Polymer architecture dictates thermoreversible gelation in engineered emulsions stabilised with branched copolymer surfactants

Rajbanshi, A.; Silva, Marcelo da; Murnane, Darragh; Porcar, Lionel; Dreiss, Cécile A.; Cook, Michael T.

doi:10.1039/d2py00876a

Cited by 6 publications

(13 citation statements)

References 35 publications

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“…1i). A library of 4 BCS were synthesised and their identities confirmed by 1 H NMR, in accordance with prior studies, 20 and GPC (Fig. 1ii, iii).…”

Section: Resultssupporting

confidence: 54%

“…The oblate geometry is attributed to steric constraints from the branched structure not allowing it to take the required curvature to permit the thermodynamically-preferred spherical morphology often seem in linear micellar systems. 20 In all systems both polar and equatorial radii of the BCS aggregates increased upon heating from 20–45 °C. This is attributed to the increased hydrophobicity of the poly(DEGMA) component of the BCS undergoing LCST transition over this range, driving nanostructural rearrangements for example the aggregation of smaller aggregates into larger ones due to reduced stability on heating.…”

Section: Resultsmentioning

confidence: 89%

“…1iv, where the DEGMA and PEGMA copolymerisation will lead to a comb-polymer like structure with a poly(DEGMA) backbone and PEG pendants from the PEGMA inclusion plus dodecyl-end groups from DDT. 20,34,35 EGDMA induces branching in these comb-like systems. It has previously been found that increased M n favours thermoresponsive gel formation in emulsion systems.…”

Section: Synthesis Of Bcs Librarymentioning

confidence: 97%

“…It has previously been found that increased M n favours thermoresponsive gel formation in emulsion systems. 20…”

Section: Synthesis Of Bcs Librarymentioning

confidence: 99%

“…Recently, branched copolymer surfactants containing thermoresponsive components with a lower critical solution temperature (LCST) have been shown to form emulsions with sol-gel transition upon heating. [19][20][21] The advantage of this system is that the BCS, unlike many block copolymer architectures, may be produced in a single pot under scalable conditions using the ''Strathclyde approach'', 22 simply requiring the monomers and initiators to undergo nitrogen purge and heating in ethanol, a sustainable solvent. 23,24 The synthetic approach allows control of many factors in the thermoresponsive BCS, which is composed of an LCST-imparting monomer, poly(ethylene glycol)methacrylate (PEGMA); ethylene glycol dimethacrylate (EGDMA), as a crosslinker to induce branching, and dodecanethiol (DDT), as a chain transfer agent to impart C12 terminal groups.…”

Section: Introductionmentioning

confidence: 99%

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Branched copolymer surfactants impart thermoreversible gelation to LAPONITE® gels

Rajbanshi,

Da Silva,

Mahmoudi

et al. 2024

Soft Matter

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“…1i). A library of 4 BCS were synthesised and their identities confirmed by 1 H NMR, in accordance with prior studies, 20 and GPC (Fig. 1ii, iii).…”

Section: Resultssupporting

confidence: 54%

Section: Resultsmentioning

confidence: 89%

Section: Synthesis Of Bcs Librarymentioning

confidence: 97%

“…It has previously been found that increased M n favours thermoresponsive gel formation in emulsion systems. 20…”

Section: Synthesis Of Bcs Librarymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Branched copolymer surfactants impart thermoreversible gelation to LAPONITE® gels

Rajbanshi,

Da Silva,

Mahmoudi

et al. 2024

Soft Matter

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Branched Copolymer Surfactants as Versatile Templates for Responsive Emulsifiers with Bespoke Temperature‐Triggered Emulsion‐Breaking or Gelation

Rajbanshi,

Alves da Silva,

Haslett

et al. 2023

Adv Materials Inter

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It has been found that the thermoresponsive behavior of emulsions stabilized by block copolymer surfactants (BCSs) can induce either gelation or emulsion break‐up with mild temperature changes. A hydrophilic, steric‐stabilizing component of the BCS, polyethylene glycol methacrylate (PEGMA), is crucial to control the thermoresponsive behavior of the emulsions: longer PEG chains (950 g mol−1) lead to thermoregulation, whereas shorter PEGM chains (500 or 300 g mol−1) lead to emulsion break‐up upon mild heating. Additionally, the relative abundance of PEGMA to the thermoresponsive component in the BCS controls the gelation temperature of BCS‐stabilized emulsions. Small‐angle neutron scattering and transmission electron microscopy reveal that the BCS forms oblate ellipsoids which grow anisotropically with temperature. In samples that form a gel, there is evidence that these nano‐objects form supra‐colloidal structures, which are responsible for the gel mesophase formation. An optimal BCS can form emulsions that transition from a liquid to gel state when warmed above 32 °C. This makes the system ideal for in situ gelation upon contact with the body. Overall, this study highlights the great potential of BCSs in generating thermoresponsive emulsions for drug delivery and other healthcare applications.

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Stimuli‐Responsive Polymers for Engineered Emulsions

Rajbanshi,

Hilton,

Dreiss

et al. 2024

Macromol. Rapid Commun.

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Emulsions are complex. Dispersing two immiscible phases, thus expanding an interface, requires effort to achieve and the resultant dispersion is thermodynamically unstable, driving the system toward coalescence. Furthermore, physical instabilities, including creaming, arise due to presence of dispersed droplets of different densities to a continuous phase. Emulsions allow the formulation of oils, can act as vehicles to solubilize both hydrophilic and lipophilic molecules, and can be tailored to desirable rheological profiles, including “gel‐like” behavior and shear thinning. The usefulness of emulsions can be further expanded by imparting stimuli‐responsive or “smart” behaviors by inclusion of a stimuli‐responsive emulsifier, polymer or surfactant. This enables manipulation like gelation, breaking, or aggregation, by external triggers such as pH, temperature, or salt concentration changes. This platform generates functional materials for pharmaceuticals, cosmetics, oil recovery, and colloid engineering, combining both smart behaviors and intrinsic benefit of emulsions. However, with increased functionality comes greater complexity. This review focuses on the use of stimuli‐responsive polymers for the generation of smart emulsions, motivated by the great adaptability of polymers for this application and their efficacy as steric stabilizers. Stimuli‐responsive emulsions are described according to the trigger used to provide the reader with an overview of progress in this field.

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Polymer architecture dictates thermoreversible gelation in engineered emulsions stabilised with branched copolymer surfactants

Abstract: Polymer architecture allows control of thermoreversible gelation in branched copolymer-stabilised emulsions.

Cited by 6 publications

References 35 publications

Branched copolymer surfactants impart thermoreversible gelation to LAPONITE® gels

Branched copolymer surfactants impart thermoreversible gelation to LAPONITE® gels

Branched Copolymer Surfactants as Versatile Templates for Responsive Emulsifiers with Bespoke Temperature‐Triggered Emulsion‐Breaking or Gelation

Stimuli‐Responsive Polymers for Engineered Emulsions

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