Adsorption of Poly (ethylene oxide) onto Silica at Different Solids                    Loadings

Bjelopavlic, Mick; Zaman, Abbas A.; Moudgil, Brij M.

doi:10.14356/kona.2000011

Cited by 4 publications

(3 citation statements)

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“…It seemed necessary and relevant to explain the polymer behavior at the silica surface in contact with aqueous solutions. Indeed, under certain conditions vertical jumps or kinks , have been observed on adsorption isotherms of polymers on solid particles such as silica beads in suspension in aqueous solutions. Although they had usually been identified as the signature of surface demixing, little has been done to determine their origin despite the publication of other surface studies carried out either in porous media or in Langmuir films .…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies carried out on similar systems have highlighted how the bulk or surface properties of the system under study can be strongly affected by the structure in solution or on the surface. Most of the practical applications described in the literature have been found from modified or associated PEGs. ,− ,− Oxide suspensions covered with PEGs are often used to adjust the liquid viscosity; , the hydrogen bond plays a crucial role in the solution properties. Here, the PEG under study was single pure PEG 400 adsorbed onto nonporous silica, and surface phase diagrams were determined by adsorption measurements though this method is rather time-consuming and tedious.…”

Section: Introductionmentioning

confidence: 99%

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Polyethylene Glycol Adsorption on Silica: From Bulk Phase Behavior to Surface Phase Diagram

et al. 2007

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A characterization of the bulk-phase diagram from literature data and new NMR and DSC measurements provided us with valuable elements that are helpful for gaining, from aqueous solution, better insight into the surface behavior of polyethylene glycol on Aerosil 200. Adsorption isotherms built further to measurements by a depletion method showed a strong and temperature-dependent variation of the isotherm shape in agreement with the variations of interactions already evidenced in the bulk. In temperature-concentration areas, where water is behaving as a helix-promoting solvent, the finding of positive PEG adsorptions and stairlike isotherms agrees with observations reported in the literature. We identified some of the vertical parts as corresponding to the formation of monolayers of helix-shaped PEG molecules. In poor-solvent zones, adsorptions were null or negative, and the isotherms exhibited oscillations suggesting very different surface behavior. Our data analysis evidenced the presence of a much greater amount of water than in the previous surface states; however, the similar analysis of PEG behavior remains relevant. Indeed, the occurrence of first-order transitions in the surface layer implies some water reorganization, permitting the PEG molecules to move closer to the surface and become helix-shaped to rearrange in a monolayer. The surface phase diagram confirmed this analysis in a very satisfying way.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Polyethylene Glycol Adsorption on Silica: From Bulk Phase Behavior to Surface Phase Diagram

et al. 2007

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“…The computational study of Theeyancheri et al predicted a decrease in the MSD and MSAD slopes for Janus probes propelling with their sticky side forward in a medium containing polymers with sticky monomers. 59 Since adsorption of PEO on SiO 2 is well established, 60,61 we expect that the sticky interactions between the SiO 2 hemisphere of the active JC and the surrounding PEO chains may result in an increased concentration of polymer chains in the vicinity of the JC, thereby introducing a local viscoelastic response in the medium surrounding the particle. As the concentration of PEO in the bulk medium increases, the probability and hence the amount of PEO adsorbed on the silica surface is also expected to increase.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Dynamics of Active SiO₂–Pt Janus Colloids in Dilute Poly(ethylene oxide) Solutions

et al. 2023

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Self-propelled Janus colloids (JCs) have recently gained much attention due to their ability to move autonomously and mimic biological microswimmers. This ability makes them suitable for prospective drug/cargo-delivery applications in microscopic domains. Understanding their dynamics in surroundings doped with macromolecules such as polymers is crucial, as most of the target application media are complex in nature. In this study, we investigate the selfdiffusiophoretic motion of hydrogen peroxide-fuelled SiO 2 −Pt JCs in the presence of dilute amounts of poly(ethylene oxide) (PEO). Despite the addition of PEO chains producing a Newtonian behavior with negligible increase in viscosity, the ballistic movement and rotational fluctuations of active JCs are observed to be significantly suppressed. With an increase in the polymer concentration, this leads to a transition from smooth to jittery to cage-hopping to the arrested motion of active JCs. We further propose that the anisotropic interaction of the polymers with the JC increases the "local drag" of the medium, resulting in the unusual impediment of the active motion.

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Characterization of the interaction of poly(ethylene oxide) with nanosize fumed silica: Surface effects on crystallization

Ding

Maitra

Wunder

2003

J Polym Sci B Polym Phys

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Poly(ethylene oxide) (PEO) of 4600 molar mass (PEO‐4600) was crystallized from methanol in the presence of hydrophilic fumed silicas (A380, A200, and OX50) with nominal surface areas of 380, 200, and 50 m2/g and a hydrophobic fumed silica (R812s) modified with methyl groups. The composites were characterized by thermogravimetric analysis and differential scanning calorimetry. The inhibition of crystallization and the tendency for chain reorganization after melting were in the order of A380 > A200 > OX50 > R812s, respectively, that is, both were least for the hydrophobic silica and increased with increasing specific surface area for the hydrophilic silica. The interaction of PEO with the silica increased in the melt state as compared with the solution‐cast samples, resulting in enhanced suppression of crystallization. The following took place at a high silica content: (1) crystallization occurred at crystallization temperatures [Tc < Tc (bulk)], suggesting that the silica inhibited crystallization; (2) crystallites with melt temperatures [Tm < Tm (bulk)] were observed, indictive of smaller and/or less perfect crystals; and (3) melt entropies [ΔSm (surface) < ΔSm (bulk)] suggested that the interaction of surface silanols, SisOH, with PEO decreased both the melt entropy and crystallite size/perfection. Crystallinity was observed in solution‐cast composites when there were greater than ∼0.03 PEO molecules/nm2 for native and ∼0.01 PEO molecules/nm2 for methylated fumed silica, similar to reported plateau equilibrium adsorption values from methanol. These results were consistent with a model in which PEO interacted more strongly with native fumed silica as compared with hydrophobically modified silica because of hydrogen bonding of the ether oxygens of PEO with the acidic silanols, preventing chain mobility and crystallization. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1978–1993, 2003

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Adsorption of Poly (ethylene oxide) onto Silica at Different Solids Loadings

Abstract: The adsorption of poly (ethylene oxide) (PEO)

Cited by 4 publications

References 4 publications

Polyethylene Glycol Adsorption on Silica: From Bulk Phase Behavior to Surface Phase Diagram

Polyethylene Glycol Adsorption on Silica: From Bulk Phase Behavior to Surface Phase Diagram

Dynamics of Active SiO₂–Pt Janus Colloids in Dilute Poly(ethylene oxide) Solutions

Characterization of the interaction of poly(ethylene oxide) with nanosize fumed silica: Surface effects on crystallization

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Adsorption of Poly (ethylene oxide) onto Silica at Different Solids Loadings

Abstract: The adsorption of poly (ethylene oxide) (PEO)

Cited by 4 publications

References 4 publications

Polyethylene Glycol Adsorption on Silica: From Bulk Phase Behavior to Surface Phase Diagram

Polyethylene Glycol Adsorption on Silica: From Bulk Phase Behavior to Surface Phase Diagram

Dynamics of Active SiO2–Pt Janus Colloids in Dilute Poly(ethylene oxide) Solutions

Characterization of the interaction of poly(ethylene oxide) with nanosize fumed silica: Surface effects on crystallization

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Dynamics of Active SiO₂–Pt Janus Colloids in Dilute Poly(ethylene oxide) Solutions