AFM Visualization of Individual and Periodic Assemblies of a Helical Dendronized Polyphenylacetylene on Graphite

Percéc, Virgil; Rudick, Jonathan G.; Wagner, Martin; Obata, Makoto; Mitchell, Catherine M.; Cho, Wook‐Dong; Magonov, Sergei

doi:10.1021/ma060845g

Cited by 55 publications

(70 citation statements)

References 47 publications

(62 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…71 The detailed AFM study 73 of another of those dendronized PPAs (i.e., poly-21) deposited on HOPG ( Figure 15) showed individual macromolecules as oblate cylindrical objects. Their orientation in the first layer, the one directly adsorbed on the HOPG, reflected the underlying lattice symmetry due to the adsorption of the long alkyl tails.…”

Section: Spin Coating and Thermal Annealingmentioning

confidence: 99%

Chiral nanostructure in polymers under different deposition conditions observed using atomic force microscopy of monolayers: poly(phenylacetylene)s as a case study

2017

View full text Add to dashboard Cite

This is the peer reviewed version of the following article: Freire, F. Quiñoá, E.; Riguera, R.; "Chiral nanostructure in polymers under different deposition conditions observed using atomic force microscopy of monolayers: poly(phenylacetylene)s as a case study" Chemical Communications, 2017, 53, 481-492 PPAs by atomic-force microscopy (AFM) are presented, with special attention to the methods for the preparation of monolayers, and their consequences in the quality of the AFM images. Thus, monolayers formed by drop casting, spin coating followed by crystallization or annealing, Langmuir-Blodgett and Langmuir-Schaefer methods, onto highly oriented pyrolytic graphite (HOPG) or mica are described, together with the AFM images and the resulting helical structure obtained for different PPAs. Also, some conclusions are assessed both on the adequacy of the different techniques for the formation of monolayers and on the solid supports employed to elucidate the secondary structure of different PPAs.

show abstract

Section: Spin Coating and Thermal Annealingmentioning

confidence: 99%

Chiral nanostructure in polymers under different deposition conditions observed using atomic force microscopy of monolayers: poly(phenylacetylene)s as a case study

2017

View full text Add to dashboard Cite

show abstract

“…Similar results were obtained for self-organized dendronized poly(phenylacetylenes) where column diameters determined in the bulk by XRD were slightly smaller than the column widths measured by AFM on HOPG substrate. [31] Rationale for such differences in the column widths observed by AFM on HOPG and XRD in bulk was provided in terms of epitaxy of the peripheral alkyl tails on surface, leading to formation of more flattened oblate structures on HOPG. [31] Likewise, in our own work on liquidcrystalline perylene bisimides bearing trialkylphenyl side chains, we have observed this phenomenon.…”

mentioning

confidence: 99%

Columnar Mesophases Based on Zinc Chlorophyll Derivatives Functionalized with Peripheral Dendron Wedges

Sengupta

Uemura

Patwardhan

et al. 2011

Chemistry A European J

View full text Add to dashboard Cite

A chlorophyll derivative with a central zinc ion, a methoxy functionality at its 3(1)-position, and functionalized with a second-generation dendron (3,4-3,4,5)12G2-CH(2)OH at its 17(2)-position was synthesized starting from natural chlorophyll a (Chl a). This compound exhibits liquid crystalline (LC) behavior and its mesomorphic properties have been characterized by differential scanning calorimetry (DSC), polarisation optical microscopy (POM), powder X-ray diffraction (XRD), and scanning probe microscopy (SPM). A combination of powder XRD, high resolution scanning tunneling microscopy (STM), and atomic force microscopy (AFM) experiments revealed the formation of nano-segregated well-ordered columnar tubular superstructures consisting of about five molecules in the column stratum. These self-assembled columns are further self-organized into a two-dimensional oblique unit cell lattice. Semiconducting behavior of this compound has been studied by pulse-radiolysis time-resolved microwave conductivity (PR-TRMC) method and charge carrier mobility values of ∼10(-2) cm(2) V(-1) s(-1) are observed. Such organized columnar superstructures constructed from semisynthetic zinc chlorins are reminiscent of the tubular organization of the bacteriochlorophyll dyes in the light-harvesting chlorosomal antennae of green sulphur bacteria.

show abstract

“…[40][41][42][43][44][45][46] Part of their important findings has been surveyed in the review by Percec and Rudick in this special series. [27] Owing to the superior selfassembling ability of Percec-type dendrons, the resultant MSPAs exhibit fascinating phase behaviors.…”

Section: Rod-like Mspas and Their Columnar Lc Phasesmentioning

confidence: 99%

“…Such rod-like molecules can be clearly visualized under atomic force microscope (AFM). [40,44,46] On the basis of XRD, particularly two-dimensional (2-D) XRD of the oriented fibers, the monodendronized PAs are found to be able to form the F phases with intracolumnar order or even F crystal phases, wherein the columns are helical porous. Increasing temperature can result in a transition towards the ordinary F phase, accompanying by a decrease of the external column diameter and the disappearance of the helical pore.…”

Section: Rod-like Mspas and Their Columnar Lc Phasesmentioning

confidence: 99%

Molecular Shapes of Monosubstituted Polyacetylenes in their Liquid Crystalline Phases

Liu¹,

Yu²,

Chen³

2009

Macro Chemistry & Physics

View full text Add to dashboard Cite

In this short review, we discuss the molecular shapes of monosubstituted polyacetylenes (MSPAs) in their liquid crystalline (LC) phases. Their rigid backbone with high stereoregularity can endow MSPAs with significant shape persistency, which largely determines their LC structures. Helical cis‐cisoidal and cis‐transoidal MSPAs render rod‐like shapes and can form columnar LC (Φ) phases. In the smectic LC (Sm) phases of MSPAs with mesogenic side‐chains, the main chain, with trans‐cisoidal, trans‐transoidal or extended cis‐transoidal conformation, is in fact largely coplanar with the side‐chains, resulting in a sheet‐like molecular shape. From a simple geometric point of view, the rod‐ or sheet‐like MSPA molecules serve as the building block of their LC phases.magnified image

show abstract

AFM Visualization of Individual and Periodic Assemblies of a Helical Dendronized Polyphenylacetylene on Graphite

Cited by 55 publications

References 47 publications

Chiral nanostructure in polymers under different deposition conditions observed using atomic force microscopy of monolayers: poly(phenylacetylene)s as a case study

Chiral nanostructure in polymers under different deposition conditions observed using atomic force microscopy of monolayers: poly(phenylacetylene)s as a case study

Columnar Mesophases Based on Zinc Chlorophyll Derivatives Functionalized with Peripheral Dendron Wedges

Molecular Shapes of Monosubstituted Polyacetylenes in their Liquid Crystalline Phases

Contact Info

Product

Resources

About