Polymer stabilisers for temperature-induced dispersion gelation: Versatility and control

Alava, Cristina; Saunders, Brian R.

doi:10.1016/j.jcis.2005.06.027

Cited by 10 publications

(6 citation statements)

References 17 publications

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“…This is probably assisted by the residual copolymer chains in solution which associate at T cp , presumably adsorbing onto sheets, and reinforce the network structure. The mechanism up to this point is comparable to that proposed earlier for temperature-triggered aggregation of PNIPAm copolymer-coated emulsions and latexes . However, in the present case, self-assembled NC sheets are present, which appear to play a significant role in producing gels at much lower values of ϕ solid (ca.…”

Section: Resultssupporting

confidence: 87%

“…The mechanism up to this point is comparable to that proposed earlier for temperature-triggered aggregation of PNIPAm copolymercoated emulsions and latexes. 23 However, in the present case, self-assembled NC sheets are present, which appear to play a significant role in producing gels at much lower values of φ solid (ca. 0.013).…”

Section: Resultsmentioning

confidence: 52%

“…At temperatures greater than this temperature, junctions form and gelation occurs. This mechanism has also been successfully used to explain temperature-triggered gelation of emulsions and latexes. , …”

Section: Introductionmentioning

confidence: 99%

“…This mechanism has also been successfully used to explain temperature-triggered gelation of emulsions and latexes. 22,23 A defining feature of dispersions that exhibit temperature-triggered gelation 22,24,25 is that the C p * value is significantly smaller than that for the parent polymer solution. This is due to attractive interactions between the polymer and the dispersed phase.…”

Section: Introductionmentioning

confidence: 99%

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Temperature-Triggered Gelation of Aqueous Laponite Dispersions Containing a Cationic Poly(N-isopropyl acrylamide) Graft Copolymer

et al. 2008

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In this work, temperature-triggered gelation of aqueous laponite dispersions containing a cationic poly(N-isopropylacrylamide) (PNIPAm) graft copolymer was investigated. The copolymer used was PDMA(+)(30)-g-(PNIPAm(210))(14) [Liu et al. Langmuir 2008, 24, 7099]. DMA(+) is quarternarized N,N-dimethylaminoethyl methacrylate. The presence of small concentrations of laponite enabled temperature-triggered gel formation to occur at low copolymer concentrations (e.g., 1 wt %). Dynamic rheological measurements of the gels showed that they had storage modulus values of up to 400 Pa when the total solid volume fraction (polymer and laponite) was only about 0.02. The storage modulus was dependent on both the temperature and the composition of the dispersion used for preparation. The key component that provided the temperature-triggered gels with their elasticity was found to be self-assembled nanocomposite (NC) sheets. These NC sheets spontaneously formed at room temperature upon addition of laponite to the copolymer solution. The NC sheets had lateral dimensions on the order of hundreds of micrometers and a thickness of a few micrometers. The NC sheets were present within the temperature-triggered gels and formed elastically effective chains. The NC sheets exhibited temperature-triggered contraction with a contraction onset temperature of 27 degrees C. A conceptual model is proposed to qualitatively explain the relationship between gel elasticity and dispersion composition.

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Temperature-Triggered Gelation of Aqueous Laponite Dispersions Containing a Cationic Poly(N-isopropyl acrylamide) Graft Copolymer

et al. 2008

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“…The solution turbidity starts at the cloud point temperature (Cpt) and this can be easily determined experimentally by light transmission measurement. Cloud point temperatures were measured to estimate the LCST for each polymer (Alava and Saunders, 2006) as shown in table 1.…”

Section: Cloud Point Determinationmentioning

confidence: 99%

Star-shaped poly(oligoethylene glycol) copolymer-based gels: Thermo-responsive behaviour and bioapplicability for risedronate intranasal delivery

Soliman

Elmowafy

Casettari

et al. 2018

International Journal of Pharmaceutics

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The aim of this work was to obtain an intranasal delivery system with improved mechanical and mucoadhesive properties that could provide prolonged retention time for the delivery of risedronate (RS). For this, novel in situ forming gels comprising thermo-responsive star-shaped polymers, utilizing either polyethylene glycol methyl ether (PEGMA-ME 188, Mn 188) or polyethylene glycol ethyl ether (PEGMA-EE 246, Mn 246), with polyethylene glycol methyl ether (PEGMA-ME 475, Mn 475), were synthesized and characterized. RS was trapped in the selected gel-forming solutions at a concentration of 0.2% w/v. The pH, rheological properties, in vitro drug release, ex vivo permeation as well as mucoadhesion were also examined. MTT assays were conducted to verify nasal tolerability of the developed formulations. Initial in vivo studies were carried out to evaluate anti-osteoporotic activity in a glucocorticoid induced osteoporosis model in rats. The results showed successful development of thermo-sensitive formulations with favorable mechanical properties at 37 °C, which formed non-irritant, mucoadhesive porous networks, facilitating nasal RS delivery. Moreover, sustained release of RS, augmented permeability and marked anti-osteoporotic efficacy as compared to intranasal (IN) and intravenous (IV) RS solutions were realized. The combined results show that the in situ gels should have promising application as nasal drug delivery systems.

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Engineering Thermoresponsive Emulsions with Branched Copolymer Surfactants

Silva

Rajbanshi

Opoku‐Achampong

et al. 2022

Macro Materials & Eng

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show abstract

Polymer stabilisers for temperature-induced dispersion gelation: Versatility and control

Cited by 10 publications

References 17 publications

Temperature-Triggered Gelation of Aqueous Laponite Dispersions Containing a Cationic Poly(N-isopropyl acrylamide) Graft Copolymer

Temperature-Triggered Gelation of Aqueous Laponite Dispersions Containing a Cationic Poly(N-isopropyl acrylamide) Graft Copolymer

Star-shaped poly(oligoethylene glycol) copolymer-based gels: Thermo-responsive behaviour and bioapplicability for risedronate intranasal delivery

Engineering Thermoresponsive Emulsions with Branched Copolymer Surfactants

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