Photocurable 3D Printing of High Toughness and Self‐Healing Hydrogels for Customized Wearable Flexible Sensors

The use of flexible sensors has tripled over the last decade due to the increased demand in various fields including health monitoring, food packaging, electronic skins and soft robotics. Flexible sensors have the ability to be bent and stretched during use and can still maintain their electrical and mechanical properties. This gives them an advantage over rigid sensors that lose their sensitivity when subject to bending. Advancements in 3D printing have enabled the development of tailored flexible sensors. Various additive manufacturing methods are being used to develop these sensors including inkjet printing, aerosol jet printing, fused deposition modelling, direct ink writing, selective laser melting and others. Hydrogels have gained much attention in the literature due to their self-healing and shape transforming. Self-healing enables the sensor to recover from damages such as cracks and cuts incurred during use, and this enables the sensor to have a longer operating life and stability. Various polymers are used as substrates on which the sensing material is placed. Polymers including polydimethylsiloxane, Poly(N-isopropylacrylamide) and polyvinyl acetate are extensively used in flexible sensors. The most widely used nanomaterials in flexible sensors are carbon and silver due to their excellent electrical properties. This review gives an overview of various types of flexible sensors (including temperature, pressure and chemical sensors), paying particular attention to the application areas and the corresponding characteristics/properties of interest required for such. Current advances/trends in the field including 3D printing, novel nanomaterials and responsive polymers, and self-healable sensors and wearables will also be discussed in more detail.

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Ultrarobust, tough and highly stretchable self-healing materials based on cartilage-inspired noncovalent assembly nanostructure

Nature Communications ◽

10.1038/s41467-021-21577-7 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Yuyan Wang ◽

Xin Huang ◽

Xinxing Zhang

Keyword(s):

Spider Silk ◽

Self Healing ◽

High Toughness ◽

Healing Efficiency ◽

Strong Interfacial Interaction ◽

Highly Stretchable ◽

Noncovalent Bonds ◽

Actuation Devices ◽

Noncovalent Bonding ◽

Polyurethane Matrix

AbstractSelf-healing materials integrated with excellent mechanical strength and simultaneously high healing efficiency would be of great use in many fields, however their fabrication has been proven extremely challenging. Here, inspired by biological cartilage, we present an ultrarobust self-healing material by incorporating high density noncovalent bonds at the interfaces between the dentritic tannic acid-modified tungsten disulfide nanosheets and polyurethane matrix to collectively produce a strong interfacial interaction. The resultant nanocomposite material with interwoven network shows excellent tensile strength (52.3 MPa), high toughness (282.7 MJ m‒3, which is 1.6 times higher than spider silk and 9.4 times higher than metallic aluminum), high stretchability (1020.8%) and excellent healing efficiency (80–100%), which overturns the previous understanding of traditional noncovalent bonding self-healing materials where high mechanical robustness and healing ability are mutually exclusive. Moreover, the interfacical supramolecular crosslinking structure enables the functional-healing ability of the resultant flexible smart actuation devices. This work opens an avenue toward the development of ultrarobust self-healing materials for various flexible functional devices.

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Extremely Tough and Healable Elastomer Realized via Reducing the Crystallinity of Rigid Domain

Polymer Chemistry ◽

10.1039/d1py00870f ◽

2021 ◽

Author(s):

Chong Xing ◽

Haomin Wu ◽

Ruichun Du ◽

Qiuhong Zhang ◽

Xudong Jia

Keyword(s):

Metal Ions ◽

Self Healing ◽

High Toughness

We propose a new concept of “toughening the rigid” by adding metal ions to sacrifice the crystallinity of the rigid domain, which makes the elastomers with high toughness and self-healing...

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3D Printing of Solvent-Free Supramolecular Polymers

Frontiers in Chemistry ◽

10.3389/fchem.2021.771974 ◽

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.

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On 3D printing of electro-active PVDF-Graphene and Mn-doped ZnO nanoparticle-based composite as a self-healing repair solution for heritage structures

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/09544054211060912 ◽

2021 ◽

pp. 095440542110609

Author(s):

Vinay Kumar ◽

Rupinder Singh ◽

Inderpreet Singh Ahuja

Keyword(s):

3D Printing ◽

Polyvinylidene Fluoride ◽

Nano Particles ◽

Zno Nanoparticle ◽

Self Healing ◽

Fused Deposition ◽

Crack Repair ◽

3D Printed ◽

Doped Zno ◽

Mn Doped

Construction is the part of human activity which is directly linked to urbanization for moving ahead on the path of growth and prosperity. Construction activities in past centuries are now part of our precious heritage. The repair and maintenance of heritage structures are of great importance for present-day researchers. One of the most common damage these century-long constructions faces are in form of surface cracks. In the present study, investigations were performed for a 3D printing-based customized solution for crack repair and maintenance of heritage structures. In this study, polyvinylidene fluoride (PVDF) polymer was reinforced with graphene (Gr) and Mn-doped ZnO nano-particles to prepare a smart composite material for crack repair and restoration. The composite was successfully 3D printed on fused deposition modeling (FDM) based 3D printer after investigating its rheological, thermal, and mechanical properties. The in-house developed composite was tested for smart characteristics to use as a programmable solution for filling cracks. The piezoelectric property and dielectric constant of 3D printed disk-shaped composite (PVDF-Gr-Mn-ZnO) were obtained after DC poling (to be used as stimulus) of the functional prototype. The results of the study suggest that the electro-active nature, volumetric change, and charge storing capacity of the additively manufactured composite may be used practically to acquire the shape of cavity/crack present in the constructed wall and repair the damages that occurred in a heritage site. The photoluminescence (PLS) and atomic force microscopy (AFM) analysis was used to ascertain the properties of the prepared composite. Also, the results obtained from the morphological analysis are reported to support the outcomes of the research.

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A Photoinduced Dual‐Wavelength Approach for 3D Printing and Self‐healing of Thermosetting Materials

Angewandte Chemie ◽

10.1002/ange.202114111 ◽

2021 ◽

Author(s):

Zhiheng Zhang ◽

Nathaniel Corrigan ◽

Cyrille Andre Jean Marie Boyer

Keyword(s):

3D Printing ◽

Dual Wavelength ◽

Self Healing

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3D printing of functional polymers for miniature machines

Multifunctional Materials ◽

10.1088/2399-7532/ac4836 ◽

2022 ◽

Author(s):

Neng Xia ◽

Dongdong Jin ◽

Veronica Iacovacci ◽

Li Zhang

Keyword(s):

3D Printing ◽

Control Strategies ◽

Functional Materials ◽

Functional Polymers ◽

Small Scale ◽

Self Healing ◽

Power Sources ◽

Miniature Robots ◽

Composite Polymers ◽

Printing Techniques

Abstract Miniature robots and actuators with micrometer or millimeter scale size can be driven by diverse power sources, e.g., chemical fuels, light, magnetic, and acoustic fields. These machines have the potential to access complex narrow spaces, execute medical tasks, perform environmental monitoring, and manipulate micro-objects. Recent advancements in 3D printing techniques have demonstrated great benefits in manufacturing small-scale structures such as customized design with programmable physical properties. Combining 3D printing methods, functional polymers, and active control strategies enables these miniature machines with diverse functionalities to broaden their potentials in medical applications. Herein, this review provides an overview of 3D printing techniques applicable for the fabrication of small-scale machines and printable functional materials, including shape-morphing materials, biomaterials, composite polymers, and self-healing polymers. Functions and applications of tiny robots and actuators fabricated by 3D printing and future perspectives toward small-scale intelligent machines are discussed.

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Ultrarobust, tough and highly stretchable self-healing materials based on cartilage-inspired noncovalent assembly nanostructure

10.21203/rs.3.rs-89039/v1 ◽

2020 ◽

Author(s):

Yuyan Wang ◽

Xin Huang ◽

Xinxing Zhang

Keyword(s):

Spider Silk ◽

Interfacial Interaction ◽

Self Healing ◽

Flexible Devices ◽

High Toughness ◽

Healing Efficiency ◽

Strong Interfacial Interaction ◽

Highly Stretchable ◽

Noncovalent Bonds ◽

Noncovalent Bonding

Abstract Self-healing materials integrated with robust mechanical strength and high healing efficiency simultaneously would be of great use in many fields but have been proven to be extremely challenging. Here, inspired by animal cartilage, we present a ultrarobust self-healing material by incorporating high density noncovalent bonds at interface between the assembled interwoven network of two-dimensional nanosheets and polymer matrix to collectively produce a strong interfacial interaction. The resulted nanocomposite material shows robust tensile strength (52.3 MPa), high toughness (282.7 MJ m–3, which is 1.6 times higher than spider silk and 9.4 times higher than metallic aluminum), high stretchability (1020.8%) and excellent healing efficiency (80-100%), which overturns previous understanding of the traditional noncovalent bonding self-healing materials that high mechanical robustness and healing ability tend to be mutually exclusive. Moreover, the interfacical supramolecular crosslinking structure enables the functional-healing ability of the resultant flexible devices. This work opens an avenue toward the development of ultrarobust self-healing materials for various flexible functional devices.

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Highly stretchable, self-healing, and 3D printing prefabricatable hydrophobic association hydrogels with the assistance of electrostatic interaction

Polymer Chemistry ◽

10.1039/d0py00003e ◽

2020 ◽

Vol 11 (29) ◽

pp. 4741-4748

Author(s):

Heng Chen ◽

Beibei Hao ◽

Penghui Ge ◽

Shaojun Chen

Keyword(s):

3D Printing ◽

Electrostatic Interaction ◽

Methacrylic Acid ◽

Butyl Acrylate ◽

Hydrophobic Association ◽

Self Healing ◽

Ethyl Methacrylate ◽

Highly Stretchable ◽

Physically Crosslinked

Self-healing and 3D printing prefabricatable physically crosslinked hydrogels were prepared by copolymerization of butyl acrylate, 2-(dimethylamino)ethyl methacrylate, and methacrylic acid, followed by soaking in water.

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Smart polymers for cell therapy and precision medicine

Journal of Biomedical Science ◽

10.1186/s12929-019-0571-4 ◽

2019 ◽

Vol 26 (1) ◽

Cited By ~ 8

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.

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