Doctoral student Xunshuang Zhang and co-workers from our team, under the joint supervision of Researcher Liangbin Li and Professor Yanan Ye, focused on key technologies for efficient and selective lithium extraction from salt-lake brines. By integrating directional freeze casting with dopamine-mediated interfacial modification, they developed, for the first time, an LTO@PDA/PVA composite adsorbent featuring directional dendritic through-channels. This design successfully addresses engineering bottlenecks associated with conventional powdered lithium-ion sieves, including particle aggregation, slow masstransfer, difficult recovery, and poor cycling stability, providing a new material strategy and design principle for lithium extraction from complex salt-lake systems. The related research results have been published in Desalination.

In this study, the team uniformly immobilized dopamine-coated lithium metatitanate particles (LTO@PDA) within a PVA matrix and constructed continuous dendritic ion-transport channels through directional freeze casting. The structure–performance–mass transfer relationship was systematically elucidated. Experimental results showed that dopamine modification significantly improved the dispersibility and hydrophilicity of LTO, suppressed particle aggregation, and fully exposed lithium-exchange sites. Meanwhile, the directional dendritic channels greatly shortened ion-diffusion pathways and substantially enhanced mass-transfer efficiency, enabling rapid lithium-ion adsorption. In simulated Qarhan salt-lake brine, the adsorbent exhibited consistent performance advantages: the lithium adsorption capacity reached 25.47 mg·g⁻¹ within 24 h, and the separation factors for Na⁺, K⁺, Ca²⁺, and Mg²⁺ reached up to 822.78, demonstrating excellent anti-interference selectivity.

Despite differences in initial structure and ionic environment, the team identified a common rule: directional dendritic channels can simultaneously improve adsorption kinetics and cycling stability. After 30 consecutive adsorption–desorption cycles, the adsorbent retained no less than 86.7% of its adsorption capacity, while the titanium dissolution rate was as low as 0.3% per cycle. XPS characterization confirmed that Li⁺ adsorption mainly proceeds through Li⁺/H⁺ ion exchange. The dopamine layer assists mass transfer and dispersion through electrostatic interactions but does not participate in the core chemical adsorption process. Based on these key findings, the team proposed an efficient lithium-extraction material design strategy that combines directional dendritic channels with dopamine-mediated interfacial modification. The resulting LTO@PDA/PVA adsorbent integrates high mechanical strength, rapid mass transfer, high selectivity, and long cycling life, making it directly compatible with engineering applications for lithium extraction from salt-lake brines.

This work is the first to introduce a directional dendritic structure into the shaping design of lithium adsorbents. It establishes a quantitative correlation between ion-transport channel structure and lithium-extraction performance, deepens the understanding of the structure–mass transfer–selectivity synergy in polymer composite lithium-ion sieves, and provides key experimental evidence and a technical route for developing engineerable, long-life, and highly selective materials for lithium extraction from salt-lake brines.

This work was supported by the National Natural Science Foundation of China (52303028), the Institutional Platform Project (JZHKYPT-2021-04), and the Innovation Development Fund of the China Innovation Alliance of Uranium Extraction from Seawater (Nos. CNNC-HSTY-2024-003 and CNNC-CXLM-202207).

Xunshuang Zhang, Yiming Hua, Mengyu Xie, et al. Dopamine-coated LTO particles immobilized in PVA with directional dendritic channels for fast and selective lithium capture from salt-lake brines[J].Desalination,2026: 120225.

Doctoral student Kaining He and colleagues in our team, under the joint supervision of Professor Kunpeng Cui and Professor Xueyu Li, systematically investigated the stress relaxation mechanism of dually crosslinked tough polyampholyte hydrogels under multiaxial deformation modes. The related work was published in Macromolecules.

In this work, we systematically examined the stress relaxation behavior of polyampholyte (PA) hydrogels containing both chemical crosslinks and strong ionic-bond physical crosslinks under uniaxial, planar, and equibiaxial deformation modes. Using a biaxial stretching apparatus independently developed in our laboratory, we obtained extensive stress relaxation data under different deformation modes and introduced an accelerated rupture parameter, m, to quantitatively describe the strain-accelerated rupture process of ionic bonds.

The study revealed that the rupture kinetics of ionic bonds exhibit damage anisotropy. During deformation, uniaxial stretching allows greater lateral contraction freedom of polymer chains, which more readily leads to pronounced local stress concentration and thus the fastest ionic bond rupture. In contrast, under equibiaxial stretching, the network is constrained in multiple directions, which relatively alleviates such stress concentration and results in the slowest rupture. This trend was quantitatively described by the accelerated rupture parameter as m _Uniaxial > m _Planar > m _Equibiaxial.

Based on these findings, building upon our previous work on a uniaxial constitutive model, we further developed a transient network constitutive model applicable to multiaxial stretching. In this model, the total stress is decoupled into three contributions: the chemical network, the remaining physical bonds, and the reformed physical bonds. The fitted parameters enable prediction of the nonlinear relaxation process of the gel under complex multiaxial states.

Different from previous studies that were mainly limited to uniaxial testing, this work systematically investigated stress relaxation behavior under multiaxial deformation modes and revealed the dissociation kinetics of strong physical crosslinks from the perspective of “damage anisotropy.” These findings provide new insights for the design of advanced soft materials, such as flexible actuators and artificial cartilage, intended for long-term service under complex loading conditions.

This work was supported by the National Natural Science Foundation of China (52273028 and U2430213).

He,K.; Huang, S.; Zhu, J.; Chu, Z.; Li, Y.; Li, L.; Li, X.; Cui, K.,Multiaxial stress relaxation of dually crosslinked tough polyampholyte gel. Macromolecules 2026, 59(9): 5325-5337.

Recently, our team, under the guidance of Professor Wei Chen, conducted research on the structural design and performance regulation of optical transparent pressure-sensitive adhesives (OCA) for foldable displays. A new strategy was proposed for a dual-layer Janus OCA with a crosslinking density gradient. This work, led by master's student Jiaying Deng and others, addresses issues in traditional OCAs, such as screen creases, interface failure, and uneven stress distribution during repeated folding. By constructing an asymmetric structure with a low crosslinking density layer—high crosslinking density layer along the thickness direction, a balance was achieved between interfacial adhesion and internal cohesion. The research shows that this dual-layer design not only maintains excellent optical performance but also significantly improves the material's mechanical response and folding reliability, providing a new approach for the design of key adhesive layers in next-generation flexible and foldable display devices.

In this study, three types of single-layer OCAs and their corresponding dual-layer structures were systematically developed. The network structure was quantitatively characterized using low-field nuclear magnetic resonance (LF-NMR), double-quantum nuclear magnetic resonance (DQ-NMR), and single-side nuclear magnetic resonance (UNMR). Among them, UNMR, with a spatial resolution of 10 μm, directly verified the crosslinking density gradient along the thickness direction of the dual-layer adhesive film. Performance tests showed that all OCA samples had a transmittance higher than 95% and a haze lower than 0.6% within the visible light range, meeting the requirements for optical transparent adhesives in display applications. Compared to single-layer high-crosslink samples, the dual-layer Janus OCA exhibited better creep recovery ability while maintaining a high peel strength, and it demonstrated superior durability in both static and dynamic folding tests. Notably, when the dual-layer adhesive film M62 was attached to ITO on the low crosslinking density side, it showed the best dynamic folding stability, indicating that this asymmetric gradient structure could more effectively distribute stress, suppress cracks, and prevent interface delamination, thus enhancing the service reliability of foldable display devices.

This research, starting from the polymer network structure, reveals the role of crosslinking density as a key structural parameter in modulating modulus, viscoelastic response, deformation ability, and stress redistribution during the folding process. It also proves the application potential of Janus gradient design in the development of high-performance OCAs. The results provide experimental evidence and theoretical references for the precise design and performance optimization of optical transparent pressure-sensitive adhesives in the field of flexible displays.

This research was supported by the National Natural Science Foundation of China (52422302), the Anhui Provincial Natural Science Foundation (2408055UM001, 2308085UM02, 2208085UM01, 2208085UM04), and the Chinese Academy of Sciences (JZHKYPT-2021-04).

Jiaying Deng, Lei Wu, Xiaojie Chen, Lingxun Qi, Haotian Wu, Jie Chen, Sarah Palloks, and Wei Chen*.Janus optical clear adhesive with tunable crosslinking density gradient for foldable display[J].Polymer, 2026, 351: 129841.

Recently, under the joint supervision of Prof. Liangbin Li and Research Prof. Xueyu Li, doctoral student Wenhao Guo and other team members focused on the application of cellulose-based sustainable optical films in novel display technologies, specifically investigating the homogeneous synthesis and stretching orientation mechanisms of cellulose benzoate films. Through systematic characterization and macroscopic optical property testing, the team revealed the structure-processing-property relationship governed by the competitive orientation between the cellulose main chain and bulky side groups. This provides scientific guidance for the design and manufacturing of high-performance bio-based optical compensation films. The related work was published in the journal ACS Applied Polymer Materials.

In this work, the preparation process and structural characteristics of optical compensation films—a critical core material in novel display technologies such as liquid crystal displays (LCDs) and organic light-emitting diodes (OLEDs)—were explored in depth. As an essential component of wide-color-gamut display panels, optical compensation films currently rely heavily on petroleum-based materials, while conventional bio-based alternatives (such as cellulose triacetate) face the challenge of a restricted birefringence tuning window. To overcome this material limitation, the fundamental scientific issues of cellulose benzoate (CBz) with precise degrees of substitution during processing were investigated in detail to analyze and establish the relationship between macroscopic properties and microscopic structures. This involved utilizing a homogeneous ionic liquid platform to synthesize materials with varying degrees of substitution, followed by uniaxial stretching. The team discovered a non-monotonic V-shaped dependence of birefringence on the degree of substitution, elucidated the steric hindrance-driven side-group orientation inversion mechanism, and successfully achieved precise tailoring of the films' three-dimensional refractive indices (encompassing zero birefringence, anomalous negative-to-zero characteristics, and positive C-plate behavior). This establishes a scientific foundation for the manufacturing of high-performance, eco-friendly optical compensation films.

This research was jointly funded and supported by the Chinese Academy of Sciences Project (JZHKYPY-2021-04) and the LCD Polarizer Compensation Film Project.

Wenhao Guo, Zhouhang Lei, Xingyue Fang, Zhengqi Tan, Xueyu Li^*, and Liangbin Li^*.Benzoate-Substituted Cellulose Films with Tunable Birefringence and Anomalous Optical Anisotropy[J].ACS Applied Polymer Materials, 2026.

Under the joint supervision of Professor Li Liangbin and Associate Researcher An Minfang, our team's doctoral student Guo Wenhao and colleagues focused on molecular structure design. By establishing structure-property relationships, they successfully developed a novel polyamide-imide (PAI) film that combines high optical transparency, excellent thermal stability, and a low coefficient of thermal expansion. This achievement provides an innovative solution to critical material challenges in flexible display technology and is expected to drive the rapid development of fields such as foldable smartphones and wearable electronics. The related work has been published in the journal ACS Applied Polymer Materials.

In this work, a series of diamine monomers containing amide bonds and bulky substituents (such as methyl groups) were designed and copolymerized with 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) via a two-step polycondensation method to prepare novel poly(amide-imide) films. Experimental results demonstrate that the precise introduction of methyl substituents near the imide ring can significantly inhibit the formation of charge transfer complexes (CTC). Simultaneously, it increases the molecular chain spacing and reduces close packing through the steric hindrance effect. The optimized material (3-AMB-TFMB/6FDA) exhibits outstanding performance, featuring excellent optical properties (T_tot=89.0％，YI=0.73), thermal dimensional stability (CTE = 39.6 ppm·K⁻¹), and a high glass transition temperature (T_g=356 ℃). This research resolves the trade-off between optical transparency and thermal stability through molecular design, providing key material support for the development of large-size foldable screens and advanced human-machine interfaces.

This work was supported by the Major Science and Technology Project of Hefei City, Anhui Province under the Open Competition Mechanism (Grant No. 2022-SZD-005), the Hefei Major Special Directed and Commissioned Project Research and Development of Polyvinyl Butyral (PVB) Film for Automotive Safety Glass, the Hefei Natural Science Foundation (Grant No. 202311), and the Chinese Academy of Sciences (Grant No. JZHKYPT-2021-04).

Guo W, Han X, Tan Z, et al. Influence of Bulky Substituents on Optical Transparency and Dimensional Stability of Polyamide-imide[J]. ACS Applied Polymer Materials, 2025.