Directing self-assembly in macromolecular systems: Hydrogen bonding in ordered polymers

2004 ◽  
Vol 76 (7-8) ◽  
pp. 1337-1343 ◽  
Author(s):  
C.-Y. Chao ◽  
X. Li ◽  
C. K. Ober

Hydrogen-bonded side-chain liquid-crystalline block copolymers (SCLCBCPs) containing block segments with proton donors were combined with functionalized mesogenic pendent groups. Studies of a wide range of mesogen and polymer combinations were carried out to study the relationship between morphology and mesophase behavior. The thermal behaviors of the resulting self-assembled microstructures were also examined. A model of the assembly process leading to mesogenic group organization corresponding to different compositions was proposed.

2021 ◽  
Vol 22 (17) ◽  
pp. 9634
Author(s):  
Moran Aviv ◽  
Dana Cohen-Gerassi ◽  
Asuka A. Orr ◽  
Rajkumar Misra ◽  
Zohar A. Arnon ◽  
...  

Supramolecular hydrogels formed by the self-assembly of amino-acid based gelators are receiving increasing attention from the fields of biomedicine and material science. Self-assembled systems exhibit well-ordered functional architectures and unique physicochemical properties. However, the control over the kinetics and mechanical properties of the end-products remains puzzling. A minimal alteration of the chemical environment could cause a significant impact. In this context, we report the effects of modifying the position of a single atom on the properties and kinetics of the self-assembly process. A combination of experimental and computational methods, used to investigate double-fluorinated Fmoc-Phe derivatives, Fmoc-3,4F-Phe and Fmoc-3,5F-Phe, reveals the unique effects of modifying the position of a single fluorine on the self-assembly process, and the physical properties of the product. The presence of significant physical and morphological differences between the two derivatives was verified by molecular-dynamics simulations. Analysis of the spontaneous phase-transition of both building blocks, as well as crystal X-ray diffraction to determine the molecular structure of Fmoc-3,4F-Phe, are in good agreement with known changes in the Phe fluorination pattern and highlight the effect of a single atom position on the self-assembly process. These findings prove that fluorination is an effective strategy to influence supramolecular organization on the nanoscale. Moreover, we believe that a deep understanding of the self-assembly process may provide fundamental insights that will facilitate the development of optimal amino-acid-based low-molecular-weight hydrogelators for a wide range of applications.


2011 ◽  
Vol 123 (3) ◽  
pp. 255-263 ◽  
Author(s):  
KUMARASAMY GAYATHRI ◽  
SUBRAMANIAN BALAMURUGAN ◽  
PALANINATHAN KANNAN

Author(s):  
G. Kossmehl ◽  
M. Schulz ◽  
H.-M. Vieth ◽  
A. Van Der Est

1996 ◽  
Vol 05 (04) ◽  
pp. 735-755 ◽  
Author(s):  
D. GONIN ◽  
B. GUICHARD ◽  
M.C.J. LARGE ◽  
T. DANTAS DE MORAIS ◽  
C. NOËL ◽  
...  

In this paper we consider the behavior of a number of side chain liquid crystal polymers having the same mesogenic group and relate their liquid crystalline behavior to their polarization and nonlinear optical properties. We show that the liquid crystallinity of the materials results in an enhancement of the polar order over that of isotropic materials, in qualitative agreement with molecular statistical models.


Soft Matter ◽  
2020 ◽  
Vol 16 (23) ◽  
pp. 5497-5505 ◽  
Author(s):  
P. Xu ◽  
T. Erdem ◽  
E. Eiser

Inspired by the relationship between the ordered architecture of aragonite crystals and biopolymers found in natural nacre, we present a facile strategy to construct organic/inorganic nanocomposites with hierarchical structure via a water-evaporation driven self-assembly process.


1996 ◽  
Vol 425 ◽  
Author(s):  
Y. Watanabe ◽  
N. Koide

AbstractNovel side chain type liquid crystalline polymers, polythiophene and poly(aryleneethynylene) [PAE], containing a mesogenic group in the side chain were synthesized. Polythiophene derivatives were obtained by dehalogenative polycondensation with zero-valence nickel complex under mild condition. PAE type polymers were obtained by coupling dihalo aromatic compound with diethynyl aromatic compound. Their thermal properties were examined by differential scanning calorimetry, optical microscopy and X-ray diffractometry. All polymers exhibited a smectic or nematic mesophase depending upon the polymer backbone and pendant mesogenic group. Polythiophene derivatives exhibited electrochemical activity. Annealing polythiophene derivatives led to a lower oxidation potential and a higher conductivity. The degree of the orientation of the polymer backbone was supported by polarized UV-vis measurement. An effective conjugated length became longer by introducing thiophene rings into the polymer backbone. A high quantum yield of fluorescence was observed for PAE type polymers.


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