Electroacoustic and rheological characterization of hydrogel nanocomposites
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Hydrogels have widespread scientific, technological and commodity applications due to their biocompatibility, tuneable porosity and mechanical properties.One promising technique to synthesize hydrogels with desirable physicochemical properties is to embed nanoparticles (NPs) in the gel network, forming hydrogel nanocomposites.Because of the NP crosslinking, hydrogel nanocomposites typically have enhanced mechanical properties, such as high storage and loss moduli and resistance to breaking.This thesis consists of two parts.In the first part, using rheometry, chemically crosslinked hydrogels are studied to characterize NP-hydrogel interactions that modify the bulk mechanical properties.In the second part, electroacoustic spectroscopy is used to investigate microscale interactions between the NPs and the polymer network, and their effect on NP dynamics.Sol-gel transition of chemically crosslinked polyacrylamide (PA) hydrogel was studied and compared to that of PA-silica hydrogel nanocomposites to ascertain effects of silica NPs on gelation dynamics.Silica NPs crosslinked PA to form a viscoelastic solid only in the presence of a small quantity of a chemical crosslinker to crosslink the polymer in the NP interstitial space.The scaling exponents at the gel point did not change in the presence of NPs, consistent with the universality of dynamics at the gel point.To obtain a fundamental understanding into the mechanical enhancement by NPs, the effects of NP size, NP concentration and hydrogel composition on the enhancement were studied.The silica-NP crosslinking furnished a significant storage modulus enhancement, particularly in very weakly chemically crosslinked PA.The loss moduli of the hydrogel nanocomposites were significantly higher than those of the chemically crosslinked gels, reflecting adsorption/desorption and friction at the NP surface.The dynamic electrophoretic mobilities of NPs were measured in polyacrylamide hydrogels using electroacoustic spectroscopy, which is a new tool to non-invasively characterize hydrogel nanocomposites.The mobility of silica NPs was sensitive to NP entrapment, size and charge, as well as to the gel rheology and gelation kinetics.From fitting the theory of Wang and Hill to the mobility data, the electrokinetic parameters, such as the -potential de polyacrylamide en utilisant la spectroscopie lectroacoustique, un nouvel outil non-invasif de caractrisation de nanocomposites d'hydrogel.La mobilit des NPs de silice tait sensible l'emprisonnement des NPs, leur dimensions, leur charge, la rhologie du gel et la glation cintique.En ajustant la thorie de Wang et Hill avec les donnes collectes sur la mobilit des NPs des rsultats, les paramtres lectrocintiques, comme tel que le potentiel- et l'paisseur de la double couche lectrique ont pu tre dtermines.L'influence de l'adsorption du polymre ainsi que la composition de l'hydrogel sur la mobilit de NPs de laponite (ayant de fortes interactions avec le PA) et NPs de silice (ayant une faible interaction avec le PA) a t examine.L'augmentation de la concentration du polymre a diminu le potentiel- apparent, ce qui est attribu l'adsorption du polymre, alors que la variation de la concentration en agents rticulant chimiques n'a pas modifi les proprits de la double couche lectrique.De plus, en augmentant la concentration d'agent rticulant chimiques, le nombre de chaines de polymres qui taient lies lastiquement aux NPs a diminu.Ces rsultats sont utiles afin d'tablir la composition d'hydrogel dans le but de contrler les interactions NP-hydrogel, ce qui est particulirement vital dans l'administration de mdicaments afin de rguler la vitesse de libration du mdicament.
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.
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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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 it