Xinzhen Fan

Polymer chemistry and physics

Polymer Science

Polymer material and engineering

In 2023, I enrolled in a part-time program of Data Science offered by WeCloudData, which provided courses in SQL, Python, NumPy, Pandas, and Machine Learning, along with relevant projects over a six-month period.

Designing room-temperature phosphorescent (RTP) hydrogels presents a unique challenge in comparison to RTP polymeric films and powders, due to the quenching of phosphorescence by water molecules within the hydrogel and their inherent softness. This study presents the first example of intrinsic RTP hydrogels without doping by luminophores or stiffening agents. The hydrogel is synthesized by copolymerizing acrylamide (Am) with N-acryloyl-aminoundecanoic acid (NAUA). The hydrophobic NAUA induces phase separation in the hydrogel network and the glass transition of the hydrophobic phase can stiffen the structure and constrain the mobility of water molecules and chain segments. Under such condition, the clustering of amide and carboxylic acid groups triggers the emission of RTP with a persistent afterglow exceeding 1.5 seconds, which is as good as the reported RTP hydrogels with dopants. When the hydrogel is heated above its glass transition temperature, its modulus drops quickly from 20.0 MPa to 0.026 MPa within 2 s and RTP also diminishes. Taking advantage of the temperature-switchable rigidity and RTP behavior, the hydrogels are endowed with functions such as shape memory, temperature-sensing, and information concealment. The results of this project was published in Advanced Optical Materials.

The thermosensitive core-shell structured photonic crystals with upper critical solution temperature (UCST) can be applied as temperature indicators and contribute to a deeper understanding of the mechanism of UCST. Photonic crystals are commonly found in nature, displaying vibrant and colorful appearances. Artificially synthesized nanoparticles, ranging in size from approximately 100 to 600 nanometers, can be arranged in a highly uniform and ordered fashion, enabling the production of photonic crystals for practical use. The core-shell structured photonic crystals have a polymer shell with UCST thermosensitivity. While LCST photonic crystals of this kind have been reported previously, UCST has remained underreported due to its higher sensitivity to external disturbances. In this study, photonic crystals with high size uniformity and excellent optical properties were prepared. Various UCST polymers, both homopolymers and copolymers, were tested as shells, and the study concluded that the molecular weight of the polymer has a significant impact on UCST properties. This research was published as a book chapter.

Previous reports on UCST polymers have focused entirely on hydrogen bonds or ionic interactions within the polymer. This research adds valuable insight into the mechanism of UCST polymers. By synthesizing a monomer with ligand for coordinating Lanthanide ions and copolymerizing it with acrylamide through RAFT polymerization, a water-insoluble polymer was prepared. After adding a coordinating ion, Eu ion, the polymer exhibited UCST behavior with thermoresponsive luminescence, suggesting that ion coordination disrupts the hydrophobic interaction of the ligand and works in conjunction with hydrogen bonding to induce UCST behavior. Simultaneously, red fluorescence from the Eu ion can be generated through the antenna effect. When the temperature drops below the UCST, the polymer aggregates through ionic coordination and hydrogen bonding, causing the Eu ion to emit red fluorescence via the antenna effect. When the temperature rises above the UCST, the hydrogen and coordination bonds break, causing the Eu ion’s fluorescence to disappear, achieving a thermoresponsive fluorescence phenomenon for the applications such as thermo-sensors or themperature indicators. The manuscript for this project is under submission.

Traditional cluster-induced room-temperature phosphorescent polymer materials require water isolation and low temperatures. In contrast, this project developed a polymer hydrogel that triggers phosphorescence upon heating, overcoming the quenching effect of water and the harsh requirement of low temperatures. This hydrogel also possesses shape-memory and self-healing capabilities, along with excellent mechanical properties. It challenges the traditional methods for preparing phosphorescent materials and significantly expands the application range of phosphorescent polymer materials. This work is ongoing.

While both nanosilver and nanocopper have been reported to exhibit good antibacterial properties, each has its limitations. Silver-copper nanocomposites offer a broader-spectrum antibacterial effect. The antibacterial mechanism has been summarized as the generation of reactive oxygen species (ROS), destruction of bacterial cell walls, and the release of silver and copper ions. Silver-copper nanocomposites can be applied to metals such as stainless steel or polymers like polyurethane medical catheters through surface modification, introducing antibacterial properties. This project has been published in the journal Biology.

First author. Published in Advanced Optical Materials (Accepted).

First author. Published in Biology, 2021, 10(2): 137.

First author. Published in World Scientific

Third author. Accepted by Giant 20 (2024): 100342.

Responsible for teaching international chemistry curricula such as A-Level and IB.

Responsible for the research and development of polyurethane and polyester-based textile chemicals and dyeing auxiliaries.

Research Assistant, Department of Chemistry, Université de Montréal, Canada

FRQNT Doctoral Fellowship, Government of Quebec, Canada

Outstanding Youth League Member, Northeast Forestry University

Organizational Committee Member, Party Branch for Polymer Major, Northeast Forestry University

Academic Representative, Polymer Major, Northeast Forestry University

Team Leader, Undergraduate Innovation Experiment on "Polyurethane Wood Coatings," Northeast Forestry University

Third Prize, World Expo Special Competition, Heilongjiang Provincial Academic Competition for University Students

Liangyou Wood Industry Enterprise Scholarship, Zhejiang Province

Recipient of First-Class or Second-Class Scholarship at Northeast Forestry University every semester