Fibrillar structure of self‐assemblies formed from heterocomplementary monomers linked through sextuple hydrogen‐bonding arrays

Buhler, Eric; Candau, S. J.; Schmidt, J.; Talmon, Yeshayahu; Kolomiets, Elena; Lehn, Jean‐Maríe

doi:10.1002/polb.20960

Cited by 18 publications

(16 citation statements)

References 44 publications

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“…Figure 5 shows the fits realized for poly(BA‐CH) by means of the form factor80, 81 derived for rigid rod particles given by where L is the contour length of the rod. The high q data can be fitted by a Guinier expression for the form factor of the section:82 where r c is the radius of gyration of the cross‐section. By fitting the two equations above to the experimental data, one can determine the linear mass density (µ, mass per unit length) of the polymers, the cross‐sectional area ( a c ) and r c .…”

Section: Resultsmentioning

confidence: 99%

Cooperative, bottom‐up generation of rigid‐rod nanostructures through dynamic polymer chemistry

Folmer-Andersen¹,

Candau²,

Joulie³

et al. 2010

Polymer International

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International audienceA set of carbazole- and benzene-derived di(aldehyde) and di(acylhydrazine) monomers containing hexaglyme groups to impart water solubility has been synthesized. Mixing a given di(aldehyde) and di(acylhydrazine) pair in acidic aqueous solution causes polymerizationthroughreversibleacylhydrazonecondensation.Thestructuresof theresultantamphiphilicpolyacylhydrazones have been studied using 1H NMR spectroscopy, matrix-assisted laser desorption ionization mass spectrometry, small-angle neutron scattering, transmission electron microscopy, size exclusion chromatography/multi-angle laser light scattering (SECMALLS) andUV-visibleandfluorescence spectrophotometries. All theavailabledatasupport theexistenceof structurallyrelated rod-like nanostructures of variable lengths and constant diameters of approximately 5 nm in all cases,which are interpreted as corresponding to individually folded polymer chains. On the basis of these studies, molecular models are proposed in which the hydrophobic, aromatic polymer backbones assume helical conformations allowing for hydrophobically driven π-stacking, while exposing the hydrophilic hexaglyme groups to the solvent. The molecular models are in agreement with the observed physical dimensions of the nanostructures, and are further supported by the observation of strong hypochromic effects on changing the solvent from dimethylformamide to water. Additionally, the reversible polymerization process is found to be cooperative. 1H NMR and SEC-MALLS studies reveal severe deviations from statistically predicted product distributions under imbalanced stoichiometry, which are characteristic of nucleation–elongation behaviour

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Section: Resultsmentioning

confidence: 99%

Cooperative, bottom‐up generation of rigid‐rod nanostructures through dynamic polymer chemistry

Folmer-Andersen¹,

Candau²,

Joulie³

et al. 2010

Polymer International

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“…Small-angle neutron scattering (SANS) was used to verify that the aggregates formed in the solvent did not change as the solvent changed. 22 In another case, for the much studied microemulsion of octane, water, and nonionic surfactant C 12 E 5 (pentaethylene glycol monododecyl ether), normal octane was replaced by isooctane. 19 We redid the phase diagram to establish the slightly altered phase boundaries and successfully imaged the system at different compositions and temperatures by a combination of cryo-TEM and cryo-SEM (see below).…”

Section: Specimen Preparationmentioning

confidence: 99%

Extending Cryo-EM to Nonaqueous Liquid Systems

Ya’akobi

Talmon

2021

Acc. Chem. Res.

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Conspectus Cryogenic-temperature transmission electron microscopy (cryo-TEM) of aqueous systems has become a widely used methodology, especially in the study of biological systems and synthetic aqueous systems, such as amphiphile and polymer solutions. Cryogenic-temperature scanning electron microscopy (cryo-SEM), while not as widely used as cryo-TEM, is also found in many laboratories of basic and applied research. The application of these methodologies, referred to collectively as cryogenic-temperature electron microscopy (cryo-EM) for direct nanostructural studies of nonaqueous liquid systems is much more limited, although such systems are important in basic research and are found in a very large spectrum of commercial applications. The study of nonaqueous liquid systems by cryo-EM poses many technical challenges. Specimen preparation under controlled conditions of air saturation around the specimen cannot be performed by the currently available commercial system, and the most effective cryogen, freezing ethane, cannot be used for most such liquid systems. Imaging is often complicated by low micrograph contrast and high sensitivity of the specimens to the electron beam. At the beginning of this Account, we describe the basic principles of cryo-EM, emphasizing factors that are essential for successful direct imaging by cryo-TEM and cryo-SEM. We discuss the peculiarities of nonaqueous liquid nanostructured systems when studied with these methodologies and how the technical difficulties in imaging nonaqueous systems, from oil-based to strong acid-based liquids, have been overcome, and the applicability of cryo-TEM and cryo-SEM has been expanded in recent years. Modern cryo-EM has been advanced by a number of instrumental developments, which we describe. In the TEM, these include improved electron field emission guns (FEGs) and microscope optics, the Volta phase plate to enhance image contrast by converting phase differences to amplitude differences without the loss of resolution by an objective lens strong underfocus, and highly sensitive image cameras that allow the recording of TEM images with minimal electron exposure. In the SEM, we take advantage of improved FEGs that allow imaging at a low (around 1 kV) electron acceleration voltage that is essential for high-resolution imaging and for avoiding specimen charging of uncoated nonconductive specimens, better optics, and a variety of sensitive detectors that have considerably improved resolution and, under the proper conditions, give excellent contrast even between elements quite close on the periodic table of the elements, such as the most important oxygen and carbon atoms. Finally we present and analyze several examples from our recent studies, which illustrate the issues presented above, including the remarkable progress made in recent years in this field and the strength and applicability of cryo-EM methodologies.

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“…SANS experiments 31 were performed on the D11 beamline at Institut Laue-Langevin at Grenoble (ILL, France) [31][32][33][34] and on the PACE beamline at the Léon Brillouin Laboratory at Saclay (LLB, France). At ILL, an incident wavelength  of 6 Å was used for 3 sample-to-detector distances (1.2, 8 and 40 m), allowing to access a total range for the magnitude of the scattering vector q varying between 0.003 Å -1 and 0.3 Å -1 .…”

Section: Small Angle Neutron Scattering (Sans)mentioning

confidence: 99%

“…At ILL, an incident wavelength  of 6 Å was used for 3 sample-to-detector distances (1.2, 8 and 40 m), allowing to access a total range for the magnitude of the scattering vector q varying between 0.003 Å -1 and 0.3 Å -1 . [31][32][33][34] At LLB, two different wavelengths  (13 and 4.6 Å) and 3 sample-detector distances were used: 1, 3 and 4.7 m. A total scattering vector range of 0.004 ≤ q (Å -1 ) ≤ 0.3 was thus investigated.…”

Section: Small Angle Neutron Scattering (Sans)mentioning

confidence: 99%

Structural properties of contractile gels based on light-driven molecular motors: a small-angle neutron and X-ray study

et al. 2020

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Fibrillar structure of self‐assemblies formed from heterocomplementary monomers linked through sextuple hydrogen‐bonding arrays

Cited by 18 publications

References 44 publications

Cooperative, bottom‐up generation of rigid‐rod nanostructures through dynamic polymer chemistry

Cooperative, bottom‐up generation of rigid‐rod nanostructures through dynamic polymer chemistry

Extending Cryo-EM to Nonaqueous Liquid Systems

Structural properties of contractile gels based on light-driven molecular motors: a small-angle neutron and X-ray study

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