Ming Tian

Bio: Ming Tian is an academic researcher from Beijing University of Chemical Technology. The author has contributed to research in topics: Elastomer & Vulcanization. The author has an hindex of 10, co-authored 23 publications receiving 328 citations.

Photothermal-Induced Self-Healable and Reconfigurable Shape Memory Bio-Based Elastomer with Recyclable Ability.

Abstract: Photothermal-induced self-healable and shape memory materials have drawn much attention due to the rapidly growing technical applications and environmental requirements. As epoxy natural rubber (ENR) is a kind of bio-based elastomer with good mechanical properties, weather resistance, and air impermeability, it is of great significance to incorporate ENR with recyclable, photothermal-induced self-healable and shape memory properties. In this study, we report a simple method to cross-link ENR with dodecanedioic acids (DAs) through esterification reaction, and during the cross-linking process, a little aniline trimer (ACAT, a kind of oligoaniline) was added at the same time. Then, the ENR-DA-ACAT vitrimers that were covalently cross-linked with recyclable, self-healable, and multiple responsive properties were obtained, which also possessed various functions. As a result of the transesterification reactions at elevated temperatures, the ENR-based vitrimers possess the ability to be reprocessed and self-heal...

Multifunctional Vitrimer-Like Polydimethylsiloxane (PDMS): Recyclable, Self-Healable, and Water-Driven Malleable Covalent Networks Based on Dynamic Imine Bond

Abstract: Vitrimer is a new class of polymeric materials which can be reprocessed to any shape while being permanently cross-linked. We designed and synthesized a catalyst-free network with poly(dimethylsiloxane)etherimide (PDMS-NH2), terephthalaldehyde (TA), and tri(2-aminoethyl)amine (TREA) through the condensation reaction between amino groups and aldehyde groups. As a result of the exchange reaction of the dynamic imine bond obtained, this PDMS network exhibits the nature of vitrimer-like material, which is examined by solubility and stress-relaxation experiments, and the relaxation time is as short as 64 s at 130 °C. In addition, the vitrimer-like PDMS is malleable and capable of self-healing, and the mechanical properties can be maintained even after three consecutive breaking/mold pressing cycles. Especially, besides heating, this vitrimer-like PDMS can also be recycled and reshaped at ambient temperature due to the exchange reaction of dynamic imine bond when immersed in water, which will potentially lead t...

Adaptable Crosslinks in Polymeric Materials: Resolving the Intersection of Thermoplastics and Thermosets.

Abstract: The classical division of polymeric materials into thermoplastics and thermosets based on covalent network structure often implies that these categories are distinct and irreconcilable. Yet, the past two decades have seen extensive development of materials that bridge this gap through incorporation of dynamic crosslinks, enabling them to behave as both robust networks and moldable plastics. Although their potential utility is significant, the growth of covalent adaptable networks (CANs) has obscured the line between “thermoplastic” and “thermoset” and erected a conceptual barrier to the growing number of new researchers entering this discipline. This Perspective aims to both outline the fundamental theory of CANs and provide a critical assessment of their current status. We emphasize throughout that the unique properties of CANs emerge from the network chemistry, and particularly highlight the role that the crosslink exchange mechanism (i.e., dissociative exchange or associative exchange) plays in the res...

Stretchable Electronics Based on PDMS Substrates.

Abstract: Stretchable electronics, which can retain their functions under stretching, have attracted great interest in recent decades. Elastic substrates, which bear the applied strain and regulate the strain distribution in circuits, are indispensable components in stretchable electronics. Moreover, the self-healing property of the substrate is a premise to endow stretchable electronics with the same characteristics, so the device may recover from failure resulting from large and frequent deformations. Therefore, the properties of the elastic substrate are crucial to the overall performance of stretchable devices. Poly(dimethylsiloxane) (PDMS) is widely used as the substrate material for stretchable electronics, not only because of its advantages, which include stable chemical properties, good thermal stability, transparency, and biological compatibility, but also because of its capability of attaining designer functionalities via surface modification and bulk property tailoring. Herein, the strategies for fabricating stretchable electronics on PDMS substrates are summarized, and the influence of the physical and chemical properties of PDMS, including surface chemical status, physical modulus, geometric structures, and self-healing properties, on the performance of stretchable electronics is discussed. Finally, the challenges and future opportunities of stretchable electronics based on PDMS substrates are considered.

A Microscopic Model for the Reinforcement and the Non Linear Behaviour of Filled Elastomers and Thermoplastic Elastomers (Payne and Mullins Effects)

Abstract: We extend a model regarding the reinforcement of nanofilled elastomers and thermoplastic elastomers. The model is then solved by numerical simulations on mesoscale. This model is based on the presence of glassy layers around the fillers. Strong reinforcement is obtained when glassy layers between fillers overlap. It is particularly strong when the corresponding clusters—fillers + glassy layers—percolate, but it can also be significant even when these clusters do not percolate but are sufficiently large. Under applied strain, the high values of local stress in the glassy bridges reduce their lifetimes. The latter depend on the history, on the temperature, on the distance between fillers, and on the local stress in the material. We show how the dynamics of yield and rebirth of glassy bridges account for the nonlinear Payne and Mullins effects, which are a large drop of the elastic modulus at intermediate deformations and a progressive recovery of the initial modulus when the samples are subsequently put at ...

Nanocomposite hydrogel-based strain and pressure sensors: a review

Abstract: Recently, flexible and wearable electronics have gained considerable research interest due to their potential applications in wearable devices, energy storage materials, electronic skins, sensors, etc. Compared to elastomers, hydrogels demonstrate more potential for flexible electronics because of their biomimetic structures, suitable mechanical properties and excellent biocompatibility. Among all the designs, nanocomposite hydrogel-based strain and pressure sensors which can transmit external stimulus to electrical signals have been intensely investigated due to their high mechanical strength, considerable conductivity and outstanding sensitivity. Numerous reports have been dedicated to the designs, preparations and applications of nanocomposite hydrogels. This review provides an up-to-date and comprehensive summary of research progresses of nanocomposite hydrogel-based strain and pressure sensors including designing strategies, preparing methods and applications of the five nanofiller based hydrogel sensors including carbon nanotube based, graphene oxide based, MXene based, polymer nanofiller based and other nanofiller based sensors. Representative cases are carefully selected and discussed regarding the fabrication, merits and demerits, respectively. Finally, perspectives and challenges are presented for the designs of future nanocomposite hydrogel-based strain and pressure sensors.