Properties of copolymers composed of one poly-ethylene-oxide and one polystyrene block

Lotz, Bernard; Kovacs, A. J.; Bassett, G. A.; Keller, A.

doi:10.1007/bf01500629

Cited by 219 publications

(189 citation statements)

References 14 publications

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“…These major fronts constituted four sides of square of ideal and monolayer single crystal. This was in accordance with those that have been reported for homo-PEG and copolymer single crystals having PEG as crystalline substrate up to now [19,42,57,58].…”

Section: Homopolymer/block Copolymer Single-co-crystalssupporting

confidence: 93%

Fine fibrillar and rectangular/hexagonal ordered grains of poly(3-hexyl thiophene) and poly(ethylene glycol) developed by seeding technique

et al. 2016

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The fibrillar poly(3-hexyl thiophene) single crystals were prepared from dilute solutions of toluene, xylene, and anisole (0.01 wt%), and were investigated from the perspective of structural properties. Next, the rectangular and hexagonal poly(ethylene glycol) single crystals were developed from the dilute solutions and molten thin polymer films. The developing methodology used for all growth systems was self-seeding. The dimensions of fibrillar and rectangular/hexagonal single crystals ranged from several nanometers to some microns. Random single-co-crystals were also grown from dilute solution (0.018 wt% in amyl acetate) of crystalline-amorphous diblock copolymers and homopolymers. The small-angle X-ray scattering, grazing incidence wide-angle X-ray scattering, and atomic force microscopy analyses were employed to characterize prepared grained samples. The incident X-ray experiments demonstrated highly ordered and lamellar crystalline structures.

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Section: Homopolymer/block Copolymer Single-co-crystalssupporting

confidence: 93%

Fine fibrillar and rectangular/hexagonal ordered grains of poly(3-hexyl thiophene) and poly(ethylene glycol) developed by seeding technique

et al. 2016

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“…The preferential hydrolysis of pegylated chains was also corroborated by the 1 H NMR spectra (not shown) of the residue extracted from the hydrolytic degradation medium after 72 h of exposure, which indicated a PEG/HD ratio higher than 15:1. Furthermore, lamellar crystals with the characteristic morphology of polyethylene glycol lamellae [37,38] were recovered after evaporation of the degradation medium. Specifically, Figure 6b shows typical square lamellae of PEG and the corresponding electron diffraction pattern with intense 120 reflections at 0.462 nm.…”

Section: Hydrolitic Degradation Ofmentioning

confidence: 99%

Nanospheres and nanocapsules of amphiphilic copolymers constituted by methoxypolyethylene glycol cyanoacrylate and hexadecyl cyanoacrylate units

Valente¹,

Valle²,

Casas³

et al. 2013

Express Polym. Lett.

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Nanospheres and nanocapsules of an amphiphilic copolymer having methylated polyethylene glycol and hexadecyl lateral groups were prepared by the solvent displacement method and using confined impinging jet mixers. Degradation, thermal properties and crystalline structure were investigated. Interestingly, pegylated chains hydrolyzed through ester bond cleavage, whereas the more hydrophobic hexadecyl ester groups were resistant to degradation in aqueous media. The copolymer crystallized from the melt, giving rise to spherulites with a negative birefringence and domains corresponding to crystallization of the different lateral groups. Size distribution and morphology of nanoparticles were mainly evaluated by electron microscopy. Nanocapsules were characterized by a stable membrane with a thickness close to 5 nm that allowed efficient encapsulation of a triglyceride oil. Triclosan was selected as an example of a hydrophobic drug to be loaded in both nanospheres and nanocapsules. The release behavior of these dosage forms was clearly different. Thus, the Burst effect was practically suppressed when using nanocapsules; in addition, these showed a sustained, controlled release over a greater time period. Antimicrobial activity of triclosan loaded nanospheres and nanocapsules was evaluated using Gram-negative and Gram-positive bacteria. The former were highly sensitive to the released triclosan whereas the latter strongly depended on the number of particles in the culture medium

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“…1 The earliest examples involved planar structures, 2 but recent attention has turned to block copolymers that form elongated fiber-like structures. 3,4 The first examples of rodlike core-crystalline micelles were reported almost 20 years ago for poly(ferrocenyldimethylsilane) (PFS) diblock copolymers.…”

Section: Introductionmentioning

confidence: 99%

Lateral Growth of 1D Core-Crystalline Micelles upon Annealing in Solution

et al. 2016

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The emergence of one-dimensional (1D) micelles obtained from the crystallization driven self-assembly (CDSA) in solution of crystalline-coil block copolymers has opened the door to the fabrication of a variety of sophisticated structures. While the development of these fascinating nanomaterials is blossoming, there is very little fundamental work dedicated to understanding the morphological evolution of these 1D micelles in solution. Here, using a combination of transmission electron microscopy, electron tomography, and static and dynamic light scattering, we studied the effect of annealing on a colloidal suspension of 1D micelle fragments formed by the self-assembly of a crystalline-coil poly(ferrocenyldimethylsilane)-block-poly(isoprene) (PFS-b-PI) block copolymer in decane, a solvent selective for PI. We are particularly interested in studying the evolution of the rectangular cross-section of the crystalline core of these micelle fragments. By electron tomography, we observed that the shorter dimension of the cross-section became even thinner upon annealing at elevated temperatures, while the longer dimension increased. In parallel, we observed an increase in packing density of the crystalline block as the fragments were annealed at temperatures above 60 °C. From these results, we concluded that annealing the micelle fragments induces a thinning of the crystalline core coupled with a lateral growth.

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Properties of copolymers composed of one poly-ethylene-oxide and one polystyrene block

Cited by 219 publications

References 14 publications

Fine fibrillar and rectangular/hexagonal ordered grains of poly(3-hexyl thiophene) and poly(ethylene glycol) developed by seeding technique

Fine fibrillar and rectangular/hexagonal ordered grains of poly(3-hexyl thiophene) and poly(ethylene glycol) developed by seeding technique

Nanospheres and nanocapsules of amphiphilic copolymers constituted by methoxypolyethylene glycol cyanoacrylate and hexadecyl cyanoacrylate units

Lateral Growth of 1D Core-Crystalline Micelles upon Annealing in Solution

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