Linear and non-linear triblock terpolymers. Synthesis, self-assembly in selective solvents and in bulk

Hadjichristidis, Nikos; Iatrou, Hermis; Pitsikalis, Marinos; Pispas, Stergios; Avgeropoulos, Apostolos

doi:10.1016/j.progpolymsci.2005.04.001

Cited by 425 publications

(369 citation statements)

References 122 publications

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“…Experimental or simulated realisations of polycontinuous geometries are being explored in a few distinct systems with important differences: Hyde et al have proposed tricontinuous surfaces as a natural candidate for the self-assembly of star-shaped molecules with three mutually immiscible arms in a radial arrangement, 29 such as mikto-arm star copolymers [34][35][36] and star polyphiles. 37 By microphase separation, the three immiscible components self-assemble into three distinct nanodomains.…”

Section: 3233mentioning

confidence: 99%

Polycontinuous geometries for inverse lipid phases with more than two aqueous network domains

et al. 2013

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Inverse bicontinuous cubic phases with two aqueous network domains separated by a smooth bilayer are firmly established as equilibrium phases in lipid/water systems. The purpose of this article is to highlight the generalisations of these bicontinuous geometries to polycontinuous geometries, which could be realised as lipid mesophases with three or more network-like aqueous domains separated by a branched bilayer. An analysis of structural homogeneity in terms of bilayer width variations reveals that ordered polycontinuous geometries are likely candidates for lipid mesophase structures, with similar chain packing characteristics to the inverse micellar phases (that once were believed not to exist due to high packing frustration). The average molecular shape required by global geometry to form these multi-network phases is quantified by the surfactant shape parameter, v/(al); we find that it adopts values close to those of the known lipid phases. We specifically analyse the 3etc(187 193) structure of hexagonal symmetry P6 3 /mcm with three aqueous domains, the 3dia(24 220) structure of cubic symmetry I 43d composed of three distorted diamond networks, the cubic chiral 4srs(24 208) with cubic symmetry P4 2 32 and the achiral 4srs(5 133) structure of symmetry P4 2 /nbc, each consisting of four intergrown undistorted copies of the srs net (the same net as in the Q G II gyroid phase). Structural homogeneity is analysed by a medial surface approach assuming that the headgroup interfaces are constant mean curvature surfaces. To facilitate future experimental identification, we provide simulated SAXS scattering patterns that, for the 4srs(24 208) and 3dia(24 220) structures, bear remarkable similarity to those of bicontinuous Q G II -gyroid and Q D II -diamond phases, with comparable lattice parameters and only a single peak that cannot be indexed to the wellestablished structures. While polycontinuous lipid phases have, to date, not been reported, the likelihood of their formation is further indicated by the reported observation of a solid tricontinuous mesoporous silicate structure, termed IBN-9, which formed in the presence of surfactants [Han et al

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Section: 3233mentioning

confidence: 99%

Polycontinuous geometries for inverse lipid phases with more than two aqueous network domains

et al. 2013

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“…The form factor is given as F micelle (q) ) N agg 2 core 2 Φ-(q) 2 -F solvent ) ) chain , V chain ) 44750 Å 3 is the volume of the shell-forming block. V core-polymer (F core -F solvent ) ) core , V core-polymer ) 33881 Å 3 is the volume of the core-forming block.…”

Section: Appendixmentioning

confidence: 99%

Association and Structure of Thermosensitive Comblike Block Copolymers in Aqueous Solutions

et al. 2008

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The structures and association properties of thermosensitive block copolymers of poly(methoxyoligo(ethylene glycol) norbornenyl esters) in D 2 O were investigated by small angle neutron scattering (SANS). Each block is a comblike polymer with a polynorbornene (PNB) backbone and oligo ethylene glycol (OEG) side chains (one side chain per NB repeat unit). The chemical formula of the block copolymer is (OEG 3 NB) 79 -(OEG 6.6 NB) 67 , where subscripts represent the degree of polymerization (DP) of OEG and NB in each block. The polymer concentration was fixed at 2.0 wt % and the structural changes were investigated over a temperature range between 25 and 68°C. It was found that at room temperature polymers associate to form micelles with a spherical core formed by the block (OEG 3 NB) 79 and corona formed by the block (OEG 6.6 NB) 67 and that the shape of the polymer in the corona could be described by the form factor of rigid cylinders. At elevated temperatures, the aggregation number increased and the micelles became more compact. At temperatures around the cloud point temperature (CPT) T ) 60°C a correlation peak started to appear and became pronounced at 68°C due to the formation of a partially ordered structure with a correlation length ∼349 Å.

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“…21 The design and synthesis of novel star copolymers with characteristic architectures such as star block copolymers and heteroarm, or miktoarm (mixed) star polymers have attracted significant attention because of their interesting structures and properties. [22][23][24][25][26][27][28] Amphiphilic star block copolymers can form a variety of superstructures via self-organization, and the resulting assembled structures depend on the branched architecture, chemical nature of individual components, composition and molecular weight. Stimuli-responsive star polymers such as temperature-and pH-sensitive stars have also attracted significant interest because of their characteristic stimuli-responsive properties, which originate from their branched architecture.…”

Section: Introductionmentioning

confidence: 99%

Temperature-responsive self-assembly of star block copolymers with poly(ionic liquid) segments

Mori

Ebina

Kambara

et al. 2012

Polym J

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Novel star block copolymers containing poly(N-vinylimidazolium salt) as a poly(ionic liquid) segment and poly(N-isopropylacrylamide) (poly(NIPAAm)) as a thermoresponsive segment were synthesized by reversible additionfragmentation chain transfer (RAFT) polymerization. Two R-designed tetrafunctional chain transfer agents (CTAs), including a xanthate-type CTA and a dithiocarbamate-type CTA, were compared for the polymerization of 1-ethyl-3-vinylimidazolium bromide (VEI-Br), which is an ionic liquid-type monomer. The dithiocarbamate-type tetrafunctional CTA was the most efficient CTA for the controlled synthesis of four-armed poly(VEI-Br) stars with low polydispersity values and controlled molecular weights. Star block copolymers with inner thermoresponsive segments connected to their core were synthesized by the RAFT polymerization of VEI-Br, using poly(NIPAAm) stars. In contrast, the RAFT polymerization of NIPAAm using poly(VEI-Br) stars afforded star block copolymers, with block arms consisting of outer block copolymer segments of thermoresponsive poly(NIPAAm). Thermally induced phase separation behavior and assembled structures of star block copolymers were studied in aqueous solution. Keywords: block copolymer; micelle; poly(ionic liquid); self-assembly; star polymer; star block copolymer; thermoresponsive polymer INTRODUCTION Recently, considerable attention has been paid to polymerized ionic liquids or polymeric ionic liquids, which are macromolecules obtained from the polymerization of ionic liquid monomers. [1][2][3] Polymeric ionic liquids with unique and attractive properties can be obtained by adjusting the structure of the cation (for example, imidazolium, pyridinium and tetraalkylammonium) and the anion (for example, halide, tetrafluoroborate and hexafluorophosphate). Potential applications of polymeric ionic liquids include polymeric electrolytes, catalytic membranes, ionic conductive materials, CO 2 absorbents, microwave absorbents and porous materials. Imidazolium salt is the most popular cation introduced into polymer backbones. A variety of polymers containing imidazolium moieties on their side chains have been developed, including poly(meth)acrylate, 4-7 polystyrene 8,9 and poly(N-vinyl imidazolium) 10-13 derivatives. The majority of these poly(ionic liquid)s were prepared by conventional radical polymerization. In addition to the structure of the substituent on the imidazolium ring, the solubility and properties of poly(Nvinylimidazolium salt) depend on the structure of the counteranion.As a result of recent progress in controlled radical polymerization (also known as controlled or living radical polymerization or reversible deactivation radical polymerization), well-defined block copolymers containing imidazolium moieties have been synthesized. 14,15 For example, Waymouth et al. 16,17 demonstrated the

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Linear and non-linear triblock terpolymers. Synthesis, self-assembly in selective solvents and in bulk

Cited by 425 publications

References 122 publications

Polycontinuous geometries for inverse lipid phases with more than two aqueous network domains

Polycontinuous geometries for inverse lipid phases with more than two aqueous network domains

Association and Structure of Thermosensitive Comblike Block Copolymers in Aqueous Solutions

Temperature-responsive self-assembly of star block copolymers with poly(ionic liquid) segments

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