scholarly journals Molecularly engineered switchable photo-responsive membrane in gas separation for environmental protection

2019 ◽  
Vol 25 (4) ◽  
pp. 447-461 ◽  
Author(s):  
Aishah Rosli ◽  
Siew Chun Low

In recent years, stimuli-responsive materials have garnered interest due to their ability to change properties when exposed to external stimuli, making it useful for various applications including gas separation. Light is a very attractive trigger for responsive materials due to its speedy and non-invasive nature as well as the potential to reduce energy costs significantly. Even though light is deemed as an appealing stimulus for the development of stimuli-responsive materials, this avenue has yet to be extensively researched, as evidenced by the fewer works done on the photo-responsive membranes. Of these, there are even less research done on photo-responsive materials for the purpose of gas separation, thus, we have collected the examples that answer both these criteria in this review. This review covers the utilisation of photo-responsive materials specifically for gas separation purposes. Photo-chromic units, their integration into gas separation systems, mechanism and research that have been done on the topic so far are discussed.

Author(s):  
Gore S. A. ◽  
Gholve S. B. ◽  
Savalsure S. M. ◽  
Ghodake K. B. ◽  
Bhusnure O. G. ◽  
...  

Smart polymers are materials that respond to small external stimuli. These are also referred as stimuli responsive materials or intelligent materials. Smart polymers that can exhibit stimuli-sensitive properties are becoming important in many commercial applications. These polymers can change shape, strength and pore size based on external factors such as temperature, pH and stress. The stimuli include salt, UV irradiation, temperature, pH, magnetic or electric field, ionic factors etc. Smart polymers are very promising applicants in drug delivery, tissue engineering, cell culture, gene carriers, textile engineering, oil recovery, radioactive wastage and protein purification. The study is focused on the entire features of smart polymers and their most recent and relevant applications. Water soluble polymers with tunable lower critical solution temperature (LCST) are of increasing interest for biological applications such as cell patterning, smart drug release, DNA sequencing etc.


2014 ◽  
Vol 34 (4) ◽  
pp. 310-314 ◽  
Author(s):  
Eujin Pei

Purpose – The purpose of this article is to reviews state-of-the-art developments in four-dimensional (4D) printing, discuss what it is, investigate new applications that have been discovered and suggest its future impact. Design/methodology/approach – The article clarifies the definition of 4D printing and describes notable examples covering material science, equipment and applications. Findings – This article highlights an emerging technology cycle where 4D printing research has gained traction within additive manufacturing. The use of stimuli-responsive materials can be programmed and printed to enable pre-determined reactions when subject to external stimuli. Originality/value – This article reviews state-of-the-art developments in 4D printing, discusses what it is, investigates new applications that have been discovered and suggests its future impact.


2014 ◽  
Vol 1622 ◽  
pp. 129-133
Author(s):  
Esha Das ◽  
Kazuaki Matsumura

ABSTRACTStimuli-responsive materials are capable of reversibly altering their properties depending on the environmental conditions or external stimuli. External stimuli typically include thermal, pH, electric fields, optical, magnetic fields, mechanical forces and chemical interactions. There are many instances in nature where responsive surfaces have been observed. Temperature is the most widely used stimulus in environmentally responsive polymer systems. The change of temperature is not only relatively easy to control, but also easily applicable both in vitro and in vivo. Temperature responsive polymers exhibit a phase transition at a certain temperature, which causes a sudden change in the solvation state. Polymers that become insoluble upon heating have a so-called lower critical solution temperature (LCST). One example of these polymers is poly (N-isopropyl acrylamide), which shows LCST at about 32 °C, close to the physiological temperature. In this study, we report the developing of novel polyampholytes which shows thermo-, salt-responsive liquid-liquid phase separation in aqueous solution.


2019 ◽  
Vol 48 (13) ◽  
pp. 3537-3549 ◽  
Author(s):  
Soren K. Mellerup ◽  
Suning Wang

Representative types of boron-based molecular systems that respond to external stimuli such as temperature, pressure, light, or chemicals (oxygen, acid, base etc.) are described in this review article. The boron molecules are classified according to their operating mechanisms, with emphasis on systems, which are based on switchable boron-donor bonds and switchable excited states.


2020 ◽  
Vol 12 (6) ◽  
pp. 168781402093340 ◽  
Author(s):  
Wei Liang ◽  
Hao Liu ◽  
Kunyang Wang ◽  
Zhihui Qian ◽  
Luquan Ren ◽  
...  

Biological muscles exhibit a high level of integration, in which actuators, sensors and transmission elements can be included in one component. Artificial muscles or actuators refer to intelligent stimuli-responsive materials that could reversibly deform with the trigger of various external stimuli. These materials, which have attracted tremendous attention, produce natural muscle-like actuation performance and show promising applications in robotics. After an introduction of various actuator technologies that contribute to robotic applications, a comparative analysis of the main actuation parameter is provided. The comprehensive comparisons of each kind of artificial muscle are summarised, and the promising properties that are required in robotics are presented, which highlight the development of their actuation performances and the challenges that limit their further employments. Future developmental prospects and perspectives of artificial actuators are discussed.


Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 608
Author(s):  
Zhenyu Xu ◽  
Yongsen Zhou ◽  
Baoping Zhang ◽  
Chao Zhang ◽  
Jianfeng Wang ◽  
...  

Millions of years’ evolution has imparted life on earth with excellent environment adaptability. Of particular interest to scientists are some plants capable of macroscopically and reversibly altering their morphological and mechanical properties in response to external stimuli from the surrounding environment. These intriguing natural phenomena and underlying actuation mechanisms have provided important design guidance and principles for man-made soft robotic systems. Constructing bio-inspired soft robotic systems with effective actuation requires the efficient supply of mechanical energy generated from external inputs, such as temperature, light, and electricity. By combining bio-inspired designs with stimuli-responsive materials, various intelligent soft robotic systems that demonstrate promising and exciting results have been developed. As one of the building materials for soft robotics, hydrogels are gaining increasing attention owing to their advantageous properties, such as ultra-tunable modulus, high compliance, varying stimuli-responsiveness, good biocompatibility, and high transparency. In this review article, we summarize the recent progress on plant-inspired soft robotics assembled by stimuli-responsive hydrogels with a particular focus on their actuation mechanisms, fabrication, and application. Meanwhile, some critical challenges and problems associated with current hydrogel-based soft robotics are briefly introduced, and possible solutions are proposed. We expect that this review would provide elementary tutorial guidelines to audiences who are interested in the study on nature-inspired soft robotics, especially hydrogel-based intelligent soft robotic systems.


Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 801
Author(s):  
Zhentao Hao ◽  
Weihua Li

The nepenthes-inspired lubricant-infused surface (LIS) is emerging as a novel repellent surface with self-healing, self-cleaning, pressure stability and ultra-slippery properties. Recently, stimuli-responsive materials to construct a smart LIS have broadened the application of LIS for droplet manipulation, showing great promise in microfluidics. This review mainly focuses on the recent developments towards the droplet manipulation on LIS with different mechanisms induced by various external stimuli, including thermo, light, electric, magnetism, and mechanical force. First, the droplet condition on LIS, determined by the properties of the droplet, the lubricant and substrate, is illustrated. Droplet manipulation via altering the droplet regime realized by different mechanisms, such as varying slipperiness, electrostatic force and wettability, is discussed. Moreover, some applications on droplet manipulation employed in various filed, including microreactors, microfluidics, etc., are also presented. Finally, a summary of this work and possible future research directions for the transport of droplets on smart LIS are outlined to promote the development of this field.


TECHNOLOGY ◽  
2016 ◽  
Vol 04 (04) ◽  
pp. 217-228 ◽  
Author(s):  
Papatya Kaner ◽  
Prity Bengani-Lutz ◽  
Ilin Sadeghi ◽  
Ayse Asatekin

Membrane technologies are essential for water treatment, bioprocessing and chemical manufacturing. Stimuli-responsive membranes respond to changes in feed conditions (e.g., temperature, pH) or external stimuli (e.g., magnetic field, light) with a change in performance parameters (permeability, selectivity). This enables new functionalities such as tunable performance, self-cleaning and smart-valve behavior. Polymer self-assembly is a crucial tool for manufacturing such membranes using scalable methods, enabling easier commercialization. This review surveys approaches to impart stimuli responsive behavior to membrane filters using polymer self-assembly.


Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6420
Author(s):  
Sreejith Sudhakaran Jayabhavan ◽  
Dipankar Ghosh ◽  
Krishna K. Damodaran

The structural modification of existing supramolecular architecture is an efficient strategy to design and synthesize supramolecular gels with tunable and predictable properties. In this work, we have modified bis(pyridyl urea) compounds with different linkers, namely hexylene and butylene, to their corresponding bis(pyridyl-N-oxide urea). The gelation properties of both the parent and the modified compounds were studied, and the results indicated that modification of the 3-pyridyl moieties to the corresponding 3-pyridyl-N-oxides induced hydrogelation. The stability of the parent and modified compounds were evaluated by sol-gel transition temperature (Tgel) and rheological measurements, and single-crystal X-ray diffraction was used to analyze the solid-state interactions of the gelators. The morphologies of the dried gels were analyzed by scanning electron microscopy (SEM), which revealed that the structural modification did not induce any prominent effect on the gel morphology. The stimuli-responsive behavior of these gels in the presence of salts in DMSO/water was evaluated by rheological experiments, which indicated that the modified compounds displayed enhanced gel strength in most cases. However, the gel network collapsed in the presence of the chloride salts of aluminum(III), zinc(II), copper(II), and cadmium(II). The mechanical strength of the parent gels decreased in the presence of salts, indicating that the structural modification resulted in robust gels in most cases. The modified compounds formed gels below minimum gel concentration in the presence of various salts, indicating salt-induced gelation. These results show the making and breaking ability of the gel network in the presence of external stimuli (salts), which explains the potential of using LMWGs based on N-oxide moieties as stimuli-responsive materials.


Author(s):  
Jae Gyeong Lee ◽  
Sukyoung Won ◽  
Jeong Eun Park ◽  
Jeong Jae Wie

Abstract The selective light absorption of pre-stretched thermoplastic polymeric films enables wireless photothermal shape morphing from two-dimensional Euclidean geometry of films to three-dimensional (3D) curvilinear architectures. For a facile origami-inspired programming of 3D folding, black inks are printed on glassy polymers that are used as hinges to generate light-absorption patterns. However, the deformation of unpatterned areas and/or stress convolution of patterned areas hinder the creation of accurate curvilinear structures. In addition, black inks remain in the film, prohibiting the construction of transparent 3D architectures. In this study, we demonstrate the facile preparation of transparent 3D curvilinear structures with the selection of the curvature sign and chirality via the selective light absorption of detachable tapes. The sequential removal of adhesive patterns allowed sequential folding and the control of strain responsivity in a single transparent architecture. The introduction of multiple heterogeneous non-responsive materials increased the complexity of strain engineering and functionality. External stimuli responsive kirigami-based bridge triggered the multi-material frame to build the Gaussian curvature. Conductive material casted on the film in a pattern retained the conductivity, despite local deformation. This type of tape patterning system, adopting various materials, can achieve multifunction including transparency and conductivity.


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