Controlling the LCST-Phase Transition in Azobenzene-Functionalized Poly (N-Isopropylacrlyamide) Hydrogels by Light

Colaco, Ruchira; Appiah, Clement; Staubitz, Anne

doi:10.3390/gels9020075

Cited by 9 publications

(3 citation statements)

References 46 publications

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“…Under visible light irradiation, the corresponding physical and chemical properties of hydrogel can be changed due to reversible changes in the molecular structure, charge, and hydrophobicity of photoswitch. [81,82] Therefore, the photoisomerization process may be used to modify the crosslinking density, rheological characteristics, hydrophilicity, and structural features of hydrogels in order to accomplish reversible sol-gel transformation, intelligent drug release, and self-repair of hydrogels mediated by light. [83,84] Usually, the side chain part of the photoswitch is directly connected to the main chain of the polymerization.…”

Section: Photo-isomerization Hydrogelsmentioning

confidence: 99%

Photo‐Controllable Smart Hydrogels for Biomedical Application: A Review

Zhao,

Ran,

Lee

et al. 2023

Small Methods

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Nowadays, smart hydrogels are being widely studied by researchers because of their advantages such as simple preparation, stable performance, response to external stimuli, and easy control of response behavior. Photo‐controllable smart hydrogels (PCHs) are a class of responsive hydrogels whose physical and chemical properties can be changed when stimulated by light at specific wavelengths. Since the light source is safe, clean, simple to operate, and easy to control, PCHs have broad application prospects in the biomedical field. Therefore, this review timely summarizes the latest progress in the PCHs field, with an emphasis on the design principles of typical PCHs and their multiple biomedical applications in tissue regeneration, tumor therapy, antibacterial therapy, diseases diagnosis and monitoring, etc. Meanwhile, the challenges and perspectives of widespread practical implementation of PCHs are presented in biomedical applications. This study hopes that PCHs will flourish in the biomedical field and this review will provide useful information for interested researchers.

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Section: Photo-isomerization Hydrogelsmentioning

confidence: 99%

Photo‐Controllable Smart Hydrogels for Biomedical Application: A Review

Zhao,

Ran,

Lee

et al. 2023

Small Methods

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“…Nowadays, hydrogel actuators [1][2][3] have great development and potential applications in artificial muscle [4], grippers [5], soft robots [6], etc., on account of the soft and biocompatibility of the hydrogel. The hydrogel actuator can respond to single/multiple Gels 2023, 9, 428 2 of 17 stimulus such as pH [7,8], ionic strength [9,10], temperature [11][12][13], light [14,15], electricity [16] and magnetism [17]. The multiple stimuli-responsive [6] ability enables actuators more extensive applications, while the simple deformation behaviors can limit the development.…”

Section: Introductionmentioning

confidence: 99%

Polyurethane Shape Memory Polymer/pH-Responsive Hydrogel Hybrid for Bi-Function Synergistic Actuations

Peng

Cao

Sun

et al. 2023

Gels

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Stimuli-responsive actuating hydrogels response to the external stimulus with complex deformation behaviors based on the programmable anisotropic structure design are one of the most important smart soft materials, which have great potential applications in artificial muscles, smart values, and mini-robots. However, the anisotropic structure of one actuating hydrogel can only be programmed one time, which can only provide single actuating performance, and subsequently, has severely limited their further applications. Herein, we have explored a novel SMP/hydrogel hybrid actuator through combining polyurethane shape memory polymer (PU SMP) layer and pH-responsive polyacrylic-acid (PAA) hydrogel layer by a napkin with UV-adhesive. Owing to both the super-hydrophilicity and super-lipophilicity of the cellulose-fiber based napkin, the SMP and the hydrogel can be bonded firmly by the UV-adhesive in the napkin. More importantly, this bilayer hybrid 2D sheet can be programmed by designing a different temporary shape in heat water which can be fixed easily in cool water to achieve various fixed shapes. This hybrid with a fixed temporary shape can achieve complex actuating performance based on the bi-functional synergy of temperature-triggered SMP and pH-responsive hydrogel. The relatively high modulus PU SMP achieved high to 87.19% and 88.92% shape-fixing ratio, respectively, correspond to bending and folding shapes. The hybrid actuator can actuate with the 25.71 °/min actuating speed. Most importantly, one SMP/hydrogel bi-layer hybrid sheet was repeatedly programmed at least nine times in our research to fix various temporary 1D, 2D and 3D shapes, including bending, folding and spiraling shapes. As a result, only one SMP/hydrogel hybrid can provide various complex stimuli-responsive actuations, including the reversable bending-straightening, spiraling-unspiraling. A few of the intelligent devices have been designed to simulate the movement of the natural organisms, such as bio-mimetic “paw”, “pangolin” and “octopus”. This work has developed a new SMP/hydrogel hybrid with excellent multi-repeatable (≥9 times) programmability for high-level complex actuations, including the 1D to 2D bending and the 2D to 3D spiraling actuations, which also provides a new strategy to design other new soft intelligent materials and systems.

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“…Second, the shifts of T trans achieved have been mostly limited to a few degrees. 13,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] For many of the envisaged uses, this is too small. As an exception, Menzel and coworkers 32 succeeded to shift T trans of azobenzene-bearing polyacrylamides upon irradiation by up to 14 1C.…”

mentioning

confidence: 99%