Micellization of ω-Functionalized Poly(styrene-<i>b</i>-isoprene) Copolymers in <i>n</i>-Decane

Pispas, Stergios; Allorio, Serena; Hadjichristidis, Nikos; Mays, Jimmy W.

doi:10.1021/ma951711y

Cited by 10 publications

(9 citation statements)

References 52 publications

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“…The plots were linear with negative slopes, meaning that K d < 0. Similar results were also obtained in other studies of micellization or aggregation phenomena − and are associated with the low A 2 values observed for these systems. The existence of negative K d values implies the presence of strong intermicellar attractive forces, resulting in small excluded volumes and, consequently, in low A 2 values.…”

Section: Resultssupporting

confidence: 91%

Micellization of Model Graft Copolymers in Dilute Solution

et al. 1997

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The micellization behaviors of graft copolymers consisting of polystyrene, PSt, backbones and poly(tert-butyl methacrylate), PtBuMA, or poly(methacrylic acid), PMAA, branches were studied in dilute solutions by low angle laser light scattering, LALLS, viscometry, and dynamic light scattering, DLS. tert-Amyl alcohol, a selective solvent for the PtBuMA branches, and tetrahydrofuran, THF, a selective solvent for the PSt backbones, were used to promote the formation of micelles from the PSt-g-PtBuMA and PSt-g-PMAA graft copolymers, respectively. Low aggregation numbers were obtained in all cases due to the specific architectural characteristics of the samples. Aggregation numbers were dependent on the type of the component (backbone or branches) that was insoluble in the selective solvent. The formation of micelles from the PSt-g-PtBuMA graft copolymers in tert-amyl alcohol is evidenced by the appearance of large and rather loose aggregates at a certain concentration range. This kind of behavior was not observed for the micelles formed from the graft copolymers with PMAA branches in THF. Stable and compact structures were obtained in this case, with their hydrodynamic behavior resembling that of hard spheres.

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Section: Resultssupporting

confidence: 91%

Micellization of Model Graft Copolymers in Dilute Solution

et al. 1997

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“…These elongated structures may be rather loose and the developed shear forces in a capillary tube can disrupt them, provoking stable aggregates with lower viscosities and R v /R h ratios, as observed in the present and several associated systems. [39,41,42,54] Ellipsoids as disks and cylindrical rods are elongated shapes. [19,53] A cylindrical rod with length l and base diameter d can be related with the ratio R g /R h by Equation (9):…”

Section: Solution Properties Of Ps 12 Paa 12 Star Copolymermentioning

confidence: 99%

“…A diblock copolymer with a relatively short ionic segment will form micelles with short hydrophilic corona, known as "crew-cut" micelles, [31] while star-like micelles are formed when the ionic segment is relatively long. [33 -35] In recent years complex architectures such as heteroarm star, [36 -40] functionalized star [41,42] and super H [43] copolymers have attracted attention, in order to investigate the effect of macromolecular architecture on the association phenomena. Recently we have reported results dealing with the aggregation of heteroarm star copolymers in selective solvents.…”

Section: Introductionmentioning

confidence: 99%

Aggregation Behavior of Polystyrene/Poly(acrylic acid) Heteroarm Star Copolymers in 1,4-Dioxane and Aqueous Media

Voulgaris

Tsitsilianis²

2001

Macromol. Chem. Phys.

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Ionic heteroarm star copolymers bearing polystyrene (PS) and poly(acrylic acid) (PAA) arms (PSnPAAn) were prepared by quantitative hydrolysis of the poly(tert‐butyl acrylate) (PtBA) arms of the corresponding PSnPtBAn star copolymer. The aggregation properties of these copolymers were studied in various solvents. In 1,4‐dioxane PS12PAA12 (with nearly symmetrical PS and PAA arms) forms reverse micelles of low aggregation number (Nagg) and spherical morphology. In an 80 : 20 (v/v) 1,4‐dioxane/water mixture these micelles are transformed to regular micelles with an unexpectedly high Nagg and an elongated rod‐like structure. An abnormal behavior was observed in aqueous solutions of charged PS24PANa24 (with asymmetrical PS and PAA arms, WPS = 19 wt.‐%) at low concentrations. A non‐equilibrium physical gel is formed, characterized by a very high viscosity and an elastic response upon oscillatory shearing.

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“…More than a decade ago, the charged moieties at the ω- or α,ω-ends of polystyrene- b -polyisoprene (PS- b -PI) block copolymers were shown to modify microphase separation behavior, as reported by Wiesner et al − and Hadjichristidis et al − More recently, Park et al reported more radical changes in the morphology, thermal, viscoelastic, and ion transport properties of block copolymers via the end-group variation of poly(ethylene oxide) (PEO) blocks in PS- b -PEO, , which could be further strengthened by attaching di-end-functional moieties . Intriguingly, the changes in the polymer properties driven by the terminal groups were much less obvious for PEO homopolymers, indicating that the relationship between the properties and end-group identity is affected by their confinement.…”

Section: Introductionmentioning

confidence: 95%

End-Group Chemistry and Junction Chemistry in Polymer Science: Past, Present, and Future

2020

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The current goal in functional polymeric material research is the preparation of polymers with high-fidelity nanoscale self-assembled structures and advanced functionality. Thus, recent research efforts have focused on linking chemistry for the development of tailor-made polymers with desired properties. The design of α- or ω-functionalized telechelic polymers with strongly associative interactions is connected to their unique supramolecular self-assembly behavior in homopolymers and blends. In addition, the end-group modification of block copolymers has shown to alter the polymer morphology radically, resulting in unprecedented property changes arising from confinement effects. This is fascinating because the content of terminal moieties is small compared to that of macromolecular polymer backbones. As an emerging theme in polymer designs and end-group chemistry, the controlled synthesis of polymers with complex architectures and functional linkages has been performed extensively in the past few decades. However, the effects of this linkage on the resultant polymer properties remain elusive and thus will be an important research topic in polymer science in the near future.

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Micellization of ω-Functionalized Poly(styrene-b-isoprene) Copolymers in n-Decane

Cited by 10 publications

References 52 publications

Micellization of Model Graft Copolymers in Dilute Solution

Micellization of Model Graft Copolymers in Dilute Solution

Aggregation Behavior of Polystyrene/Poly(acrylic acid) Heteroarm Star Copolymers in 1,4-Dioxane and Aqueous Media

End-Group Chemistry and Junction Chemistry in Polymer Science: Past, Present, and Future

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