Yongjie Wei

Bio: Yongjie Wei is an academic researcher from Jilin University. The author has contributed to research in topics: Simulated body fluid & Ceramic. The author has an hindex of 2, co-authored 6 publications receiving 9 citations.

Fabrication of Sr-functionalized micro/nano-hierarchical structure ceramic coatings on 3D printing titanium

Abstract: Effective and fast osseointegration is significantly affected by the topographic features and chemical compositions of titanium (Ti)-based orthopedic implants. In this study, strontium (Sr) ions fu...

Graphene Oxide-Modified Microcapsule Self-Healing System for 4D Printing

Abstract: Self-healing materials as type of promising smart materials, are gradually applied into electronics, biology, engineering. In this work, we use in-situ polymerization to make melamine-formaldehyde resin (MF) microcapsules to wrap the epoxy resin as repairing agent, and Cu(MI)4Br2 as latent curing agent to cure epoxy resin E-51 from broken melamine-formaldehyde resin (MF) microcapsules. In addition, graphene oxide is used as reinforcing phase through its two-dimensional layered structure to improve the tensile strength to 41.91 MPa, which is higher than the initial materials. The melamine-formaldehyde capsules and latent curing agents are uniformly distributed in the materials according to the digital photos and SEM pictures. It is worth noting that the mechanical strength of the broken materials can be restored to 35.65 MPa after heating at 130 °C for 2 h to repair the damage, and the self-healing efficiency reached up to 85.06%. Furthermore, we also fabricated the 4D printed material with tensile strength of 50.93 MPa through a 3D printer. The obtained materials showed excellent repair effect with the recovery rate up to 87.22%. This work confirms that the designed self-healing system have potential applications in many areas due to their excellent self-healing performance, which provides valuable guidance for designing 4D system.

Anodic TiO2 Nanotubes on 3D-Printed Titanium Meshes for Photocatalytic Applications.

Abstract: In this work, large 3D Ti meshes fabricated by direct ink writing were wirelessly anodized for the first time to prepare highly photocatalytically active TiO2 nanotube (TNT) layers. The use of bipolar electrochemistry enabled the fabrication of TNT layers within the 3D Ti meshes without the establishment of an electrical contact between Ti meshes and the potentiostat, confirming its unique ability and advantage for the synthesis of anodic structures on metallic substrates with a complex geometry. TNT layers with nanotube diameters of up to 110 nm and thicknesses of up to 3.3 μm were formed. The TNT-layer-modified 3D Ti meshes showed a superior performance for the photocatalytic degradation of methylene blue in comparison to TiO2-nanoparticle-decorated and nonanodized Ti meshes (with a thermal oxide layer), resulting in multiple increases in the dye degradation rate. The results presented here open new horizons for the employment of anodized 3D Ti meshes in various flow-through (photo)catalytic reactors.

High Precision 3D Printing for Micro to Nano Scale Biomedical and Electronic Devices

Abstract: Three dimensional printing (3DP), or additive manufacturing, is an exponentially growing process in the fabrication of various technologies with applications in sectors such as electronics, biomedical, pharmaceutical and tissue engineering. Micro and nano scale printing is encouraging the innovation of the aforementioned sectors, due to the ability to control design, material and chemical properties at a highly precise level, which is advantageous in creating a high surface area to volume ratio and altering the overall products’ mechanical and physical properties. In this review, micro/-nano printing technology, mainly related to lithography, inkjet and electrohydrodynamic (EHD) printing and their biomedical and electronic applications will be discussed. The current limitations to micro/-nano printing methods will be examined, covering the difficulty in achieving controlled structures at the miniscule micro and nano scale required for specific applications.

Preparation of robust, self-cleaning and anti-corrosion superhydrophobic Ca-P/chitosan (CS) composite coating on AZ31 magnesium alloy

Abstract: Magnesium (Mg) and its alloys are promising materials in the industrial and biomedical field, but the excessive corrosion rate limits their practical application. To improve the anti-corrosion property of Mg alloys, the composite coating composed of calcium phosphate (CaP) and chitosan (CS) was prepared on AZ31 Mg alloy via simple electrophoretic deposition and chemical conversion method. The water contact angle (WCA) of the composite coating was as high as 158.6° after being modified by stearic acid. Furthermore, a superhydrophobic single CaP coating with the WCA value of 158.5° was fabricated by a chemical conversion method and low energy modification. The superhydrophobic coatings exhibited good self-cleaning properties to prevent the pollution of different pollutants. Furthermore, the obtained superhydrophobic Ca-P/CS composite coating can withstand more times of tape-peeling because of its better bonding ability. Moreover, compared with the superhydrophobic single CaP coating, the composite coating can provide more effective protection to the AZ31 substrate in electrochemical measurements and immersion test. Therefore, the superhydrophobic Ca-P/CS composite coating with significant performance advantages can expand the application fields of Mg alloys.