• Environmental Engineering Research
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• v.25 no.4
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• pp.447-461
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• 2020

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.

• Polymer(Korea)
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• v.35 no.1
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• pp.94-98
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• 2011

Poly(2-hydroxyethyl methacrylate), PHEMA, hybrid gels containing Pluronic and acrylic acid (AAc) were prepared as new biocompatible and stimuli-responsive hydrogels by photo-polymerization technique. The prepared hybrid gel showed reversible, temperature-responsive swelling behavior due to the presence of Pluronic component, which underwent sol-gel transition at an elevated temperature to cause gel shrinkage. The hydrogel also exhibited increased swelling degrees and pH-sensitivity due to the AAc component with ionizable carboxylic acid groups. The microporous gel morphology and its changes upon stimuli was observed by scanning electron microscopy.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.261-261
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• 2010

Photonic band gap (PBG) materials have been of great interest due to their potential applications in science and technology. Their applications can be further extended when PBG becomes tunable against various chemical and electrical stimuli. In recent, it was found that tunable photonic band gap materials can be achieved by incorporating stimuli-responsive smart gels into PBG materials. For example, the characteristic volume phase transition of gels in response to the various external stimuli including temperature, pH, ionic strength, solvent compositions and electric field were recently combined with the unique optical properties of photonic crystals to form unprecedented highly responsive optical components. Since these responsive photonic crystals are capable of reversibly converting chemical or electrical energy into characteristic optical signals, they have been considered as a good platform for label-free chemical or biological detection, actuators or optical switches as well as a model system for investigating gel swelling behavior. Herein, we report block copolymer photonic gels self-assembled from polystyrene-b-poly (2-vinyl pyridine) (PS-b-P2VP) block copolymers. In this talk, we are going to demonstrate that selective swelling of lamellar structure can be effectively utilized for fabricating PBG materials with extremely large tunability. Optical properties and their applications will be discussed.

• Smart Structures and Systems
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• v.7 no.3
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• pp.185-198
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• 2011

The promise of biomimetic smart structures that can function as sensors and actuators in biomedicine is enormous. Technological development in the field of stimuli-responsive shape memory polymers have opened up a new avenue of applications for polymer-based synthetic actuators. Such synthetic actuators mimic various attributes of living organisms including responsiveness to stimuli, shape memory, selectivity, motility, and organization. This article briefly reviews various stimuli-responsive shape memory polymers and their application as bioactuators. Although the technological advancements have prototyped the potential applications of these smart materials, their widespread commercialization depends on many factors such as sensitivity, versatility, moldability, robustness, and cost.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.550-551
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• 2012

Physically responsive field-effect transistors (physi-FETs), which are sensitive to physical stimuli, have been studied for decades. However, the primary issue of separating responses by sensing materials from interferences by other subcomponents in a FET transducer under global physical stimuli has not been completely resolved. Recent challenges of structural design and employing smart materials with a large electro-physical coupling effect for flexible physi-FETs still remain. In this article, we propose directly integrating nanocomposites of barium titanate (BT) nanoparticles (NPs) and highly crystalline poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) as gate dielectrics into flexible organic FETs to precisely separate and quantify tiny variations of remnant polarization caused by mechanical stimuli. Investigations under static stimuli resulted in first-reported giant-positive piezoelectric coefficients of d33 up to 960 pC/N, presumably due to significant contribution of the intrinsic piezoelectricity of BT NPs and P(VDF-TrFE) crystallites. This approach provides a general research direction, and not limited to physic-FETs.

• Journal of Pharmaceutical Investigation
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• v.25 no.3
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• pp.1-6
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• 1995

• Polymer Science and Technology
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• v.22 no.3
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• pp.248-255
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• 2011

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.147-154
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• 2018

Currently, to overcome low therapeutic efficiencies and side effects of anticancer agents, the study of drug carrier based on polymers have been consistently investigated. Although the traditional drug carrier based on polymers displayed an excellent result and significant progress, there has been a problem with the side effect and low therapeutic efficiency because of the premature drug release before reached to the targeted region by the low stability in blood stream and sustained drug release. In this review article, to improve the problem of inefficient drug release, methods were suggested, which can maximize the therapeutic efficiency by increasing the stability in the blood stream and triggering drug release at the target site by introducing a stimuli-responsive substance to the non-toxic and biocompatible natural polymer chitosan.

• Journal of Sensor Science and Technology
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• v.26 no.1
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• pp.35-38
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• 2017

A thermally responsive hydrogel has reversibility with temperature during swelling. Here, we proposed origami inspired temperature sensor by using multi-layered hydrogel film. The formation of patterned stripes on microscale film drives bending to an angle that can be controlled linearly. Although temperature range was not wide, measured sensitivity of sensors has high resolution and accuracy. It providing a powerful platform for the design of sensitive sensors and that easily adapt other type of sensors in microscale.

• Journal of the Korean Applied Science and Technology
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• v.32 no.2
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• pp.202-214
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• 2015

Stimuli-responsive biomaterials that alter their function through sensing local molecular cues may enable technological advances in the fields of drug delivery, gene delivery, actuators, biosensors, and tissue engineering. In this research, pH-responsive hydrogel which is comprised of dimethylaminoethyl methacylate (DMAEMA) and 2-hydroxyethyl methacrylate (HEMA) was synthesized for the effective delivery of doxorubicin (Dox) to breast cancer cells. Cancer and tumor tissues show a lower extracellular pH than normal tissues. DMAEMA/HEMA hydrogels showed significant sensitivity by small pH changes and each formulation of hydrogels was examined by scanning electron microscopy, mechanical test, equilibrium mass swelling, controlled Dox release, and cytotoxicity. High swelling ratios and Dox release were obtained at low pH buffer condition, low cross-linker concentration, and high content of DMAEMA. Dox release was accelerated to 67.3% at pH 5.5 for 6-h incubation at $37^{\circ}C$, while it was limited to 13.8% at pH7.4 at the same time and temperature. Cell toxicity results to breast cancer cells indicate that pH-responsive DMAEMA/HEMA hydrogels may be used as an efficient matrix for anti-cancer drug delivery with various transporting manners. Also, pH-responsive DMAEMA/HEMA hydrogels may be useful in therapeutic treatment which is required a triggered release at low pH range such as gene delivery, ischemia, and diabetic ketoacidosis.