A series of hydrogel‐based inks are developed to print 3D structures capable of reversible shape deformation in response to hydration and temperature. The inks are made of large polymer chains and UV ...curable monomers which form interpenetrating polymer networks after polymerization. By taking advantage of the long polymer chains in the ink formulations, it is possible to adjust the rheological properties of the inks to enable 3D printing. Hydrogels produced from the inks exhibit robust mechanical performance with their mechanical properties controlled by the nature of the long polymer chains within their networks. In this paper, hydrogel hinges are made from various ink formulations and a simple model is developed to predict their bending characteristics, including the bending curvature and bending angle. This model can be used as a guide to determine optimal parameters for a wide range of materials combination to create all‐hydrogel structures that undergo desired shape transitions.
4D printed hybrid hydrogels capable of reversible shape transition in response to hydration and temperature are prepared. The shape deformation of printed hydrogel sheets is determined by the print design and the constituting hydrogels properties. The latter is controlled by the development of tailored inks.
Upon flowing hot steam over hexagonal boron nitride (h‐BN) bulk powder, efficient exfoliation and hydroxylation of BN occur simultaneously. Through effective hydrogen bonding with water and ...N‐isopropylacrylamide, edge‐hydroxylated BN nanosheets dramatically improve the dimensional change and dye release of this temperature‐sensitive hydrogel and thereby enhance its efficacy in bionic, soft robotic, and drug‐delivery applications.
Mimicking the natural actuating systems artificially provides ample opportunities in the field of soft robotics. In this domain, recent advancements in tough hydrogels along with advanced ...manufacturing techniques have offered us new tools for creating hybrid and soft artificial muscles that resemble the attributes of natural muscles and biological organisms. This review article provides a summary of the recent developments in the field of hydrogel-based actuators and soft artificial muscles and presents a current account of their emerging applications. Further, the fundamentals behind the actuation of hydrogels are discussed with a focus on hydrogels swelling, diffusion, and mechanical behaviour. The design details of different tough hydrogel systems are highlighted, and their physical and mechanical properties are quantitatively compared with biological tissues. Finally, a brief conclusion is provided with remarks on the remaining challenges in this field.
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•In-depth overview of hydrogel-based actuators, focusing on their fundamental attributes necessary for robotic systems.•Providing a comprehensive comparison between tough hydrogels and soft tissues as a selection guide for soft robotics.•Details of the new ground-breaking innovations taken place in the field of soft robotic systems based on tough hydrogels.
Breast cancer is the most common and biggest health threat for women. There is an urgent need to develop novel breast cancer therapies to overcome the shortcomings of conventional surgery and ...chemotherapy, which include poor drug efficiency, damage to normal tissues, and increased side effects. Drug delivery systems based on injectable hydrogels have recently gained remarkable attention, as they offer encouraging solutions for localized, targeted, and controlled drug release to the tumor site. Such systems have great potential for improving drug efficiency and reducing the side effects caused by long-term exposure to chemotherapy. The present review aims to provide a critical analysis of the latest developments in the application of drug delivery systems using stimuli-responsive injectable hydrogels for breast cancer treatment. The focus is on discussing how such hydrogel systems enhance treatment efficacy and incorporate multiple breast cancer therapies into one system, in response to multiple stimuli, including temperature, pH, photo-, magnetic field, and glutathione. The present work also features a brief outline of the recent progress in the use of tough hydrogels. As the breast undergoes significant physical stress and movement during sporting and daily activities, it is important for drug delivery hydrogels to have sufficient mechanical toughness to maintain structural integrity for a desired period of time.
Artificial Muscles from Fishing Line and Sewing Thread Haines, Carter S.; Lima, Márcio D.; Li, Na ...
Science (American Association for the Advancement of Science),
02/2014, Letnik:
343, Številka:
6173
Journal Article
Recenzirano
The high cost of powerful, large-stroke, high-stress artificial muscles has combined with performance limitations such as low cycle life, hysteresis, and low efficiency to restrict applications. We ...demonstrated that inexpensive high-strength polymer fibers used for fishing line and sewing thread can be easily transformed by twist insertion to provide fast, scalable, nonhysteretic, long-life tensile and torsional muscles. Extreme twisting produces coiled muscles that can contract by 49%, lift loads over 100 times heavier than can human muscle of the same length and weight, and generate 5.3 kilowatts of mechanical work per kilogram of muscle weight, similar to that produced by a jet engine. Woven textiles that change porosity in response to temperature and actuating window shutters that could help conserve energy were also demonstrated. Large-stroke tensile actuation was theoretically and experimentally shown to result from torsional actuation.
A new type of absorption‐powered artificial muscle provides high performance without needing a temperature change. These muscles, comprising coiled carbon nanotube fibers infiltrated with silicone ...rubber, can contract up to 50% to generate up to 1.2 kJ kg−1. The drive mechanism for actuation is the rubber swelling during exposure to a nonpolar solvent. Theoretical energy efficiency conversion can be as high as 16%.
•A small hydraulic McKibben muscle with high efficiency is proposed.•Effect of the bladder stiffness on muscle performance is studied.•A new and more accurate equation to predict the muscle ...performances is proposed.•A sealed actuation system suitable for robotic machines with low voltage water pump is introduced.
Fluidic McKibben artificial muscles are one of the most popular biomimetic actuators, showing similar static and dynamic performance to skeletal muscles. In particular, their pneumatic version offers high-generated force, high speed and high strain in comparison to other actuators. This paper investigates the development of a small-size, fully enclosed, hydraulic McKibben muscle powered by a low voltage pump. Hydraulic McKibben muscles with an outside diameter of 6mm and a length ranging from 35mm to 80mm were investigated. These muscles are able to generate forces up to 26N, strains up to 23%, power to mass of 30W/kg and tension intensity of 1.78N/mm2 at supply water pressure of 2.5bar. The effects of injected pressure and inner tube stiffness on the actuation strain and force generation were studied and a simple model introduced to quantitatively estimate force and stroke generated for a given input pressure. This unique actuation system is lightweight and can be easily modified to be employed in small robotic systems where large movements in short time are required.
Here, we show that graphene oxide (GO) dispersions exhibit unique viscoelastic properties, making them a new class of soft materials. The fundamental insights accrued here provide the basis for the ...development of fabrication protocols for these two-dimensional soft materials, in a diverse array of processing techniques.
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