Nearly Monodisperse Silica\nMicroparticles Form in\nSilicone (Pre)elastomer Mixtures
Bibliographic record
Abstract
The formation of silica from a tetraalkoxysilane in a\nsol–gel\nprocess usually requires a highly polar, typically aqueous, medium\nthat aids in the hydrolysis of the silane and leads to electrostatic\nstabilization of the growing silica particles. Formation of such silica\nparticles in a hydrophobic medium is much more challenging. We report\nthe formation of silica microspheres within silicone oils (hydroxy-terminated\npoly(dimethylsiloxane), HO-PDMS) during elastomer cure using atmospheric\nhumidity in a one-pot and one-step synthesis. Using tetraethyl orthosilicate\n(TEOS) as both cross-linker and silica precursor, and aminopropyl-terminated\ndimethylsiloxane oligomer (<b>AT-PDMS</b>) as a catalytic surfactant,\nsilica particles of low polydispersity formed near or at the air interface\nof the elastomer: the presence of a hydrophilic polymer, poly(ethylene\nglycol) (PEG), had an indirect effect on the particle formation, as\nit assisted with water transmission into the system, which resulted\nin particle formation over a wider range of parameters and facilitated\nsilicone elastomer cure further away from the air interface. Depending\non the relative humidity during cure, the sizes of particles presenting\nat the air interface varied from ∼6–7 μm under\nambient conditions (20–30%RH) to ∼7–9 μm\nat high relative humidity (90% RH). The origin of the controlled particle\nsynthesis is ascribed to the relative solubility of the catalyst and\nthe efficiency of water permeation through the silicone matrix. <b>AT-PDMS</b> preferentially migrates to the air interface, as shown\nby ninhydrin staining, where it both catalyzes alkoxysilane hydrolysis\nand condensation, and stabilizes the growing silica particles prior\nto aggregation. Since reactions in the presence of this catalyst are\nslow, TEOS can migrate from within the pre-elastomer body to the interface\nfaster than water can penetrate the silicone, such that the main locus\nof hydrolysis/condensation leading both to silica formation and elastomer\ncross-linking is at the air interface.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.099 | 0.009 |
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; both teacher heads agree on what is shown here.
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".