A study of temperature-induced aggregation of responsive comb copolymers in aqueous solution

Koh, Andrew Yew Chiang; Heenan, Richard K.; Saunders, Brian R.

doi:10.1039/b211294a

Cited by 12 publications

(9 citation statements)

References 20 publications

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“…4 shows transmittance vs. temperature curves for all the NPGs with different contents of monomers and the transmissions decreased above the LCST obviously. It was because of chain collapse and aggregation in solution, as has been established for NPGs [37]. These data show that all the NPGs had very sensitive and different transmittance changes in a distinctly narrow temperature range.…”

Section: Effect Of Monomer Concentration On Lcstsupporting

confidence: 67%

Studies on properties of temperature-sensitive amphiphilic copolymer-modified PVDF ultrafiltration membrane

Shen¹,

Xiao

Liu³

et al. 2014

Desalination and Water Treatment

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A B S T R A C TA series of temperature-sensitive poly-N-isopropyl acrylamide-co-polyethylene glycol methyl methacrylates (NPGs) containing different mass ratios of N-isopropyl acrylamide and poly(ethylene glycol) methacrylate (PEGMA) were synthesized successfully. Each of the NPGs were blended with poly(vinylidene fluoride) to prepare ultrafiltration membranes which have temperature sensitivity and higher hydrophilicity. Both the properties were found to be dependent on the synthesis reaction conditions of NPGs. The morphologies of the membranes were characterized by scanning electron microscopy. With PEGMA content increasing in NPGs, the structures of pure membrane and blended membranes changed from typical asymmetric morphology with short finger-like pores to macrovoid. With the temperature or PEGMA content increasing, the water fluxes of both increased obviously. For example, when the PEGMA content was the highest, the water flux of the blended membrane increased up to 3.2 times compared with pure membrane at 55˚C. Bovine serum albumin (67 kDa), polyethylene glycol (50 kDa), polyethylene glycol (20 kDa), and rejection measurements of the blended membrane (e.g. M 3 ) were conducted in this work. The rejection of the same membrane to different molecular weight substances changed greatly with temperature changing from 10˚C to 60˚C, which made it possible to separate substances by controlling temperature.

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Section: Effect Of Monomer Concentration On Lcstsupporting

confidence: 67%

Studies on properties of temperature-sensitive amphiphilic copolymer-modified PVDF ultrafiltration membrane

Shen¹,

Xiao

Liu³

et al. 2014

Desalination and Water Treatment

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“…Copolymer Preparation. The synthetic method used to prepare poly(NIPAM- co -PEGMa) has been described in detail elsewhere . It is briefly described here.…”

Section: Methodsmentioning

confidence: 99%

“…Physical Measurements. Turbidity measurements were performed using D 2 O as solvent and are described fully elsewhere . Optical microscopy data were collected using an Olympus H30 microscope.…”

Section: Methodsmentioning

confidence: 99%

Small-Angle Neutron Scattering Study of Temperature-Induced Emulsion Gelation: the Role of Sticky Microgel Particles

Koh

Saunders

2005

Langmuir

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In this work, small-angle neutron scattering (SANS) is used to probe the structural transformations that accompany temperature-induced gelation of emulsions stabilized by a temperature-responsive polymer. The latter is poly(NIPAM-co-PEGMa) (N-isopropylacrylamide and poly(ethyleneglycol) methacrylate) and contains 86 mol% NIPAM. Turbidity measurements revealed that poly(NIPAM-co-PEGMa) has a lower critical solution temperature (T(LCST)) of 36.5 degrees C in D(2)O. Aqueous polymer solutions were used to prepare perfluorodecalin-in-water emulsions (average droplet size of 6.9 mum). These emulsions formed gels at 50 degrees C. SANS measurements were performed on the poly(NIPAM-co-PEGMa) solutions and emulsions as a function of temperature. The emulsion was also prepared using a D2O/H2O mixture containing 72 vol% D2O in order to make scattering from the droplets negligible (on-contrast). The SANS data were analyzed using a combination of Porod and Ornstein-Zernike form factors. The results showed that the correlation length (xi) of the polymer scaled as xi approximately phi(p)(-0.68) at 32 degrees C, where phi(p) is the polymer volume fraction. The xi value increased for all systems as the temperature increased, which was attributed to a spinodal transition. At temperatures greater than T(LCST), the polymer solution changed to a polymer dispersion of poly(NIPAM-co-PEGMa) aggregates. The aggregates have features that are similar to microgel particles. The average size of these particles was estimated as 160-170 nm. The particles are "sticky" and are gel-forming. The on-contrast experiments performed using the emulsion indicated that the interfacial polymer chains condensed to give a relatively thick polymer layer at the perfluorodecalin-water interface at 50 degrees C. The gelled emulsions appear to consist of perfluorodecalin droplets with an encapsulating layer of collapsed polymer to which sticky microgel particles are adsorbed. The latter act as a "glue" between coated droplets in the emulsion gel.

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“…Consequently, the high polydispersity of the poly(NIPAM-co-PEGMa) is not of significance for this study, which focusses on gelation behaviour. It is useful to note that poly(NIPAM-co-PEGMa) chains of this composition have been investigated using SANS by Koh and Saunders [15] and found to exist as isolated coils in solution at room temperature with a radius of gyration of ca. 8 nm.…”

Section: Responsive Polymer Stabiliser: Characterisation and Cloud Pomentioning

confidence: 99%

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

Alava

Saunders

2006

Journal of Colloid and Interface Science

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A study of temperature-induced aggregation of responsive comb copolymers in aqueous solution

Cited by 12 publications

References 20 publications

Studies on properties of temperature-sensitive amphiphilic copolymer-modified PVDF ultrafiltration membrane

Studies on properties of temperature-sensitive amphiphilic copolymer-modified PVDF ultrafiltration membrane

Small-Angle Neutron Scattering Study of Temperature-Induced Emulsion Gelation: the Role of Sticky Microgel Particles

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

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