Key progresses of MOE key laboratory of macromolecular synthesis and functionalization in 2021

In 2021,The MOE Key Laboratory of Macromolecular Synthesis and Functionalization in Zhejiang University had achieved several important results.First,a series of versatile organoboron catalysts were synthesized for ring-opening(co)polymerizations.Second,a catalyst-free polycondensation mechanism was proposed for the production of polyesters with high molecular weights.Third,a co-assembly method that can fabricate films and coatings with controllable structures and properties on various substrates was demonstrated,providing a platform for the construction of novel surface coatings.Forth,facile methods for producing high-productivity poly(propylene carbonate)and semicrystalline polyester have been discovered.And linear non-conjugated polyesters exhibiting yellow-green clusteroluminescence were developed for the first time.Fifth,a supramolecular prodrug nano-assembly strategy has been developed for reactive nitrogen species potentiated chemotherapy.Sixth,a series of tough and stiff supramolecular hydrogels with shape memory properties have been used for information encryption.Seventh,reversible fusion and fission of wet-spun graphene oxide fibers has been successfully achieved.Eighth,three non-conjugated polypeptides were synthesized and the mechanism of clusteroluminescence was studied.Ninth,a series of conducting covalent organic frameworks with high electrical conductivity and carrier mobility have been used as high-performance chemiresistor,electrocatalyst,and organic field-effect transistor.Tenth,the exploration of non-fused electron acceptors,and their photostable mechanism are exemplified for developing high-performance,low-cost and eco-friendly polymer solar cells.Finally,gel-grown long-range ordering bulk-heterojunctions has achieved improved X-ray detector performance.

Poly(vinylidene fluoride)Separators with Dual-asymmetric Structure for High-performance Lithium Ion Batteries

Dual-asymmetric poly（vinylidene fluoride） （PVDF） separators have been fabricated by thermally induced phase separation with dimethyl sulfone （DMSO2） and glycerol as mixed diluents. The separators have a porous bulk with large interconnected pores （-1.0 μm） and two surfaces with small pores （-30 nm）. This dual-asymmetric porous structure endows the separators with higher electrolyte uptake amount and rapider uptake rate, as well as better electrolyte retention ability than the commercialized Celgard 2400. The separators even maintain their dimensional stability up to 160 ℃, at which temperature the surface pores close up, leading to a dramatic decrease of air permeability. The electrolyte filled separators also show high ion conductivity （1.72 mS.cm-1） at room temperature. Lithium iron phosphate （LiFePO4）/lithium （Li） cells using these separators display superior discharge capacity and better rate performance as compared with those from the commercialized ones. The results provide new insight into the design and development of separators for high-performance lithium ion batteries with enhanced safety.

Rapid formation of metal-monophenolic networks on polymer membranes for oil/water separation and dye adsorption

Surface deposition based on metal-phenolic networks(MPNs) has received increasing interest in recent years. The catechol structure is generally considered to be essential to the formation of MPNs. Our most recent results have demonstrated that some kinds of monophenols can form MPNs on substrate surfaces.Herein, we report a fast and effective surface-coating system based on the coordination of 3-(4-hydroxy-3-methoxyphenyl)-2-propenoic acid, a kind of monophenol, with Fe^(3+). Compared with other metal ions such as Cu^(2+)and Ni^(2+), Fe^(3+)with stronger electron acceptability can coordinate with the monophenol more strongly to form MPNs, and moreover, the deposition time significantly decreases to 40 min from generally 24 h. It is demonstrated that the deposition process is controlled by the coordination, Fe^(3+)hydrolysis, and deprotonation of the monophenol. The coatings endow substrates such as polypropylene microfiltration membrane with underwater superoleophobicity, which can be applied in oil/water separation with high separation efficiency and great long-term stability. In addition, the coated membranes are positively charged and thus are useful in selective adsorption of dyes. The present work not only provides a novel, fast, and one-step deposition method to fabricate MPNs, but also demonstrates that the fabrication efficiency of monophenol-based MPNs is comparable with that of polyphenol-based MPNs.

Vertically Oriented Microporous Membranes Prepared by Bidirectional Freezing

Polystyrene membranes with precisely controlled and vertically oriented pores are fabricated by a bidirectional freezing process. In this process, the influence of polymer in growth of diphenyl sulfone （DPS） crystals has been demonstrated by XRD and simulated by DFT based on the interaction between DPS crystal faces and polystyrene （PS）. The influence of temperature gradient on membrane structures is also elucidated. Compared to the original membrane and modified traditional membranes, modified PS membranes with vertically oriented pores show large and stable fluxes in the processes of multiple oil and water separation.