Publications by authors named "Zizheng Fang"

Three-dimensional (3D) printing has emerged as an attractive manufacturing technique because of its exceptional freedom in accessing geometrically complex customizable products. Its potential for mass manufacturing, however, is hampered by its low manufacturing efficiency (print speed) and insufficient product quality (mechanical properties). Recent progresses in ultra-fast 3D printing of photo-polymers have alleviated the issue of manufacturing efficiency, but the mechanical performance of typical printed polymers still falls far behind what is achievable with conventional processing techniques.

View Article and Find Full Text PDF

Alkaline water electrolysis (AWE) plays a crucial role in the realization of a hydrogen economy. The design and development of efficient and stable bifunctional catalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are pivotal to achieving high-efficiency AWE. Herein, WC/MoC nanoparticle-embedded carbon nanofiber (WC/MoC@CNF) with abundant interfaces is successfully designed and synthesized.

View Article and Find Full Text PDF

The combination of three-dimensional (3D) printing and shape memory polymers (SMP) enables programmable shape morphing of complex 3D structures, which is commonly termed four-dimensional (4D) printing. The process requirements of vat photopolymerization-based 3D printing impose limitations on the molecular structure design of SMPs, making it challenging to achieve triple- or multiple-shaped memory effects. Herein, we printed SMPs with different values and obtained an SMP assembly through interfacial welding.

View Article and Find Full Text PDF
Article Synopsis
  • Polyurethane thermosets, commonly used in modern applications, pose significant environmental challenges due to poor recycling methods and low-quality recycled products.
  • A new chemical strategy has been developed to effectively upcycle polyurethane foams, breaking them down into a dissolvable mixture that allows for higher-value end products.
  • This process enables the creation of high-performance, three-dimensional printable resins with customizable mechanical properties, making it a viable and economically attractive solution for recycling these materials.
View Article and Find Full Text PDF

We report herein an efficient method to synthesize 6-membered cyclic monothiocarbonates which are important intermediates for polymonothiocarbonate synthesis the cycloaddition of carbonyl sulfide with 1,3-halohydrin using a low-cost base such as triethylamine and potassium carbonate. This protocol features excellent selectivity and efficiency, mild reaction conditions and easy-to-obtain starting materials.

View Article and Find Full Text PDF

Delicate geometries and suitable mechanical properties are essential for device applications of polymer materials. 3D printing offers unprecedented versatility, but the geometries and mechanical properties are typically fixed after printing. Here, we report a 3D photo-printable dynamic covalent network that can undergo two independently controllable bond exchange reactions, allowing reprogramming the geometry and mechanical properties after printing.

View Article and Find Full Text PDF

Living creatures possess complex geometries, exceptional adaptability, and continuous growing and regenerating characteristics, which are difficult for synthetic materials to imitate simultaneously. A living polymer network with these features is reported. The polymer can be digitally printed into arbitrary 3D shapes and subsequently undergoes growth via living polymerization of a monomer as the nutrient.

View Article and Find Full Text PDF

To realize a wide range of applications using three-dimensional (3D) printing, it is urgent to develop 3D printing resins with different functions. However, the design freedom of the resin formulation is greatly limited to guarantee fast gelation during 3D printing. Herein, we report a reconfigurable polymer network that is compatible with digital light processing (DLP) 3D printing.

View Article and Find Full Text PDF

A recently emerged reversible shape memory effect greatly extends the capability of shape memory polymers and their practical potential. Physical confinement and chemical fixation are individually known to be effective in introducing network anisotropy essential for reversible shape memory. Herein, we demonstrate that synergetic combination of these two mechanisms effectively diversifies the shape-shifting behavior.

View Article and Find Full Text PDF

Peripheral neuromodulation has been widely used throughout clinical practices and basic neuroscience research. However, the mechanical and geometrical mismatches at current electrode-nerve interfaces and complicated surgical implantation often induce irreversible neural damage, such as axonal degradation. Here, compatible with traditional 2D planar processing, we propose a 3D twining electrode by integrating stretchable mesh serpentine wires onto a flexible shape memory substrate, which has permanent shape reconfigurability (from 2D to 3D), distinct elastic modulus controllability (from ~100 MPa to ~300 kPa), and shape memory recoverability at body temperature.

View Article and Find Full Text PDF

The unique capability of topological rearrangement for dynamic covalent polymer networks has enabled various unusual properties (self-healing, solid-state plasticity, and reprocessability) that are not found in conventional thermosets. Achieving these properties in one network in a synergetic fashion can open up new opportunities for shape memory polymer. To accomplish such a goal, the freedom to tune topological rearrangement kinetics is critical.

View Article and Find Full Text PDF

Thermoset shape memory polymer (SMP) with dynamic covalent bonds in the network is a new class of SMPs for which the permanent shape can be reconfigured via topological rearrangement (plasticity). Catalyzed transcarbamoylation has recently been established as an effective exchange reaction for plasticity in cross-linked polyurethane networks. However, ensuring the plasticity severely constrains the network design which adversely affects the ability to tune other classical shape memory properties for practical applications.

View Article and Find Full Text PDF

Thermoset polymers are known for their superior thermomechanical properties, but the chemical crosslinking typically leads to intractability. This is reflected in the great differences between thermoset and thermoplastic shape-memory polymers; the former exhibit a robust shape memory but are not capable of redefining the permanent shape. Contrary to current knowledge, we reveal here that a classical thermoset shape-memory polyurethane is readily capable of permanent reshaping (plasticity) after a topological network rearrangement that is induced by transcarbamoylation.

View Article and Find Full Text PDF