Defect-mediated curvature and twisting in polymer crystals

Kübel, Christian; Gonzalez-Ronda, Lebzylisbeth; Drummy, Lawrence F.; Martin, David C.

doi:10.1002/1099-1395(200012)13:12<816::aid-poc322>3.0.co;2-i

Cited by 34 publications

(22 citation statements)

References 88 publications

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“…As seen from the encircled areas, all of the disclinations are of half‐integer type and those of opposite sign are always found near one another, i.e., there are not clusters of positive or negative without their opposite, indicative of a liquid crystalline texture 14. These disclinations of course represent regions of high curvature, which have also been observed in other rigid polymers 15. We note that a smectic mesophase was identified for pBTTT in our previous work 8e.…”

Section: Resultssupporting

confidence: 76%

In‐Plane Liquid Crystalline Texture of High‐Performance Thienothiophene Copolymer Thin Films

Zhang

Hudson

DeLongchamp

et al. 2010

Adv Funct Materials

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Poly(2,5‐Bis(3‐alkylthiophen‐2‐yl)thieno[3,2‐b]thiophenes (pBTTTs) are a new class of solution‐processable polymer semiconductors with high charge carrier mobilities that rival amorphous silicon. This exceptional performance is thought to originate in the microstructure of pBTTT films, which exhibit high crystallinity and a surface topography of wide terraces. However, the true lateral grain size has not been determined, despite the critical impact grain boundaries can have on the charge transport of polymer semiconductors. Here a strategy for determining the lateral grain structure of pBTTT using dark‐field transmission electron microscopy (DF‐TEM) and subsequent image analysis is presented. For the first time, it is revealed that the in‐plain pBTTT crystal orientation varies smoothly across a length scale significantly less than one micrometer (e.g., with only small angles between adjacent diffracting regions). The pBTTT polymers thus exhibit an in‐plane liquid crystalline texture. This microstructure is different from what has been reported for small molecule semiconductors or polymer semiconductors such as poly(3‐hexyl thiophene) (P3HT). Even though films processed differently exhibit different apparent domain sizes, they exhibit similar charge carrier hopping activation energies because they possess similar low densities of abrupt grain boundaries.

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Section: Resultssupporting

confidence: 76%

In‐Plane Liquid Crystalline Texture of High‐Performance Thienothiophene Copolymer Thin Films

Zhang

Hudson

DeLongchamp

et al. 2010

Adv Funct Materials

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“…In 2010, Nam et al . 28 reported tumor targeting nanoparticles for optical/MRI dual imaging based on self-assembled Glycol Chitosan (GC) which is chemically modified with 5β-Cholanic Acid (CA). For optical imaging, (GC-CA) is used as a chelate for Gd(III) and Cy5.5 is conjugated.…”

mentioning

confidence: 99%

Hybrid Core-Shell (HyCoS) Nanoparticles produced by Complex Coacervation for Multimodal Applications

Vecchione

Grimaldi

Forte

et al. 2017

Sci Rep

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Multimodal imaging probes can provide diagnostic information combining different imaging modalities. Nanoparticles (NPs) can contain two or more imaging tracers that allow several diagnostic techniques to be used simultaneously. In this work, a complex coacervation process to produce core-shell completely biocompatible polymeric nanoparticles (HyCoS) for multimodal imaging applications is described. Innovations on the traditional coacervation process are found in the control of the reaction temperature, allowing a speeding up of the reaction itself, and the production of a double-crosslinked system to improve the stability of the nanostructures in the presence of a clinically relevant contrast agent for MRI (Gd-DTPA). Through the control of the crosslinking behavior, an increase up to 6 times of the relaxometric properties of the Gd-DTPA is achieved. Furthermore, HyCoS can be loaded with a high amount of dye such as ATTO 633 or conjugated with a model dye such as FITC for in vivo optical imaging. The results show stable core-shell polymeric nanoparticles that can be used both for MRI and for optical applications allowing detection free from harmful radiation. Additionally, preliminary results about the possibility to trigger the release of a drug through a pH effect are reported.

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“…The formation of these ribbons (as distinct from cylindrical fibres) allows the ready observation of a pronounced overall "twist". Twisted fibres have often been associated with the presence of chirality in the polymeric material, 42 although chirality is not a prerequisite for twisting, and helices of opposite chirality may be produced from the same material. 43 There may be other mechanism for the formation of helices such as buckling at the collector; in the case of cellulose the behaviour has been attributed to the nonuniform deformation of filaments in the presence of a liquid crystalline phase.…”

Section: Wpc-peomentioning

confidence: 99%

Electrospinning of food-grade nanofibres from whey protein

Zhong

Mohan

Bell

et al. 2018

International Journal of Biological Macromolecules

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In this study, electrospinning has been employed to produce micro to nano scale fibres of whey protein in order to investigate their potential for use in the food industry. Initially, spinning of pure whey protein proved challenging; so in order to facilitate the spinning of freshly prepared aqueous solutions, small amounts of polyethylene oxide (as low as 1% w/w in solution) were incorporated in the spinning solutions. The electrospun composite polyethylene-oxide/whey fibres exhibited diameters in the region of 100 to 400 nm, showing the potential to build fibre bundles from this size up. Time-dependent examinations of pure whey protein aqueous solutions were conducted using rheometery and small angle neutron scattering techniques, with the results showing a substantial change in the solution properties with time and stirring; and allowing the production of fibres, albeit with large diameters, without the need for an additive. The spinability is related to the potential of the whey protein composites to form aggregate structures, either through hydration and interaction with neighbouring proteins, or through interaction with the polyethylene oxide.

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Defect-mediated curvature and twisting in polymer crystals

Cited by 34 publications

References 88 publications

In‐Plane Liquid Crystalline Texture of High‐Performance Thienothiophene Copolymer Thin Films

In‐Plane Liquid Crystalline Texture of High‐Performance Thienothiophene Copolymer Thin Films

Hybrid Core-Shell (HyCoS) Nanoparticles produced by Complex Coacervation for Multimodal Applications

Electrospinning of food-grade nanofibres from whey protein

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