Colloid Surfactants for Emulsion Stabilization Kim, Jin-Woong; Lee, Daeyeon; Shum, Ho Cheung ...
Advanced materials (Weinheim),
September 3, 2008, Letnik:
20, Številka:
17
Journal Article
Recenzirano
Colloid surfactants are fabricated with precisely controlled geometry and used for emulsion stabilization. These amphiphilic dimer particles (left) combine the benefits of emulsion stabilization of ...particles and the amphiphilicity of molecular surfactants to afford better emulsion stabilization. Remarkably, these colloidal surfactants stabilize not only spherical emulsion droplets but also nonspherical ones (right).
Electronic skin (E‐skin) imitates human skin by converting external stimuli into electrical signals. E‐skin requires high flexibility and a high level of device integration. Unlike conventional ...E‐skin creation methods, a highly sensitive pressure sensor matrix (100 pixels cm−2) made of position‐registered elastic conductive microparticles (MPs) is created. The MPs form a Schottky junction with the bottom electrode and the current through the junction is sensitive to external pressure, forming a simple one‐selector two‐terminal device array. The Schottky junction eliminates the electrical cross talks between the sensor pixels consisting of 64 MPs in each. The flexible pressure sensor matrix is used as an artificial fingertip for Braille reading and as an electronic scale based on detailed force distribution. This work opens up the possibility that assembled MPs, which have been a long‐standing research topic in academia, can be used to make practical electronic devices.
A new strategy to fabricate a pressure‐sensitive selector based on assembled microparticles is presented. Highly ordered large‐area microparticle arrays assembled through a physicochemical template become pixelated pressure‐sensitive diodes for a tactile sensor matrix. Each particle responses to the applied pressure and rectifies the current for cross talk inhibition at the same time.
Biphasic Janus particles with a precisely tunable internal morphology are fabricated using a novel, versatile, and robust technique. This technique can be used in conjunction with microfluidics to ...produce monodisperse particles, or can be combined with bulk emulsification techniques to produce large quantities of particles.
High‐resolution 3D‐printable hydrogels with high mechanical strength and biocompatibility are in great demand because of their potential applications in numerous fields. In this study, a material ...system comprising Pluronic F‐127 dimethacrylate (FDMA) is developed to function as a direct ink writing (DIW) hydrogel for 3D printing. FDMA is a triblock copolymer that transforms into micelles at elevated temperatures. The transformation increases the viscosity of FDMA and preserves its structure during DIW 3D printing, whereupon the printed structure is solidified through photopolymerization. Because of this viscosity shift, various functionalities can be incorporated through the addition of other materials in the solution state. Acrylic acid is incorporated into the pregel solution to enhance the mechanical strength, because the carboxylate group of poly(acrylic acid) ionically crosslinks with Fe3+, increasing the toughness of the DIW hydrogel 37 times to 2.46 MJ m−3. Tough conductive hydrogels are also 3D printed by homogenizing poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate into the pregel solution. Furthermore, the FDMA platform developed herein uses DIW, which facilitates multicartridges 3D printing, and because all the materials included are biocompatible, the platform may be used to fabricate complex structures for biological applications.
In this work, Pluronic F‐127 dimethacrylate is evaluated as a platform for extrusion hydrogel 3D printing. The platform can be incorporated with additional materials to achieve specific functionalities such as enhanced mechanical strength and conductivity. The platform is also biocompatible, which makes it promising for the fabrication of complex structures for biological applications by 3D printing.
A facile and scalable synthesis of mesoporous films impregnated with Au nanoparticles (NPs) as effective dielectrics is demonstrated for enhancing the nanogenerator performance based on vertical ...contact-separation mode. This technique is so simple and scalable, providing a promising solution for developing large-scale and practical self-powered devices. The spatial distribution of Au NPs made it possible to fabricate an Au NP-embedded mesoporous triboelectric nanogenerator (AMTENG) with a high output power of 13 mW under cycled compressive force, giving over 5-fold power enhancement, compared with a flat film-based TENG under the same mechanical force. It is proposed that the presence of aligned dipoles produced due to the charges created by the contact between Au NPs and PDMS inside the pores can influence the surface potential energy of mesoporous films. With such an enhanced power output and unique device design, we demonstrate various applications such as self-powered shape mapping sensors, foot-step driven large-scale AMTENGs, and integrated circuits with capacitors for powering commercial cell phones for realizing self-powered systems from footsteps, wind power, and ocean waves.
Media exposed to atmospheric pressure plasma (APP) produce reactive oxygen and nitrogen species (RONS), with hydrogen peroxide (H
O
), nitrite (NO
), and nitrate (NO
) being among the most detected ...species due to their relatively long lifetime. In this study, a standardized microwave-excited (ME) APP jet (APPJ) source was employed to produce gaseous RONS to treat liquid samples. The source was a commercially available plasma jet, which generated argon plasma utilizing a coaxial transmission line resonator at the operating frequency of 2.45 GHz. An ultraviolet-visible spectrophotometer was used to measure the concentrations of H
O
and NO
in plasma-activated media (PAM). Three different types of media (deionized water, Hank's balanced salt solution, and cell culture solution Dulbecco's modified eagles medium DMEM) were utilized as liquid samples. Among these media, the plasma-treated DMEM was observed to have the highest levels of H
O
and NO
. Subsequently, the feasibility of using argon ME-APPJ-activated DMEM (PAM) as an adjuvant to enhance the therapeutic effects of cisplatin on human bladder cancer cells (T-24) was investigated. Various cancer cell lines, including T-24 cells, treated with PAM were observed in vitro for changes in cell viability using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. A viability reduction was detected in the various cancer cells after incubation in PAM. Furthermore, the study's results revealed that PAM was effective against cisplatin-resistant T-24 cells in vitro. In addition, a possible connection between HER expression and cell viability was sketched.
Responsive colloidal polymer particles with well‐defined shapes and ordered internal mesostructures are attracting increasing attention because of their potential applications in sensors, catalysis, ...nano‐drug carriers, color pigments, and others. Recently, 3D confined assembly of block copolymers in emulsion droplets has emerged as a promising method for fabrication of colloidal polymer particles with controllable shapes and internal structures. In this paper, the recent advances in engineering anisotropically shaped and internally ordered colloidal polymer particles are summarized, followed by highlighting their stimuli‐responsiveness and emerging applications. In the last section, the current challenges and future opportunities in this fast growing research field are discussed.
This review highlights recent advances in the design of responsive colloidal polymer particles with well‐defined shapes and ordered internal mesostructures, followed by reviewing their stimuli‐responsiveness and emerging applications. Finally, the challenging issues associated with current synthetic methods and future directions in this growing research field are presented.
Wound closure is a critical step in postoperative wound recovery. Substantial advancements have been made in many different means of facilitating wound closure, including the use of tissue adhesives. ...Compared to conventional methods, such as suturing, tissue bioadhesives better accelerate wound closure. However, several existing tissue adhesives suffer from cytotoxicity, inadequate tissue adhesive strength, and high costs. In this study, a series of bioadhesives was produced using non-swellable spider silk-derived silk fibroin protein and an outer layer of swellable polyethylene glycol and tannic acid. The gelation time of the spider silk-derived silk fibroin protein bioadhesive is less than three minutes and thus can be used during rapid surgical wound closure. By adding polyethylene glycol (PEG) 2000 and tannic acid as co-crosslinking agents to the N-Hydroxysuccinimide (NHS), and 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) reaction, the adhesive strength of the bioadhesive became 2.5 times greater than that of conventional fibrin glue adhesives. Silk fibroin bioadhesives do not show significant cytotoxicity in vitro compared with other bioadhesives. In conclusion, silk fibroin bioadhesive is promising as a new medical tool for more effective and efficient surgical wound closure, particularly in bone fractures.
Highly stretchable 2D fabrics are prepared by weaving fibers for a fabric-structured triboelectric nanogenerator (FTENG). The fibers mainly consist of Al wires and polydimethylsiloxane (PDMS) tubes ...with a high-aspect-ratio nanotextured surface with vertically aligned nanowires. The fabrics were produced by interlacing the fibers, which was bonded to a waterproof fabric for all-weather use for fabric-structured triboelectric nanogenerator (FTENG). It showed a stable high-output voltage and current of 40 V and 210 μA, corresponding to an instantaneous power output of 4 mW. The FTENG also exhibits high robustness behavior even after 25% stretching, enough for use in smart clothing applications and other wearable electronics. For wearable applications, the nanogenerator was successfully demonstrated in applications of footstep-driven large-scale power mats during walking and power clothing attached to the elbow.
This study introduces a Janus colloid surfactant catalyst platform exhibiting remarkable catalytic activity and magnetic responsiveness in Pickering emulsion microreactors. The patching of catalytic ...nanoparticles (NPs) such as Pd NPs and Ag NPs on amphiphilic Janus microparticles (JMPs) permits the control of catalytic activity for the organic reactions occurring in emulsion droplets. Through model organic reactions including oxidation, amination, and reduction, we show that the JMP catalysts assemble at the reactant–water interface of Pickering emulsions and play an essential role in enhancing the reaction kinetics and product yields. Moreover, when Fe 2 O 3 NPs were co-patched site specifically, the Pickering emulsion droplets showed magnetic responsiveness, thus leading to facile recovery of products and effective recycling of JMP catalysts. The colloid surfactant catalysts developed in our study are expected to advance the environment-friendly catalyst system for green chemistry.
