From Smart Denpols to Remote‐Controllable Actuators: Hierarchical Superstructures of Azobenzene‐Based Polynorbornenes

Lee

et al. 2017

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Since the molecular self‐assembly of nanomaterials is sensitive to their surface properties, the molecular packing structure on the surface is essential to build the desired chemical and physical properties of nanomaterials. Here, a new nanosurfactant is proposed for the automatic construction of macroscopic surface alignment layer for liquid crystal (LC) molecules. An asymmetric nanosurfactant (C60NS) consisted of mesogenic cyanobiphenyl moieties with flexible alkyl chains and a [60]fullerene nanoatom is newly designed and precisely synthesized. The C60NS directly introduced in the anisotropic LC medium is self‐assembled into the monolayered protrusions on the surface because of its amphiphilic nature originated by asymmetrically programmed structural motif of LC‐favoring moieties and LC‐repelling groups. The monolayered protrusions constructed by the phase‐separation and self‐assembly of asymmetric C60NS nanosurfactant in the anisotropic LC media amplify and transfer the molecular orientational order from surface to bulk, and finally create the automatic vertical molecular alignment on the macroscopic length scale. The asymmetric C60NS nanosurfactant and its self‐assembly described herein can offer the direct guideline of interface engineering for the automatic molecular alignments.

Section: Introductionmentioning

confidence: 99%

Asymmetric Fullerene Nanosurfactant: Interface Engineering for Automatic Molecular Alignments

Lee

et al. 2017

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Polymers for Advanced Techs

“…Because the azobenzene‐based trans‐isomer can be converted to the cis‐one upon UV light irradiation and return to the trans‐isomer by visible light irradiation or in dark storage, azobenzene units are often used as the light‐responsive group. Such a strategy is widely employed to make polymer photo‐switchable . We also have adopted this method to prepare starch‐based pH‐responsive and light‐responsive hydrogel.…”

Section: Resultsmentioning

confidence: 99%

“…Such a strategy is widely employed to make polymer photo-switchable. 17,18 We also have adopted this method to prepare starch-based pH-responsive and light-responsive hydrogel. Herein, another component to act photofunction is introduced.…”

Section: Characteristics Of Starch-based Dual Photo-functional Hydrmentioning

confidence: 99%

Formation and characteristics of starch‐based dual photo‐function composite hydrogel

Xiao

2019

Starch‐based dual photo‐functional hydrogel (SDPH) was obtained via incorporating the azo group onto the backbone of polymeric network and titanium dioxide within the gel at the same time. The structure and composition of SDPH were confirmed with Fourier transform infrared spectrometer, ultraviolet‐visible (UV‐Vis) spectroscopy, thermogravimetric analysis, and energy scattering X‐ray spectroscopy. Scanning electron microscopy observation revealed that titanium dioxide was well dispersed within SDPH. It was found that SDPH not only showed a reversible light‐sensitive behavior but also possessed photo‐catalytic activity. Moreover, the dual photo‐characteristics could be modulated by simply varying the initial amount of titanium dioxide.

Advanced Optical Materials

“…By illuminating this array with a complex light pattern, they were able to simulate the asymmetric movement of cilia in the lungs ( Figure a). Azobenzenes have also been incorporated into dendronized polymers, synthesized by ring‐opening metathesis (Figure b) . This bottom‐up approach to the design of hierarchical superstructures allows for a fine control of the structure–property relationships of the final material.…”

Section: Polymeric Photoactuators: Moving Toward Artificial Musclesmentioning

confidence: 99%

Section: Polymeric Photoactuators: Moving Toward Artificial Musclesmentioning

confidence: 99%

Photoreversible Soft Azo Dye Materials: Toward Optical Control of Bio‐Interfaces

Chang

Fedele

Priimägi

et al. 2019

systems interact with artificial materials, researchers have now assembled a versatile toolkit of materials and processes that allows one to fine-tune interactions at the interface, tailoring specific biological responses on demand. These strategies for biocontrol can be broadly categorized as chemical (charge, ligand presence, surface groups), material changes (moisture content, stiffness), or morphological changes (molecular orientation, surface topography, or mechanical actuation). Rational design of materials for biological interface applications has a unique set of challenges due to the unique requirements of a wide range of biological systems, since different tissues present specific compositions, with their own elasticity, structural organization, and triggering mechanisms. Even within a single organ or tissue, mechanical properties can vary widely depending on the region. A recent study of viscoelasticity in live mouse brain tissue for example found a tenfold difference within the brain depending on the region and morphological structure studied. [2] However, most biological tissues are far less stiff, and far more viscoelastic than typical artificial materials employed at their interface, especially early artificial cell culture materials, which can be much stiffer than in vivo extracellular matrix by many orders of magnitude. [3] In vivo, cells interface with a surrounding microenvironment consisting of an intricate macromolecular network of proteins and sugars swollen in an aqueous media gel. Therefore, the interaction between cells and the extracellular matrix (ECM) in the body is complex and involves a variety of cues related to topography, chemical markers, protein composition, solubility factors, and mechanical properties such as stiffness and elasticity (Figure 1a). [4] Yet much research over the past decades was focused on studying in vitro the effects of each of these signals on cell behavior, with a particular interest on the chemical factors, whereas only recently more advanced biomaterials with controlled physicomechanical properties have been developed, such as those with tunable and variable stiffness, alignment and orientation of key functional groups, and mechanical actuation. There is a large range of stiffness in human tissue, where bone (≈100 GPa) is nine orders of magnitude harder than brain tissue (≈0.1 kPa). [4] Therefore, biomaterial researchers assume a complex task of providing materials and processing technologies for controlling stiffness and micro-and nanostructures in Photoreversible optically switchable azo dye molecules in polymer-based materials can be harnessed to control a wide range of physical, chemical, and mechanical material properties in response to light, that can be exploited for optical control over the bio-interface. As a stimulus for reversibly influencing adjacent biological cells or tissue, light is an ideal triggering mechanism, since it can be highly localized (in time and space) for precise and dynamic control over a biosystem, and low-power visible light...