Hierarchical Assembly of a Dual-responsive Macroscopic Insulated Molecular Wire Bundle in a Gradient System

Abstract

Here, we report the hierarchical self-assembly of a cationic gemini amphiphile, Azo 1, in a composition gradient solution generated using solvent evaporation. As the gradient solution is formed, Azo 1 forms nanorods in the lower region of the solution. Depending on solvent composition, these nanorods can further develop into nanofibres, which can then intertwine to form double helices and other types of nanohelices in the upper region of the solution. Finally, a macroscopic wire bundle is formed via the fusion of nanohelices; this ribbon-like bundle exhibits elasticity and linear ohmic resistance properties. More intriguingly, this bundle exhibits photoresponsive properties that affect its deformation and conductivity, as well as a rapid electroresponse that affects its conductivity, indicating that it is feasible to control the charge pathway.

Light-induced dynamic shaping and self-division of multipodal polyelectrolyte-surfactant microarchitectures via azobenzene photomechanics

“…The Q a and Q b peaks were assigned to the azoTAB molecular length (~1.7 nm)33 and intermolecular distance between adjacent surfactants (~0.4 nm), respectively. The shoulder peak at Q ~ 2 Å −1 (d ~ 0.3 nm) was in agreement with reported π-π stacking distances for trans- azobenzene groups38, suggesting that charge screening of the trimethylammonium headgroups by carboxylate groups of PAA facilitated hydrophobic packing of the azoTAB molecules into the hexagonal mesostructure.…”

Synthesis and properties of flexible nanocable with carbon nanotube @ polymer hierarchical structure

“…Apart from indicating typical insulating behavior of the polymer sheath, there are several other notable features in this curve. First, the nearly horizontal segment from 0 to 12 V is an intrinsic transport characteristic of the PGMA sheath which is connected to its polarization behavior (e.g., ionic and dipolar reorientation conduction) [32], and gives rise to a leakage current of less than 12 nA at 12 V. Interestingly, the total resistance of the device is approximated to 1 GΩ; a value which is much higher than that of semiconducting polymer nanowires [33]. In this note that electric conduction can also be facilitated, at higher voltages, by the tunneling effect between SWNTs, if the surrounding insulating layer is not sufficiently thick [34][35][36].…”

Self‐Assembly of Photoresponsive Molecular Amphiphiles in Aqueous Media

“…Taking inspiration from molecular motions in muscle tissues, a photoresponsive hierarchical self‐assembled structure of a cationic gemini azobenzene amphiphile 24 was developed by Liu and co‐workers (Figure 27). [230] The azobenzene amphiphile 24 assembled hierarchically from nanorods into crystalline helical twisted bundles (observed by polarized optical microscopy, POM) by organic solvent evaporation during 2 days. The resulting bundled helices (≈3 mm in length and ≈25 μm in diameter) bent towards the incident light source (302 nm light, 120 min) from an initial angle of 36° to a saturated flexion angle of 50° with an actuation speed of 1.9×10 −3 degree s −1 , providing a millimeter length‐scale anisotropic actuation based on modulation of the supramolecular polymer interactions via photoswitching of the azobenzene amphiphile 24 .…”

“…Adapted with permission from ref. [230]. Copyright 2015, Macmillan Publishers Limited, part of Springer Nature.…”