scholarly journals Effect of mesoscale phase contrast on fatigue-delaying behavior of self-healing hydrogels

2021 ◽  
Vol 7 (16) ◽  
pp. eabe8210
Author(s):  
Xueyu Li ◽  
Kunpeng Cui ◽  
Takayuki Kurokawa ◽  
Ya Nan Ye ◽  
Tao Lin Sun ◽  
...  
Keyword(s):  
Crack Growth ◽  
Fatigue Resistance ◽  
Phase Contrast ◽  
Stress Singularity ◽  
Soft Materials ◽  
Self Healing ◽  
Strong Phase ◽  
Mesoscale Structure ◽  
High Fatigue ◽  
Affine Deformation

We investigate the fatigue resistance of chemically cross-linked polyampholyte hydrogels with a hierarchical structure due to phase separation and find that the details of the structure, as characterized by SAXS, control the mechanisms of crack propagation. When gels exhibit a strong phase contrast and a low cross-linking level, the stress singularity around the crack tip is gradually eliminated with increasing fatigue cycles and this suppresses crack growth, beneficial for high fatigue resistance. On the contrary, the stress concentration persists in weakly phase-separated gels, resulting in low fatigue resistance. A material parameter, λtran, is identified, correlated to the onset of non-affine deformation of the mesophase structure in a hydrogel without crack, which governs the slow-to-fast transition in fatigue crack growth. The detailed role played by the mesoscale structure on fatigue resistance provides design principles for developing self-healing, tough, and fatigue-resistant soft materials.

Development of a multifunctional nanocomposite film with record-high ultralow temperature toughness and unprecedented fatigue-resistance

2021 ◽  
Author(s):  
Shuaicheng Jiang ◽  
Yanqiang Wei ◽  
Jiongjiong Li ◽  
Xiaona Li ◽  
Kaili Wang ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Spider Silk ◽  
Soybean Protein ◽  
Scale Up ◽  
Poly Vinyl Alcohol ◽  
Polar Regions ◽  
Self Healing ◽  
Fluorescent Properties ◽  
Soybean Protein Isolate ◽  
Ultralow Temperature

Abstract In the quest of materials that can tolerate extreme environments (i.e., aerospace, polar regions of earth), facile design of self-healing, high fatigue-resistant and multifunctional nanocomposite materials with excellent ultralow temperature toughness, especially by utilizing inexpensive and sustainable bioresources is still currently challengeable. In current study, we present a material that displays remarkable ultralow temperature toughness, shows excellent toughness (107.3 MJ·m-3) at − 196°C and maintains high mechanical strength in highly humid environments. This material is a spider silk-inspired, poly(vinyl alcohol) (PVA)-based, autonomous room temperature self-healable nanocomposite by complexation of boron nitride (BN), quantum dots (QDs) and soybean protein isolate grafted lignin (SPI-lignin). The fabricated material, namely PVA-BN-QDs-SPI-lignin, simultaneously exhibits outstanding tensile strength (53.3 MPa), toughness (182.8 MJ·m-3), fatigue-resistance as well as antiultraviolet and fluorescent properties and sets an impressive new record of folding-failure (900 000 times) and toughness, which are 10.6 to 45.7 times higher than other graphene-based nanocomposites. It can be impressively self-healed within only 2 minutes. Of particular interest is its facile, green, mild and inexpensive preparation method that can be easily scale up. It is believed that this work, beginning with abundant biodegradable resources, opens the door to develop biobased multifunctional materials in practical applications, such as flexible wearable materials.

scholarly journals Applications of Phase-Contrast STEM as Dose Efficient Method for High-resolution Imaging of Soft Materials

2020 ◽  
Vol 26 (S2) ◽  
pp. 2158-2160
Author(s):  
Roberto dos Reis ◽  
Anahita Pakzad ◽  
Paul Smeets ◽  
Vinayak Dravid
Keyword(s):  
High Resolution ◽  
Efficient Method ◽  
Phase Contrast ◽  
Soft Materials ◽  
High Resolution Imaging ◽  
Resolution Imaging

scholarly journals Mesoscale bicontinuous networks in self-healing hydrogels delay fatigue fracture

2020 ◽  
Vol 117 (14) ◽  
pp. 7606-7612 ◽  
Author(s):  
Xueyu Li ◽  
Kunpeng Cui ◽  
Tao Lin Sun ◽  
Lingpu Meng ◽  
Chengtao Yu ◽  
...  
Keyword(s):  
Fatigue Fracture ◽  
Polymer Network ◽  
Hierarchical Structures ◽  
Soft Materials ◽  
Biological Tissues ◽  
Crack Advance ◽  
Self Healing ◽  
Hard Phase ◽  
Soft Phase ◽  
Simple Model System

Load-bearing biological tissues, such as muscles, are highly fatigue-resistant, but how the exquisite hierarchical structures of biological tissues contribute to their excellent fatigue resistance is not well understood. In this work, we study antifatigue properties of soft materials with hierarchical structures using polyampholyte hydrogels (PA gels) as a simple model system. PA gels are tough and self-healing, consisting of reversible ionic bonds at the 1-nm scale, a cross-linked polymer network at the 10-nm scale, and bicontinuous hard/soft phase networks at the 100-nm scale. We find that the polymer network at the 10-nm scale determines the threshold of energy release rateG0above which the crack grows, while the bicontinuous phase networks at the 100-nm scale significantly decelerate the crack advance until a transitionGtranfar aboveG0. In situ small-angle X-ray scattering analysis reveals that the hard phase network suppresses the crack advance to show decelerated fatigue fracture, andGtrancorresponds to the rupture of the hard phase network.

Multi-Arch-Structured All-Carbon Aerogels with Superelasticity and High Fatigue Resistance as Wearable Sensors

2020 ◽  
Vol 12 (14) ◽  
pp. 16822-16830 ◽  
Author(s):  
Jiankun Huang ◽  
Jingbin Zeng ◽  
Baoqiang Liang ◽  
Junwei Wu ◽  
Tongge Li ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Wearable Sensors ◽  
Carbon Aerogels ◽  
High Fatigue

scholarly journals Smart polymers for cell therapy and precision medicine

2019 ◽  
Vol 26 (1) ◽  
Author(s):  
Hung-Jin Huang ◽  
Yu-Liang Tsai ◽  
Shih-Ho Lin ◽  
Shan-hui Hsu
Keyword(s):  
3D Printing ◽  
Cell Therapy ◽  
Shape Memory ◽  
Precision Medicine ◽  
Environmental Changes ◽  
Memory Performance ◽  
Soft Materials ◽  
Smart Polymers ◽  
Self Healing ◽  
Thermally Responsive

Abstract Soft materials have been developed very rapidly in the biomedical field over the past 10 years because of advances in medical devices, cell therapy, and 3D printing for precision medicine. Smart polymers are one category of soft materials that respond to environmental changes. One typical example is the thermally-responsive polymers, which are widely used as cell carriers and in 3D printing. Self-healing polymers are one type of smart polymers that have the capacity to recover the structure after repeated damages and are often injectable through needles. Shape memory polymers are another type with the ability to memorize their original shape. These smart polymers can be used as cell/drug/protein carriers. Their injectability and shape memory performance allow them to be applied in bioprinting, minimally invasive surgery, and precision medicine. This review will describe the general materials design, characterization, as well as the current progresses and challenges of these smart polymers.

CROSSLINKING OF SBR COMPOUNDS FOR TIRE TREAD USING BENZOCYCLOBUTENE CHEMISTRY

2019 ◽  
Vol 92 (1) ◽  
pp. 25-42 ◽  
Author(s):  
Akshata Kulkarni ◽  
Coleen Pugh ◽  
Sadhan C. Jana ◽  
Darnell T. Wims ◽  
Ammar Abdel Gawad
Keyword(s):  
Crack Growth ◽  
Abrasion Resistance ◽  
Crack Growth Resistance ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Self Healing ◽  
Styrene Butadiene

ABSTRACT This research investigates the potential of benzocyclobutene (BCB) chemistry for crosslinking styrene-butadiene rubber in conjunction with sulfur curatives with the objective of achieving curing at lower temperatures and/or in shorter times compared with entirely sulfur-based cure formulations. The reversible polysulfidic linkages produced in sulfur crosslinking allow self-healing characteristics but suffer from poor heat-aging stability. The C–C crosslinks from BCB chemistry are irreversible and offer higher resistance to aging, but they do not present apparent self-healing properties. The hybrid curative package based on C–C, C–S, and S–S linkages developed is expected to provide reduced crosslinking time and/or temperature, along with higher crack-growth resistance, the ability to self-heal, higher resistance to fatigue-to-failure, reduced hysteresis, and increased abrasion resistance. The crosslinking performance of 1-substituted BCB-based compounds in conjunction with sulfur is specifically investigated.

scholarly journals Muscle-like fatigue-resistant hydrogels by mechanical training

2019 ◽  
Vol 116 (21) ◽  
pp. 10244-10249 ◽  
Author(s):  
Shaoting Lin ◽  
Ji Liu ◽  
Xinyue Liu ◽  
Xuanhe Zhao
Keyword(s):  
Fatigue Resistance ◽  
Skeletal Muscles ◽  
Amorphous Polymer ◽  
High Strength ◽  
High Water ◽  
Polymer Chains ◽  
High Water Content ◽  
High Fatigue ◽  
Synthetic Hydrogels ◽  
Crack Pinning

Skeletal muscles possess the combinational properties of high fatigue resistance (1,000 J/m2), high strength (1 MPa), low Young’s modulus (100 kPa), and high water content (70 to 80 wt %), which have not been achieved in synthetic hydrogels. The muscle-like properties are highly desirable for hydrogels’ nascent applications in load-bearing artificial tissues and soft devices. Here, we propose a strategy of mechanical training to achieve the aligned nanofibrillar architectures of skeletal muscles in synthetic hydrogels, resulting in the combinational muscle-like properties. These properties are obtained through the training-induced alignment of nanofibrils, without additional chemical modifications or additives. In situ confocal microscopy of the hydrogels’ fracturing processes reveals that the fatigue resistance results from the crack pinning by the aligned nanofibrils, which require much higher energy to fracture than the corresponding amorphous polymer chains. This strategy is particularly applicable for 3D-printed microstructures of hydrogels, in which we can achieve isotropically fatigue-resistant, strong yet compliant properties.

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