Solution behaviors and microstructures of PNIPAm-P123-PNIPAm pentablock terpolymers in dilute and concentrated aqueous solutions

Lu, Yu; Chen, Tongquan; Mei, Aixiong; Chen, Tianyou; Ye, Ding; Zhang, Xinghong; Xu, Jun‐Ting; Fan, Zhiqiang; Du, Binyang

doi:10.1039/c3cp50376c

Cited by 36 publications

(40 citation statements)

References 55 publications

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“…While rheology is more sensitive in terms of macromolecular phase behavior, it can also predict the secondary processes on a very short time scale. The rheologically derived LCST value for PNIPAM of 32 °C is in good agreement with the previously reported values …”

Section: Resultssupporting

confidence: 91%

A NIPAM–Zwitterion Copolymer: Rheological Interpretation of the Specific Ion Effect on the LCST

Obiweluozor

GhavamiNejad

Hashmi

et al. 2014

Macro Chemistry & Physics

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The effect of various cations and anions on the ability to shield the electrostatic interaction between charged copolymers containing a non‐ionic moiety (N‐isopropylacrylamide (NIPAM)) is explored. The Hofmeister series, first noted in 1888, ranks the relative influence of ions on the physical behavior of a wide variety of aqueous processes ranging from colloidal assembly to protein folding. The viscoelastic behavior of a poly(NIPAM‐co‐Zw10%) solution as a function of ionic strength in the presence of different ions is rheologically investigated. The obtained copolymer exhibits a thermoresponsive behavior, with tunable lower critical solution temperature (LCST) ranging from 28 to 33 °C. The viscosity change specifically demonstrates the effectiveness of the low‐molecular‐weight ions in weakening the inter‐/intramolecular electrostatic crosslinks among the sulfobetaine chain and in enhancing the hydration of the macromolecule. The effectiveness of the anions follows the Hofmeister series while that of the cations follows the reversed Hofmeister series, as demonstrated by Collins' concept of “matching water affinity,” due to presence of a sulfobetaine group in the chains.

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Section: Resultssupporting

confidence: 91%

A NIPAM–Zwitterion Copolymer: Rheological Interpretation of the Specific Ion Effect on the LCST

Obiweluozor

GhavamiNejad

Hashmi

et al. 2014

Macro Chemistry & Physics

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“…As the temperature was increased to 32 °C, the poly(NIPAAM- co -DMAAPS) solution with a monomer ratio of 100:0 (tube a) exhibited a color/turbidity change. This is consistent with previous studies [ 25 , 50 , 51 ], which reported that poly(NIPAAM) homopolymer chains undergo reversible collapse or swelling in aqueous solutions above or below their transition temperatures/LCSTs, which is approximately 32–34 °C for the co-polymer in the present study. Furthermore, the solutions with the NIPAAM:DMAAPS ratios of 95:5 (tube b), 90:10 (tube c), and 85:15 (tube d) exhibited turbidity at 41, 52, and 70 °C, respectively.…”

Section: Resultssupporting

confidence: 94%

Novel Thermosensitive-co-Zwitterionic Sulfobetaine Gels for Metal Ion Removal: Synthesis and Characterization

Ningrum

Gotoh

Ciptonugroho

et al. 2021

Gels

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Zwitterionic betaine polymers are promising adsorbents for the removal of heavy metal ions from industrial effluents. Although the presence of both negative and positively charged groups imparts them the ability to simultaneously remove cations and anions, intra- and/or inter-chain interactions can significantly reduce their adsorption efficiencies. Therefore, in this study, novel gels based on crosslinked co-polymers of thermosensitive N-isopropylacrylamide (NIPAAM) and zwitterionic sulfobetaine N,N-dimethylacrylamido propyl ammonium propane sulfonate (DMAAPS) were synthesized, characterized, and evaluated for ion removal. Fourier-transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) analyses confirmed the success of the co-polymerization of NIPAAM and DMAAPS to form poly(NIPAAM-co-DMAAPS). The phase transition temperature of the co-polymer increased with increasing DMAAPS content in the co-polymer, indicating temperature-dependent amphiphilic behavior, as evidenced by contact angle measurements. The ion adsorption analyses of the poly(NIPAAM-co-DMAAPS) gels indicated that co-polymerization increased the molecular distance and weakened the interaction between the DMAAPS-charged groups (SO3− and N+), thereby increasing the ion adsorption. The results confirmed that, with a low concentration of DMAAPS in the co-polymer gels (~10%), the maximum amount of Cr3+ ions adsorbed onto the gel was ~58.49% of the sulfonate content in the gel.

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“…21,22 The micellization and thermo-responsive behaviors of numerous PNIPAM-based BCPs have been extensively studied. [23][24][25][26][27][28][29][30] However, in most of the studies only the change in the micelle size without the alteration of the overall micellar morphology is reported. [31][32][33][34] Wu observed a transition of the micellar morphology from wormlike vesicles to spherical vesicles in dioxane/ethanol upon increasing the temperature for a PS-b-PNIPAM formed by hydrogen bonds at the end of both the blocks.…”

Section: Introductionmentioning

confidence: 99%

Effect of local chain deformability on the temperature-induced morphological transitions of polystyrene-b-poly(N-isopropylacrylamide) micelles in aqueous solution

Wang

et al. 2014

Soft Matter

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The effect of temperature on the micellar morphology of two polystyrene-b-poly(N-isopropylacrylamide) (PS-b-PNIPAM) diblock copolymers in an aqueous solution was investigated by dynamic light scattering (DLS) and transmission electron microscopy (TEM). At 25 °C, a mixture of vesicles and spheres are observed for the micelles of PS65-b-PNIPAM108, while PS65-b-PNIPAM360 exhibits mixed cylindrical and spherical micellar morphology. Upon increasing the temperature, the micellar morphology becomes spherical for PS65-b-PNIPAM108 at 60 °C and for PS65-b-PNIPAM360 at 40 °C. Such vesicle-to-sphere and cylinder-to-sphere transitions of micellar morphology are reversible when the micellar solutions are cooled back to 25 °C. However, these temperature-induced morphological transitions of the PS-b-PNIPAM micelles are contrary to the theoretical prediction. Qualitative analysis of the free energy shows that vesicular or cylindrical micelles tend to form at higher temperatures if only the overall volume change of the PNIPAM block is considered. The contradiction between the experimental results and theoretical prediction is interpreted in terms of the local deformability of the PNIPAM chains. At elevated temperatures, the collapsed PNIPAM globules are less deformable and must occupy larger areas at the micellar interface, although the overall volume is smaller at higher temperatures. This will lead to a larger repulsion between the PNIPAM globules and a remarkable increase in the free energy of the corona; thus, the formation of vesicles or cylinders at higher temperatures is prohibited.

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Solution behaviors and microstructures of PNIPAm-P123-PNIPAm pentablock terpolymers in dilute and concentrated aqueous solutions

Cited by 36 publications

References 55 publications

A NIPAM–Zwitterion Copolymer: Rheological Interpretation of the Specific Ion Effect on the LCST

A NIPAM–Zwitterion Copolymer: Rheological Interpretation of the Specific Ion Effect on the LCST

Novel Thermosensitive-co-Zwitterionic Sulfobetaine Gels for Metal Ion Removal: Synthesis and Characterization

Effect of local chain deformability on the temperature-induced morphological transitions of polystyrene-b-poly(N-isopropylacrylamide) micelles in aqueous solution

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