Photoresponsive Polymers

Xiong, Xinhong; Campo, Aránzazu del; Cui, Jiaxi

doi:10.1016/b978-0-08-102416-4.00004-1

Cited by 16 publications

(10 citation statements)

References 339 publications

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“…Smart materials that can convert various forms of stimuli (e.g., heat, light, electric field, magnetic field, pH, moisture) to mechanical motions are currently attracting intense attention. − Among all stimuli, light possesses intrinsic advantages such as wireless control, abundant light sources with variable wavelengths, cost-effectiveness, cleanliness, and safety . Photomechanical smart materials have demonstrated great potential for applications as diverse as information storage, sensors, actuators, artificial muscles, self-healing materials, and so forth. − Until now, photomechanical smart materials have been mostly concentrated on carbon-based materials and polymeric materials including organic polymers, liquid-crystalline elastomers, hydrogels, and biopolymers . However, these materials usually possess no or low crystallinity that unavoidably lead to low intrinsic energy conversion efficiencies, impeding their application scopes.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Photoresponsive Crystalline Artificial Muscles Based on PEGylated Covalent Organic Framework Membranes

et al. 2020

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Seeking new photoresponsive materials with high energy conversion efficiency, good mechanical properties, as well as well-defined photoactuation mechanisms is of paramount significance. To address these challenges, we first introduced crystalline covalent organic frameworks (COFs) into the photoactuator field and created a facile fabrication strategy to directly install photoresponsive functional groups (i.e., acylhydrazone) on the skeletons of COFs. Herein, an approach to use polyethylene glycol (PEG) cross-linked dimers as the building blocks of the COF-42 platform was developed and afforded a series of uniform and freestanding membranes (PEG-COF-42) with outstanding mechanical properties (e.g., high flexibility and mechanical strength). Notably, these membranes possessed a fast mechanical response (e.g., bending) to UV light and good reversibility upon blue light or heating. After an in-depth investigation of the photoactuation mechanism via various techniques, we proposed a mechanism for the photoresponsive performance of PEG-COF-42: configurational change of acylhydrazone (i.e., E ↔ Z isomerization) accompanied by an excited-state intramolecular proton transfer (ESIPT) process intramolecularly transferring hydrogens from hydrogen donors (NH) to hydrogen acceptors (oxygen in PEG). Moreover, attributed to the PEG moieties, PEG-COF-42 also demonstrated a vapor-responsive performance. This study not only broadens the application scopes of COFs but also provides new opportunities for the construction of multi-stimuli-responsive materials.

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Section: Introductionmentioning

confidence: 99%

Fabrication of Photoresponsive Crystalline Artificial Muscles Based on PEGylated Covalent Organic Framework Membranes

et al. 2020

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“…A vastly used strategy is represented by carrier systems encapsulating drugs in amphiphilic polymeric systems, which can be equipped with stimulus-sensitive moieties to provide controlled drug release. Drug delivery systems sensitive to stimuli such as light, pH, − ultrasound, , temperature, , enzymes, , and redox potentials − are reported. Adaptation of such stimuli to specific chemical features of diseased skin may enable targeted delivery of sufficient amounts of drugs to specific compartments, e.g., inflammatory infiltrates.…”

Section: Introductionmentioning

confidence: 99%

Oxidation-Sensitive Core–Multishell Nanocarriers for the Controlled Delivery of Hydrophobic Drugs

Rajes

Walker

Hadam

et al. 2021

ACS Biomater. Sci. Eng.

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A synthetic route for oxidation-sensitive core− multishell (osCMS) nanocarriers was established, and their drug loading and release properties were analyzed based on their structural variations. The nanocarriers showed a drug loading of 0.3−3 wt % for the anti-inflammatory drugs rapamycin and dexamethasone and the photosensitizer meso-tetra-hydroxyphenylporphyrin (mTHPP). Oxidative processes of the nanocarriers were probed in vitro by hydrogen peroxide, and the degradation products were identified by infrared spectroscopy supported by ab initio calculations, yielding mechanistic details on the chemical changes occurring in redox-sensitive nanocarriers. Oxidationtriggered drug release of the model drug Nile Red measured and assessed by time-dependent fluorescence spectroscopy showed a release of up to 80% within 24 h. The drug delivery capacity of the new osCMS nanocarriers was tested in ex vivo human skin with and without pretreatments to induce local oxidative stress. It was found that the delivery of mTHPP was selectively enhanced in skin under oxidative stress. The number and position of the thioether groups influenced the physicochemical as well as drug delivery properties of the carriers.

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“…Photo-responsive polymers are special polymers that respond to light and dark conditions and thus give rise to reversible variations in their structure and conformation [ 147 ]. Photo-responsive polymers are obtained by a photo-responsive functional group (chromophore) incorporated into the polymer chain, and based on the chromophore used, the response can be reversible or irreversible [ 148 ]. Polymers containing azobenzenes and spiropyran as the chromophore are the most widely studied photo-responsive polymers [ 149 ].…”

Section: Smart Hydrogelsmentioning

confidence: 99%

Hydrogels Classification According to the Physical or Chemical Interactions and as Stimuli-Sensitive Materials

Bustamante-Torres

Romero-Fierro

Arcentales-Vera

et al. 2021

Gels

149

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Hydrogels are attractive biomaterials with favorable characteristics due to their water uptake capacity. However, hydrogel properties are determined by the cross-linking degree and nature, the tacticity, and the crystallinity of the polymer. These biomaterials can be sorted out according to the internal structure and by their response to external factors. In this case, the internal interaction can be reversible when the internal chains are led by physicochemical interactions. These physical hydrogels can be synthesized through several techniques such as crystallization, amphiphilic copolymers, charge interactions, hydrogen bonds, stereo-complexing, and protein interactions. In contrast, the internal interaction can be irreversible through covalent cross-linking. Synthesized hydrogels by chemical interactions present a high cross-linking density and are employed using graft copolymerization, reactive functional groups, and enzymatic methods. Moreover, specific smart hydrogels have also been denoted by their external response, pH, temperature, electric, light, and enzyme. This review deeply details the type of hydrogel, either the internal structure or the external response. Furthermore, we detail some of the main applications of these hydrogels in the biomedicine field, such as drug delivery systems, scaffolds for tissue engineering, actuators, biosensors, and many other applications.

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Photoresponsive Polymers

Cited by 16 publications

References 339 publications

Fabrication of Photoresponsive Crystalline Artificial Muscles Based on PEGylated Covalent Organic Framework Membranes

Fabrication of Photoresponsive Crystalline Artificial Muscles Based on PEGylated Covalent Organic Framework Membranes

Oxidation-Sensitive Core–Multishell Nanocarriers for the Controlled Delivery of Hydrophobic Drugs

Hydrogels Classification According to the Physical or Chemical Interactions and as Stimuli-Sensitive Materials

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