in tensile properties increased with increasing PEO MW. The structures of the 20% blends were also investigated after extraction with toluene (copolymers soluble, matrix insoluble). Bulk compositional change upon extraction was determined by nuclear magnetic resonance spectroscopy. Surface compositional change was studied by X-ray photoelectron spectroscopy and water contact angles. Surface morphology was observed using scanning electron microscopy and atomic force microscopy. It was shown that the copolymers were removed from the blends by extraction and that the extent of removal increased with decreasing MW of the PEO block. After toluene extraction, the blend surfaces showed advancing water contact angle and surface elemental composition similar to those of the PU matrix. However in contrast to the relatively smooth matrix surface, the extracted blend surfaces were "decorated" with lacunae or pits. Consistent with the weight loss trends, the extent of pitting was greater for the copolymers having shorter PEO blocks, suggesting that surface enrichment of the copolymers increased with decreasing MW of the copolymers.
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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".