Thermo-responsiveness of poly(-diethylacrylamide) polymers at the air–water interface: The effect of a hydrophobic block

Silva, Amélia M. Gonçalves da; Lopes, S.I.C.; Brogueira, P.; Prazeres, Telmo J. V.; Beija, Mariana; Martinho, J. M. G.

doi:10.1016/j.jcis.2008.08.011

Cited by 30 publications

(11 citation statements)

References 57 publications

(65 reference statements)

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“…Later, work on poly( N -alkylacrylamide)s showed that increasing the pendant alkyl group from one to three carbon atoms increased the KHI performance (Table , Figure ). This improvement also correlated with a decrease in the polymer cloud point. − …”

Section: Review Of Previous Work On Khismentioning

confidence: 78%

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Does the Cloud Point Temperature of a Polymer Correlate with Its Kinetic Hydrate Inhibitor Performance?

Dirdal

Kelland

2019

Energy Fuels

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Most polymers used in commercial kinetic hydrate inhibitor (KHI) formulations show thermoresponsive behavior in aqueous solution. This means that they exhibit a cloud point (or lower critical solution temperature) which is often low and not far above the equilibrium temperature for gas hydrate formation. For example, poly(N-vinyl caprolactam) has a cloud point of about 30−40 °C and poly(N-isopropylmethacrylamide) has a cloud point of about 35−45 °C depending on the molecular weight and method of polymerization. This report is divided into two parts. First, we review previous KHI studies and show that low cloud point is a useful factor, but not the most critical factor, to be considered within a specific class of polymers in designing a high-performance KHI. This statement is supported in the second part of this report, which is an experimental KHI study. In this study, we present results of KHI tests for a natural gas/deionized water structure II gas hydrate-forming system using low cloud point polymers with a variety of different shapes, molecular weights, functional groups, and sizes of pendant hydrophobic groups. We conclude that the low cloud point, near the hydrate formation temperature, appears to be useful for high KHI efficacy of a polymer but only if certain criteria are met. These include low molecular weight, pendant hydrophobic groups of an optimal size close to the polymer backbone, and the correct hydrophilic functional groups. Possible theories as to why low cloud point for a KHI polymer can be beneficial are discussed, as well as some guidelines for the KHI polymer design.

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Section: Review Of Previous Work On Khismentioning

confidence: 78%

“…By increasing the temperature above T cl , the amide–water hydrogen bonds disrupt and the hydrophobic interactions increase. This promotes the release of the bound and structured water and the swollen conformation collapses, causing aggregation of polymer strands …”

Section: Introductionmentioning

confidence: 99%

Does the Cloud Point Temperature of a Polymer Correlate with Its Kinetic Hydrate Inhibitor Performance?

Dirdal

Kelland

2019

Energy Fuels

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“…The critical temperature of PNIPAM is close to the body temperature of human beings, and hence, it has potential applications in drug release and drug carriers. , Graziano pointed out that the coil- to -globule collapse of PNIPAM above the Θ-point temperature is a first-order entropy-driven phase transition . In recent years, the aggregation behaviors of block copolymers containing PNIPAM at the air/water interface have attracted much attention. − Liu et al explored the interfacial conformation properties of PS- b -PNIPAM and found that the dependencies of surface pressure on temperature and compression rate were strongly influenced by the loop or trail conformations of PNIPAM blocks; however, it has no dependency when they took the train conformation …”

Section: Introductionmentioning

confidence: 99%

Effects of Subphase pH and Temperature on the Aggregation Behavior of Poly(lauryl acrylate)-block-poly(N-isopropylacrylamide) at the Air/Water Interface

et al. 2019

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Effects of subphase pH and temperature on the aggregation behavior of a thermosensitive amphiphilic diblock copolymer poly(lauryl acrylate)-block-poly(N-isopropylacrylamide) (PLA-b-PNIPAM) at the air/water interface and the morphologies of its Langmuir–Blodgett (LB) films were characterized with the Langmuir film balance technique and atomic force microscopy, respectively. The surface pressure–molecular area isotherms shift positively with the increase of subphase pH, and there exist two quasi-plateaus under acidic condition but only one under neutral or alkaline conditions. The lower and upper plateaus under acidic condition are attributed to immersion into water for the protonated amide groups and the rest of PNIPAM blocks, respectively. The plateau pressures gradually decrease with the elevation of temperature due to promotion of protonation and solubility of PNIPAM blocks. On the contrary, those under neutral and alkaline conditions gradually increase but exhibit a lower critical solution temperature behavior which is consistent with that of PNIPAM-containing polymers in aqueous solutions. The initial LB films of PLA-b-PNIPAM transferred from different subphases exhibit tiny isolated circular micelles which coalesce and transform into large dense ones upon compression. Furthermore, PLA cores usually coalesce with the elevation of temperature due to the increased molecular thermal mobility as a result of their low glass transition temperature.

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“…Compression and expansion isotherms give information on the spatial demands of adsorbed polymers along with their ability to stabilize the interface. In previous studies amphiphilic diblock copolymers, [4][5][6] colloidal particles like microgels, 7,8 thermoresponsive polymers 9,10 and star-shaped molecules have been investigated. [11][12][13][14] Interfaces also operated as templates for complexation between different components.…”

Section: Introductionmentioning

confidence: 99%

Interface-enforced complexation between copolymer blocks

Steinschulte

Draber

et al. 2015

Soft Matter

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Binary diblock copolymers and corresponding ternary miktoarm stars are studied at oil-water interfaces. All polymers contain oil-soluble poly(propylene oxide) PPO, water-soluble poly(dimethylaminoethyl methacrylate) PDMAEMA and/or poly(ethylene oxide) PEO. The features of their Langmuir compression isotherms are well related to the ones of the corresponding homopolymers. Within the Langmuir-trough, PEO-b-PPO acts as the most effective amphiphile compared to the other PPO-containing copolymers. In contrast, the compression isotherms show a complexation of PPO and PDMAEMA for PPO-b-PDMAEMA and the star, reducing their overall amphiphilicity. Such complex formation between the blocks of PPO-b-PDMAEMA is prevented in bulk water but facilitated at the interface. The weakly-interacting blocks of PPO-b-PDMAEMA form a complex due to their enhanced proximity in such confined environments. Scanning force microscopy and Monte Carlo simulations with varying confinement support our results, which are regarded as compliant with the mathematical random walk theorem by Pólya. Finally, the results are expected to be of relevance for e.g. emulsion formulation and macromolecular engineering.

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Thermo-responsiveness of poly(-diethylacrylamide) polymers at the air–water interface: The effect of a hydrophobic block

Cited by 30 publications

References 57 publications

Does the Cloud Point Temperature of a Polymer Correlate with Its Kinetic Hydrate Inhibitor Performance?

Does the Cloud Point Temperature of a Polymer Correlate with Its Kinetic Hydrate Inhibitor Performance?

Effects of Subphase pH and Temperature on the Aggregation Behavior of Poly(lauryl acrylate)-block-poly(N-isopropylacrylamide) at the Air/Water Interface

Interface-enforced complexation between copolymer blocks

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