scholarly journals Visualization and monitoring of damaging-healing processes of polymers by AIEgen-loaded multifunctional microcapsules

2022 ◽  
Author(s):  
Shusheng Chen ◽  
Ting Han ◽  
Junkai Liu ◽  
Xinting Liang ◽  
Jinglei Yang ◽  
...  
Keyword(s):  
Polymeric Materials ◽  
Dynamic Monitoring ◽  
Collective Effects ◽  
Self Healing ◽  
Polymeric Coatings ◽  
Health States ◽  
Full Field ◽  
Practical Applications ◽  
Fluorescence Color ◽  
Healing Processes

Polymeric materials play an essential and ubiquitous role in modern societies, but they are inevitably damaged during service, which can lead to compromised performance or even direct failure. The sensitive detection and dynamic monitoring of the health states of polymers is thus crucial to increase their reliability, safety, and lifetime. Herein, a facile fluorescence-based approach that can achieve the nondestructive, on-site, real-time, full-field, and sensitive visualization and monitoring of damaging-healing processes of polymers is demonstrated. By embedding novel UV-blocking microcapsules containing a diisocyanate solution of aggregation-induced emission luminogens (AIEgens) into a polymer matrix, the damaged regions of the composite show turn-on fluorescence and dual signal changes in both fluorescence intensity and fluorescence color can be observed during the healing processes. The invisible information of the static health states and dynamic healing processes can be directly and semi-quantitatively visualized by naked eyes based on the collective effects of AIE and twisted intramolecular charge transfer. In addition to the autonomous damage-reporting, self-healing, and health indication functionalities, the microcapsule-embedded polymeric coatings possess excellent photo- and water-protection capabilities, which are appealing to various practical applications.

Self-Healing Polymers and Composites: Extrinsic Routes

2021 ◽  
Vol 18 ◽  
Author(s):  
Nidhi Agrawal ◽  
Bharti Arora
Keyword(s):  
Electronic Devices ◽  
Covalent Bond ◽  
Polymeric Materials ◽  
The Self ◽  
Self Healing ◽  
Polymeric Coatings ◽  
Optical Sensitivity ◽  
Artificial Materials ◽  
Commercial Scale ◽  
End Products

: Polymers have the property to convert the physical stress to covalent bond shuffling thereby acting as the healing agents. Polymeric coatings, paints, electronic devices, drug delivery and many other applications find self-healing materials as a smart technique to prolong the life cycle of the end products. The idea behind these artificial materials is to make it behave like the human body. It should sense the failure and repair before it becomes worse or irreparable. Researchers have explored several polymeric materials which can self-heal through intrinsic or extrinsic mechanisms. This review specifically focusses on extrinsic routes governed by mechanical stress, temperature change in covalent bond, humidity, variation in pH, optical sensitivity and electrochemical effects. Each possible mechanism is further supported by the molecules or bonds which can undergo the transformations under given conditions. On a broader scale, bonds that can self-repair by mechanical force, thermal treatment, chemical modifications, UV irradiation, or electromagnetic phenomenon, are covered under this review. It brings into notice of the shortcomings or challenges in adopting the technology to the commercial scale. The possible molecules or bonds which can undergo the self-healing under certain conditions has been distinctly presented in a well-segregated manner. This review is envisaged to act as a guide for researchers working in this area.

Self Healing of Epoxy Composite for Aircraft's Structural Applications

2008 ◽  
Vol 136 ◽  
pp. 39-44 ◽  
Author(s):  
Willy C.K. Tan ◽  
J.C. Kiew ◽  
K.Y. Siow ◽  
Z.R. Sim ◽  
H.S. Poh ◽  
...  
Keyword(s):  
Composite Structures ◽  
Polymeric Materials ◽  
Hollow Fibre ◽  
The Body ◽  
Strength Increase ◽  
Self Healing ◽  
Structural Applications ◽  
Self Repair ◽  
Repair Systems ◽  
Point Bend

When one cut himself, it's amazing to watch how quickly the body acts to mend the wound. Immediately, the body works to pull the skin around the cut back together. The concept of repair by bleeding of enclosed functional agents serves as the biomimetric inspiration of synthetic self repair systems. Such synthetic self repair systems are based on advancement in polymeric materials; the process of human thrombosis is the inspiration for the application of self healing fibres within the composite materials. Preliminary results based on flexural 3 point bend test on prepared samples have shown the healed hollow fibre laminate has a healed strength increase of 47.6% compared to the damaged baseline laminate. These results gave us confidence that there is a great potential to adopt such self healing mechanism on actual composite parts like in aircraft’s composite structures.

scholarly journals Self-Healing of SiC-Al2O3-B4C Ceramic Composites at Low Temperatures

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 652
Author(s):  
Baoguo Wang ◽  
Rong Tu ◽  
Yinglong Wei ◽  
Haopeng Cai
Keyword(s):  
Flexural Strength ◽  
Low Temperatures ◽  
Ceramic Composite ◽  
Ceramic Composites ◽  
Self Healing ◽  
Vickers Indentation ◽  
Crack Healing ◽  
Practical Applications ◽  
Plasma Sintering ◽  
Spark Plasma

Self-healing ceramics have been researched at high temperatures, but few have been considered at lower temperatures. In this study, SiC-Al2O3-B4C ceramic composite was compacted by spark plasma sintering (SPS). A Vickers indentation was introduced, and the cracks were healed between 600 °C and 800 °C in air. Cracks could be healed completely in air above 700 °C. The ceramic composite had the best healing performance at 700 °C for 30 min, recovering flexural strength of up to 94.2% of the original. Good crack-healing ability would make this composite highly useful as it could heal defects and flaws autonomously in practical applications. The healing mechanism was also proposed to be the result of the oxidation of B4C.

scholarly journals 3D Printing of Solvent-Free Supramolecular Polymers

2021 ◽  
Vol 9 ◽  
Author(s):  
Harald Rupp ◽  
Wolfgang H. Binder
Keyword(s):  
3D Printing ◽  
Dynamic Properties ◽  
Polymeric Materials ◽  
Fundamental Principle ◽  
Supramolecular Polymers ◽  
Fused Deposition Modelling ◽  
Self Healing ◽  
Polymer Science ◽  
Fused Deposition ◽  
Molecular Ordering

Additive manufacturing has significantly changed polymer science and technology by engineering complex material shapes and compositions. With the advent of dynamic properties in polymeric materials as a fundamental principle to achieve, e.g., self-healing properties, the use of supramolecular chemistry as a tool for molecular ordering has become important. By adjusting molecular nanoscopic (supramolecular) bonds in polymers, rheological properties, immanent for 3D printing, can be adjusted, resulting in shape persistence and improved printing. We here review recent progress in the 3D printing of supramolecular polymers, with a focus on fused deposition modelling (FDM) to overcome some of its limitations still being present up to date and open perspectives for their application.

scholarly journals Influence of Network Topology on the Viscoelastic Properties of Dynamically Crosslinked Hydrogels

2020 ◽  
Author(s):  
Emilia M. Grad ◽  
Isabell Tunn ◽  
Dion Voerman ◽  
Alberto S. de Léon ◽  
Roel Hammink ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Stress Relaxation ◽  
Network Topology ◽  
Viscoelastic Properties ◽  
Polymeric Materials ◽  
Direct Result ◽  
Reference Network ◽  
Self Healing ◽  
Combine Stress ◽  
Synthetic Cell

Biological materials combine stress relaxation and self-healing with non-linear stress-strain responses. These characteristic features are a direct result of hierarchical self-assembly, which often results in fiber-like architectures. Even though structural knowledge is rapidly increasing, it has remained a challenge to establish relationships between microscopic and macroscopic structure and function. Here, we focus on understanding how network topology determines the viscoelastic properties, i.e. stress relaxation, of biomimetic hydrogels. We have dynamically crosslinked two different synthetic polymers with one and the same crosslink. The first polymer, a polyisocyanopeptide (PIC), self-assembles into semi-flexible, fiber-like bundles and thus displays stress-stiffening, similar to many biopolymer networks. The second polymer, 4-arm poly(ethylene glycol) (starPEG), serves as a reference network with well-characterized structural and viscoelastic properties. Using one and the same coiled coil crosslink allows us to decouple the effects of crosslink kinetics and network topology on the stress relaxation behavior of the resulting hydrogel networks. We show that the fiber-containing PIC network displays a relaxation time approximately two orders of magnitude slower than the starPEG network. This reveals that crosslink kinetics is not the only determinant for stress relaxation. Instead, we propose that the different network topologies determine the ability of elastically active network chains to relax stress. In the starPEG network, each elastically active chain contains exactly one crosslink. In the absence of entanglements, crosslink dissociation thus relaxes the entire chain. In contrast, each polymer is crosslinked to the fiber bundle in multiple positions in the PIC hydrogel. The dissociation of a single crosslink is thus not sufficient for chain relaxation. This suggests that tuning the number of crosslinks per elastically active chain in combination with crosslink kinetics is a powerful design principle for tuning stress relaxation in polymeric materials. The presence of a higher number of crosslinks per elastically active chain thus yields materials with a slow macroscopic relaxation time but fast dynamics at the microscopic level. Using this principle for the design of synthetic cell culture matrices will yield materials with excellent long-term stability combined with the ability to locally reorganize, thus facilitating cell motility, spreading and growth.

Self-Healing Processes in Concrete

2009 ◽  
pp. 141-182 ◽  
Author(s):  
Erk Schlangen ◽  
Christopher Joseph
Keyword(s):  
Self Healing ◽  
Healing Processes

Self-Healing Functional Polymeric Materials

2015 ◽  
pp. 247-283 ◽  
Author(s):  
Johannes Ahner ◽  
Stefan Bode ◽  
Mathias Micheel ◽  
Benjamin Dietzek ◽  
Martin D. Hager
Keyword(s):  
Polymeric Materials ◽  
Self Healing

Physico-Chemical Characterisation of Protective Coatings and Self Healing Processes

2016 ◽  
pp. 241-298
Author(s):  
Anthony E. Hughes ◽  
Sam Yang ◽  
Berkem Oezkaya ◽  
Ozlem Ozcan ◽  
Guido Grundmeier
Keyword(s):  
Protective Coatings ◽  
Self Healing ◽  
Physico Chemical ◽  
Healing Processes

A room-temperature self-healing elastomer with ultra-high strength and toughness fabricated via optimized hierarchical hydrogen-bonding interactions

2022 ◽  
Author(s):  
Liangliang Xia ◽  
Ming Zhou ◽  
Hongjun Tu ◽  
wen Zeng ◽  
xiaoling Yang ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Mechanical Strength ◽  
Room Temperature ◽  
Polymeric Materials ◽  
High Strength ◽  
Self Healing ◽  
High Mechanical Strength ◽  
Hydrogen Bonding Interactions ◽  
Healing Efficiency ◽  
Good Healing

The preparation of room-temperature self-healing polymeric materials with good healing efficiency and high mechanical strength is challenging. Two processes are essential to realise the room-temperature self-healing of materials: (a) a...

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