scholarly journals Supramolecular Self-Healing Sensor Fiber Composites for Damage Detection in Piezoresistive Electronic Skin for Soft Robots

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2983
Author(s):  
Antonia Georgopoulou ◽  
Anton W. Bosman ◽  
Joost Brancart ◽  
Bram Vanderborght ◽  
Frank Clemens
Keyword(s):  
Healing Process ◽  
Matrix Material ◽  
Fiber Composites ◽  
Self Healing ◽  
Elastomeric Matrix ◽  
Electronic Skin ◽  
Bending Actuator ◽  
3D Printed ◽  
Resilient Response ◽  
Actuator Module

Self-healing materials can prolong the lifetime of structures and products by enabling the repairing of damage. However, detecting the damage and the progress of the healing process remains an important issue. In this study, self-healing, piezoresistive strain sensor fibers (ShSFs) are used for detecting strain deformation and damage in a self-healing elastomeric matrix. The ShSFs were embedded in the self-healing matrix for the development of self-healing sensor fiber composites (ShSFC) with elongation at break values of up to 100%. A quadruple hydrogen-bonded supramolecular elastomer was used as a matrix material. The ShSFCs exhibited a reproducible and monotonic response. The ShSFCs were investigated for use as sensorized electronic skin on 3D-printed soft robotic modules, such as bending actuators. Depending on the bending actuator module, the electronic skin was loaded under either compression (pneumatic-based module) or tension (tendon-based module). In both configurations, the ShSFs could be successfully used as deformation sensors, and in addition, detect the presence of damage based on the sensor signal drift. The sensor under tension showed better recovery of the signal after healing, and smaller signal relaxation. Even with the complete severing of the fiber, the piezoresistive properties returned after the healing, but in that case, thermal heat treatment was required. With their resilient response and self-healing properties, the supramolecular fiber composites can be used for the next generation of soft robotic modules.

scholarly journals A Fully Self-Healing Piezoelectric Nanogenerator for Self-Powered Pressure Sensing Electronic Skin

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Maosen Yang ◽  
Jinmei Liu ◽  
Dong Liu ◽  
Jingyi Jiao ◽  
Nuanyang Cui ◽  
...  
Keyword(s):  
Mechanical Energy ◽  
Healing Process ◽  
Electric Energy ◽  
Piezoelectric Composite ◽  
Human Hand ◽  
Self Healing ◽  
Pressure Sensing ◽  
External Stimulation ◽  
Electronic Skin ◽  
Self Powered

As an important way of converting mechanical energy into electric energy, a piezoelectric nanogenerator (PENG) has been widely applied in energy harvesting as well as self-powered sensors in recent years. However, its robustness and durability are still severely challenged by frequent and inevitable mechanical impacts in real application environments. Herein, a fully self-healing PENG (FS-PENG) as a self-powered pressure sensing electronic skin is reported. The self-healing piezoelectric composite and self-healing Ag NW electrode fabricated through mixing piezoelectric PZT particles and conductive Ag NWs into self-healing polydimethylsiloxane (H-PDMS) are assembled into the sandwich structure FS-PENG. The FS-PENG could not only effectively convert external stimulation into electrical signals with a linear response to the pressure but also retain the excellent self-healing and stable sensing property after multiple cycles of cutting and self-healing process. Moreover, a self-healing pressure sensor array composed of 9 FS-PENGs was attached on the back of the human hand to mimic the human skin, and accurate monitoring of the spatial position distribution and magnitude of the pressure was successfully realized.

scholarly journals Self-Reinforced Nylon 6 Composite for Smart Vibration Damping

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1235
Author(s):  
Bidita Salahuddin ◽  
Rahim Mutlu ◽  
Tajwar A. Baigh ◽  
Mohammed N. Alghamdi ◽  
Shazed Aziz
Keyword(s):  
Matrix Material ◽  
Nylon 6 ◽  
Vibration Damping ◽  
Vibration Energy ◽  
Damping Factor ◽  
Passive Vibration Control ◽  
Reinforced Composite ◽  
Coiled Structure ◽  
The Matrix ◽  
3D Printed

Passive vibration control using polymer composites has been extensively investigated by the engineering community. In this paper, a new kind of vibration dampening polymer composite was developed where oriented nylon 6 fibres were used as the reinforcement, and 3D printed unoriented nylon 6 was used as the matrix material. The shape of the reinforcing fibres was modified to a coiled structure which transformed the fibres into a smart thermoresponsive actuator. This novel self-reinforced composite was of high mechanical robustness and its efficacy was demonstrated as an active dampening system for oscillatory vibration of a heated vibrating system. The blocking force generated within the reinforcing coiled actuator was responsible for dissipating vibration energy and increase the magnitude of the damping factor compared to samples made of non-reinforced nylon 6. Further study shows that the appropriate annealing of coiled actuators provides an enhanced dampening capability to the composite structure. The extent of crystallinity of the reinforcing actuators is found to directly influence the vibration dampening capacity.

scholarly journals Injectable Self-Healing Adhesive pH-Responsive Hydrogels Accelerate Gastric Hemostasis and Wound Healing

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jiahui He ◽  
Zixi Zhang ◽  
Yutong Yang ◽  
Fenggang Ren ◽  
Jipeng Li ◽  
...  
Keyword(s):  
Wound Healing ◽  
Endoscopic Treatment ◽  
Healing Process ◽  
Gelation Time ◽  
Type I ◽  
Self Healing ◽  
Ph Responsive ◽  
Gastric Hemorrhage ◽  
Wound Model ◽  
Arterial Bleeding

AbstractEndoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are well-established therapeutics for gastrointestinal neoplasias, but complications after EMR/ESD, including bleeding and perforation, result in additional treatment morbidity and even threaten the lives of patients. Thus, designing biomaterials to treat gastric bleeding and wound healing after endoscopic treatment is highly desired and remains a challenge. Herein, a series of injectable pH-responsive self-healing adhesive hydrogels based on acryloyl-6-aminocaproic acid (AA) and AA-g-N-hydroxysuccinimide (AA-NHS) were developed, and their great potential as endoscopic sprayable bioadhesive materials to efficiently stop hemorrhage and promote the wound healing process was further demonstrated in a swine gastric hemorrhage/wound model. The hydrogels showed a suitable gelation time, an autonomous and efficient self-healing capacity, hemostatic properties, and good biocompatibility. With the introduction of AA-NHS as a micro-cross-linker, the hydrogels exhibited enhanced adhesive strength. A swine gastric hemorrhage in vivo model demonstrated that the hydrogels showed good hemostatic performance by stopping acute arterial bleeding and preventing delayed bleeding. A gastric wound model indicated that the hydrogels showed excellent treatment effects with significantly enhanced wound healing with type I collagen deposition, α-SMA expression, and blood vessel formation. These injectable self-healing adhesive hydrogels exhibited great potential to treat gastric wounds after endoscopic treatment.

scholarly journals Fabrication of 3D-Printed Interpenetrating Hydrogel Scaffolds for Promoting Chondrogenic Differentiation

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2146
Author(s):  
Jian Guan ◽  
Fu-zhen Yuan ◽  
Zi-mu Mao ◽  
Hai-lin Zhu ◽  
Lin Lin ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Elastic Modulus ◽  
Chondrogenic Differentiation ◽  
Marker Genes ◽  
Self Healing ◽  
Polyethylene Glycol Diacrylate ◽  
3D Microenvironment ◽  
3D Printed

The limited self-healing ability of cartilage necessitates the application of alternative tissue engineering strategies for repairing the damaged tissue and restoring its normal function. Compared to conventional tissue engineering strategies, three-dimensional (3D) printing offers a greater potential for developing tissue-engineered scaffolds. Herein, we prepared a novel photocrosslinked printable cartilage ink comprising of polyethylene glycol diacrylate (PEGDA), gelatin methacryloyl (GelMA), and chondroitin sulfate methacrylate (CSMA). The PEGDA-GelMA-CSMA scaffolds possessed favorable compressive elastic modulus and degradation rate. In vitro experiments showed good adhesion, proliferation, and F-actin and chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the scaffolds. When the CSMA concentration was increased, the compressive elastic modulus, GAG production, and expression of F-actin and cartilage-specific genes (COL2, ACAN, SOX9, PRG4) were significantly improved while the osteogenic marker genes of COL1 and ALP were decreased. The findings of the study indicate that the 3D-printed PEGDA-GelMA-CSMA scaffolds possessed not only adequate mechanical strength but also maintained a suitable 3D microenvironment for differentiation, proliferation, and extracellular matrix production of BMSCs, which suggested this customizable 3D-printed PEGDA-GelMA-CSMA scaffold may have great potential for cartilage repair and regeneration in vivo.

scholarly journals Application of GGBFS and Bentonite to Auto-Healing Cracks of Cement Paste

2018 ◽  
Vol 1 (1) ◽  
pp. 38 ◽  
Author(s):  
J J Ekaputri ◽  
M S Anam ◽  
Y Luan ◽  
C Fujiyama ◽  
N Chijiwa ◽  
...  
Keyword(s):  
Cement Paste ◽  
Surface Crack ◽  
Crack Width ◽  
Healing Process ◽  
Crack Depth ◽  
The Self ◽  
External Loading ◽  
Self Healing ◽  
Carbonation Reaction ◽  
Granulated Blast Furnace Slag

Cracks are caused by many factors. Shrinkage and external loading are the most common reason. It becomes a problem when the ingression of aggressive and harmful substance penetrates to the concrete gap. This problem reduces the durability of the structures. It is well known that self – healing of cracks significantly improves the durability of the concrete structure. This paper presents self-healing cracks of cement paste containing bentonite associated with ground granulated blast furnace slag. The self-healing properties were evaluated with four parameters: crack width on the surface, crack depth, tensile strength recovery, and flexural recovery. In combination with microscopic observation, a healing process over time is also performed. The results show that bentonite improves the healing properties, in terms of surface crack width and crack depth. On the other hand, GGBFS could also improve the healing process, in terms of crack depth, direst tensile recovery, and flexural stiffness recovery. Carbonation reaction is believed as the main mechanism, which contributes the self-healing process as well as the continuous hydration progress.

scholarly journals The importance of oxygen release in diabetic foot ulcer wounds

2019 ◽  
Vol 1 (1) ◽  
pp. 002-011
Keyword(s):  
Diabetic Foot ◽  
Therapeutic Process ◽  
Healing Process ◽  
Foot Ulcer ◽  
Essential Element ◽  
Diabetic Foot Ulcer ◽  
Wound Dressings ◽  
Self Healing ◽  
Healthy Human ◽  
Affected Tissue

Oxygen is the essential element required for proper physiological function of cells, tissues and organs within healthy human body. Thanks to its intricate structure, the skin provides a multiprotective barrier against traumatic and non-traumatic injuries, but also a complex and successful self-healing process of the affected tissue. In the particular case of chronic skin wounds, such as diabetic foot ulcer wounds, there is an immediate demand to develop alternative procedures that prevent infection, speed up healing and eliminate any disrupting factor that may interfere with the therapeutic process. Given the importance of oxygen during wound healing cascade, impressive attention was oriented towards the fabrication of oxygen-releasing wound dressings.

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