A Highly Conductive, Self-Recoverable, and Strong Eutectogel of a Deep Eutectic Solvent with Polymer Crystalline Domain Regulation.
07 Nov 2021-ACS Applied Materials & Interfaces (American Chemical Society (ACS))-Vol. 13, Iss: 45, pp 54409-54416
TL;DR: In this article, a physically cross-linked eutectogel based on a polyvinyl alcohol/poly(acrylic acid) (PVA/PAA) binary polymer skeleton and a deep Eutectic solvent (DES) was developed.
Abstract: It is desirable to fabricate an antifatigue gel for skin-mimicking sensors on the demand of long-term durability in practical usage. Here, we developed a physically cross-linked eutectogel based on a poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) binary polymer skeleton and a deep eutectic solvent (DES). In this eutectogel, uniformly distributed PVA crystalline domains acted as stable physical cross-linkers, and high-density hydrogen bonds possessed great reversibility. Such a polymer network structure was expected to endow this eutectogel with excellent mechanical strength, stretchability, and a self-recovery ability. Specifically, this eutectogel exhibited a superior tensile strength of 2.6 MPa, a fracture strain of 680%, and a fracture toughness of 8.39 MJ m-3. In cyclic stretching/releasing tests with a fixed strain of 100%, this eutectogel could recover its mechanical properties within a 600 s resting time. Based on this self-recoverable eutectogel, a reliable flexible sensor was fabricated, which possessed good sensitivity and stability over a wide strain range (1-300%). More importantly, the flexile sensor was able to maintain a highly repeatable response signal during 1000 consecutive stretching/releasing cycles, showing outstanding long-term durability. Given the excellent sensing performance, this eutectogel has promising potential in wearable electronics, human-machine systems, and soft robotics.
Citations
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TL;DR: In this paper , a solvent replacement approach was proposed to regulate the spatiotemporal expression of intra/interpolymer interactions to prepare strong and tough physical eutectogels.
Abstract: Physical eutectogels are appealing materials for technological devices due to their superior ionic conductivity, thermal and electrochemical stability, non‐volatility, and low cost. Nevertheless, current physical eutectogels are suffering from weak mechanical strength and toughness. Here, taking advantage of the distribution difference of polyvinyl alcohol (PVA) in water and deep eutectic solvents (DESs), a simple and universal solvent‐replacement approach is proposed to regulate the spatiotemporal expression of intra/interpolymer interactions to prepare strong and tough physical eutectogels. The exchange of DESs with water can restrengthen the weakened interactions between PVA chains in water, enabling PVA to crystallize to construct a uniform and robust polymer network. Consequently, the resultant PVA eutectogel exhibits record‐high strength (20.2 MPa), toughness (62.7 MJ m–3), and tear‐resistance (tearing energy Σ42.4 kJ m–2), while possessing excellent stretchability (Σ550% strain), repairability, and adhesive performance. Furthermore, this strategy is proven to be universally applicable to various species of polymers, and even can be utilized to fabricate continuous and conductive eutectogel fibers, demonstrating potential as engineering materials and wearable sensors.
23 citations
TL;DR: In this paper , peptide-enhanced eutectic gels were synthesized by introducing α-helical "molecular spring" structure into deep EUTectic solvent, achieving high tensile/compression, good resilience, superior fracture toughness, excellent fatigue resistance and strong adhesion.
Abstract: Abstract Natural gels and biomimetic hydrogel materials have been able to achieve outstanding integrated mechanical properties due to the gain of natural biological structures. However, nearly every natural biological structure relies on water as solvents or carriers, which limits the possibility in extreme conditions, such as sub-zero temperatures and long-term application. Here, peptide-enhanced eutectic gels were synthesized by introducing α-helical “molecular spring” structure into deep eutectic solvent. The gel takes full advantage of the α-helical structure, achieving high tensile/compression, good resilience, superior fracture toughness, excellent fatigue resistance and strong adhesion, while it also inherits the benefits of the deep eutectic solvent and solves the problems of solvent volatilization and freezing. This enables unprecedentedly long and stable sensing of human motion or mechanical movement. The electrical signal shows almost no drift even after 10,000 deformations for 29 hours or in the −20 °C to 80 °C temperature range.
16 citations
TL;DR: In this paper , the authors highlight the potential of monomers containing hydrogen-bond acceptor groups, and the obtained polymer can form hydrogen bonding networks with deep eutectic solvents (DESs), thus endowing the polymer with self-healing and adhesive properties.
12 citations
TL;DR: In this article , a flexible and stretchable sensor based on highly conductive ionic gel is developed, which can detect multiple mechanical deformation modes to allow for detections of strain, pressure, and torsion on a single device.
Abstract: Recently, flexible sensors have attracted great interest for their promising application in wearable electronics. However, previous mechanical sensors are typically limited to detecting one type of stimulus and monotonous in color, which are not able to meet the sensing nor fashion requirements by customers who will wear them in daily life. Herein, a flexible and stretchable sensor based on highly conductive ionic gel is developed. Different phosphor nanoparticles are uniformly embedded into gel to enable color‐customization and even self‐illumination depending on preference. The gel is also self‐healable after complete severance and degradable in hot water. The sensors can detect multiple mechanical deformation modes to allow for detections of strain, pressure, and torsion on a single device. Wearable sensing prototypes are demonstrated with attachment to different parts of human body to detect various human motions, including strain sensing for frowning and elbow/knee bending, pressure sensing for vocal cord vibrations and pulse at wrist, and torsion sensing for shoulder and forearm rotations, through an in‐house, wireless, real‐time signal transmission and process system. Considering its sensing capability toward different stimuli as well as superior physical properties, the developed color‐customizable and self‐illuminating ionic gel sensor would find its promising applications toward wearable sensing.
9 citations
TL;DR: In this paper , the authors used the flexible material hydrogel as electrode and electrolyte to design an all-hydrogel integrated flexible supercapacitor, which has excellent mechanical and electrical properties.
4 citations
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TL;DR: A carbonized plain-weave silk fabric is fabricated into wearable and robust strain sensors, which can be stretched up to 500% and show high sensitivity in a wide strain range.
Abstract: A carbonized plain-weave silk fabric is fabricated into wearable and robust strain sensors, which can be stretched up to 500% and show high sensitivity in a wide strain range. This sensor can be assembled into wearable devices for detection of both large and subtle human activities, showing great potential for monitoring human motions and personal health.
711 citations
TL;DR: A deeper understanding of the fundamental challenges faced for wearable sensors and of the state-of-the-art for wearable sensor technology, the roadmap becomes clearer for creating the next generation of innovations and breakthroughs.
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