Novel polyvinyl alcohol/polyacrylic acid hydrogels achieve excellent electromagnetic shielding by the modification of CNTs

Abstract

Carbon nanotubes (CNTs) are widely used as conductive fillers because of their lightweight and easy modification. However, their poor dispersion in solvents limits their otherwise excellent performance. The anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and (3-aminopropyl) triethoxysilane (KH550) were used as modifiers to inhibit the agglomeration of multi-walled CNTs. A high toughness, strong electromagnetic shielding (EMI) hydrogel was prepared by blending polyvinyl alcohol (PVA) and polyacrylic acid (PAA) hydrogel. Addition of a modifier promoted the uniform dispersion of multi-walled CNTs, but also improved the mechanical properties of the hydrogels. An elongation at break (233.9%) and compressive strength (≈2.89 MPa) of PVA/PAA/K-CNTs hydrogel with 0.5 wt% K-CNTs, 8 wt% PVA and 2 wt% PAA were noted. More encouragingly, the total electromagnetic shielding effectiveness was 28.89 dB at just 1-mm thickness. This work provides a general approach for CNT functionalization that may be of great interest to industry.

---

1. Introduction

In the modern era of efficient communication, high-frequency base stations, digital communication, and wireless devices have become ubiquitous in daily life.^1–4 While these devices are essential, they can also generate harmful electromagnetic waves during use.^5–7 Harmful electromagnetic waves can significantly interfere with the function of electronic devices, causing data loss, leakage, critical system failure, and even harm to the human body. Therefore, it is crucial to prevent and solve this problem.^8–12

Currently, shielding materials must be highly flexible, adaptable, and customizable to meet the strict demands of next-generation applications, particularly if miniaturisation is necessary.^13–15 While conventional shielding materials, such as metal foils, provide excellent shielding efficiency, their poor processability severely limits customisation.^16–18

Hydrogel materials exhibit remarkable shape adaptability and self-healing ability, making them superior to dry materials. They ensure stable and long-lasting interfaces with protected materials, and have promising applications in various fields, such as wearable electronic devices, aerospace, “electronic skins”, human motion monitors, and energy storage materials.^19–23

Reports have shown that conventional polyvinyl alcohol (PVA)/polyacrylic acid (PAA) hydrogels do not provide electromagnetic shielding (EMI). Therefore, the key to preparing hydrogel-type electromagnetic shielding materials is to use appropriate preparation methods and select effective functional fillers that do not damage the three-dimensional network structure or alter the internal water environment. This approach can achieve the desired electromagnetic shielding performance.^24,25

Carbon nanotubes (CNTs) are structures composed of graphite and carbon. They consist of one or more concentric tubes with a hexagonal honeycomb lattice spirally wound.^26–28 In practical applications, lightweight and easy-to-modify CNT materials are often preferred.^29–31 It is important to note that the physical properties of CNTs can cause them to aggregate, which can negatively impact their performance. However, this issue can be resolved through modification, resulting in the even dispersion of CNTs. Lei et al.³² prepared AU@CNTSA PDMS flexible hydrogels by permeating polydimethylsiloxane (PDMS) into a gold (AU)@cntsa (SA) spongy skeleton. Among them, gold nanoparticles coated on the surface of CNTs can effectively improve the electrical conductivity and electromagnetic shielding properties of the composites. In addition to using metal element modification, Guan et al.³³ used cellulose nanofibers (CNFs) and CNTs to construct an interpenetrating bionic hydrogel consisting of carbon nanotube network and cellulose nanofiber network. The network formed by CNTs provides good conductivity, but its weak interaction and lack of high mechanical strength is made up by the network formed by CNFs. Yang et al.³⁴ similarly used CNFs as dispersants to incorporate multi-walled CNTs into hydrophobic associative polyacrylamide (PAM) hydrogels. A type of strong, mechanical and self-healing hydrogel with certain electromagnetic shielding properties was prepared.

Even though CNT hydrogels have shown great potential in electromagnetic shielding, the construction of their conductive networks and the study of CNT modification remain to be further explored. PVA nanotubes, PAA, and multi-walled CNTs were used to form a double-network structure. Two different modifiers were employed to modify the CNTs. The effects of different modification methods on the structure and properties of the hydrogel composites were investigated, providing help for CNT modification.

2. Experimental

2.1. Materials

PVA-124 (AR, degree of polymerization = 2400) was purchased from Xilong Science. PAA (50% aqueous solution, MW: 3000) was obtained from Shanghai Aladdin. CNTs were procured from Suzhou Tanfeng Graphene Technology. (3-Aminopropyl) triethoxysilane (KH550; 98%) was purchased from Macklin. Sodium dodecyl benzene sulfonate (SDBS; 90.3%) was from Pedder Pharmaceuticals.

2.2. Modification of CNTs

At room temperature, the surface activator SDBS (1.5 mL, 3 mL, 4.5 mL) was sequentially added to beakers containing CNTs (0.5 g, 1 g, 1.5 g), respectively. Each mixture was stirred magnetically for 0.5 h, followed by ultrasonication for 0.5 h to obtain stable modified CNT dispersions. The same method was employed to prepare KH550-modified CNTs.

2.3. Preparation of modified PVA/PAA/CNTs hydrogel

The modified PVA/PAA/CNTs hydrogel was prepared using a one-bath hydrothermal method. The modified CNTs solution was added to PVA (8 wt%) and PAA (2 wt%) and placed in a water bath at 95 ± 2 °C. To ensure complete dissolution of PVA crystals, a rod was used and stirred at intervals of several minutes. Finally, the modified PVA/PAA/CNTs hydrogel was prepared using the cyclic freeze–thaw method for three cycles (−5 to −10 °C for 20 h and thawing at room temperature for 4 h).

2.4. Characterization

Scanning electron microscopy (SEM) was used to observe the morphology of hydrogels. The morphology of each hydrogel was observed using a scanning electron microscope (Quanta FEG 250; FEI). The hydrogel was first pre-frozen at −20 °C for 12 h, then transferred to a −90 °C environment for freeze-drying for 48 h. After freeze-drying, the hydrogel sample was quenched in liquid nitrogen. A cross-section of the cryo-fractured hydrogel was selected and mounted on an SEM stage using conductive adhesive for subsequent morphological observation. Fourier transform infrared spectra were recorded using a Nicolet iS50 spectrometer (Thermo Fisher Scientific) in the wavenumber range 500 to 4000 cm⁻¹via an attenuated total reflection (ATR) method. The test involved three cumulative scans with a resolution set at 4 cm⁻¹. XRD (Rigaku Ultima IV) was performed using a copper target. The test employed Cu-Kα radiation as the source, with a measurement angle range of 10–80°, a scanning rate of 10° min⁻¹, voltage of 30 kV, and current of 50 mA. The water content (Φ) can be obtained by a simple measurement using eqn (1):³⁵where W_a is the weight of the raw sample, and W_e is the weight of the final dried sample after drying for 24 h at 70 °C in a vac-drying room. It should be noted that the samples after the moisture content test were tested directly for swelling properties.³⁶

Testing of the thermal properties of the hydrogel was carried out using a differential scanning calorimeter (DSC 25). The rate of temperature change was 10° min⁻¹. Thermogravimetric analysis (TGA) was conducted using a TGA55 instrument from TA Instruments under a nitrogen atmosphere at a flow rate of 60 mL min⁻¹. The sample was heated at a rate of 10 °C min⁻¹ from room temperature to 600 °C. Tests of mechanical properties (tensile and compressive) were carried out uniformly with a universally available mechanical testing rig (CMT 6104; Systems (China) Company) at 15 °C and relative humidity of 45–50%. The mechanical testing standards of hydrogel samples were unified in accordance with the national standard (GB/T 1040.3-2006). The size of the sample was dumbbell-shaped (tensile) or cylindrical (compression). The four-probe tester (RK-YA) is a commonly used device for conductivity measurements, and is commissioned at 5 V with a spacing of 2.35 mm between each stylus, according to national standards. Samples were first cut into rectangular strips 10-mm long, 3.5-mm wide, and 1-mm thick, and then tested at room temperature, at least three times for each sample. The EMI test instrument used was a vector network analyzer (N5225B; Keysight), the test-sample dimensions were a length of 10 mm, width of 3.5 mm, and thickness of 1 mm. Samples in the X-band (8.2–12.4 GHz) were tested, analyzed and calculated.

3. Results and discussion

3.1. Morphology of PVA/PAA/CNTs hydrogels

Fig. 1a shows the technical route. For the hydrogel without the addition of CNTs (Fig. 1b), close observation revealed that the distribution of pores was uneven and the pore size was relatively large, showing a loose internal structure. After the addition of modified CNTs, the pore distribution became more uniform and the pore size tended to decrease (Fig. 1c and d). SEM of the hydrogels showed that the addition of CNTs had a positive effect on narrowing the pore distribution and reducing the pore size.³⁷ Obviously, the addition of CNTs resulted in a smaller pore size and narrower distribution of pore size and, thus, a more compact and dense porous structure.³⁸

Fig. 1 (a) Technical route (schematic). (b) SEM images of PVA/PAA hydrogels. (c) SEM images of PVA/PAA/S-CNTs hydrogels. (d) SEM images of PVA/PAA/K-CNTs hydrogels.

Infrared spectroscopy was used to compare PVA/PAA hydrogels and their individual compounds (Fig. 2a). The PVA structure contains C–H, O–H, and C=O, resulting in intermolecular and intramolecular hydrogen bonds within the hydrogel. Upon the introduction of K-CNTs into the hydrogel, the O–H stretching peak shifted from 3381.45 to 3309.89 cm⁻¹, indicating a hydrogen bond between K-CNTs and PVA/PAA.²⁰ A new absorption peak was observed at 1561.094 cm⁻¹, which corresponded to the stretching vibration absorption peak of C–H. Additionally, new absorption peaks were observed at 1411.58 cm⁻¹ and 1089.584 cm⁻¹, corresponding to the stretching vibration absorption peaks of C–O–Si and Si–C.³⁹ These observations suggested that the CNTs were salinized. The modified CNTs were coated with SDBS, as confirmed by the appearance of a new infrared absorption peak at 1552.433 cm⁻¹34. This peak was attributed to the S–O bond vibration of the benzene sulfonic group in SDBS, while the absorption peak at 1411.156 cm⁻¹ was due to the stretching vibration of the C=C bond on the benzene ring in SDBS. Due to dispersion and interaction, combining CNTs and PVA can be challenging. However, modifying multi-walled CNTs can resolve these issues.

Fig. 2 (a) FTIR spectra of PVA/PAA/0-CNTs hydrogel, PVA/PAA/K-1.5-CNTs hydrogel, and PVA/PAA/S-1.5-CNTs hydrogel. (b) XPS spectra of PVA/PAA/0-CNTs hydrogel, PVA/PAA/K-0.5-CNTs hydrogel, and PVA/PAA/S-0.5-CNTs hydrogel. (c) Melting curves of PVA/PAA/K-CNTs hydrogel. (d) Melting curves of PVA/PAA/S-CNTs hydrogel. (e) TG curves of PVA/PAA/K-CNTs hydrogel. (f) TG curves of PVA/PAA/S-CNTs hydrogel.

XRD peaks provided the key data to confirm the physical crosslinking of crystalline microregions (Fig. 2b). CNTs have little effect on the crystallinity of PVA, which is due to the Johannes Diderik van der Waals force interaction between PVA/PAA/CNTs. The peak of PVA/PAA/CNTs hydrogels was ∼19.47°, which indicated that modification of the silane coupling agent did not destroy the basic structure of CNTs. The peaks at 40.91° and 40.58° clearly identified the characteristic peaks of PVA/PAA/CNTs hydrogel crystals,⁴⁰ and the strength increased with the addition of CNTs. It is worth mentioning that the peak was sharper than the XRD curve of 0-CNTs. These data indicated that the PVA microcrystals formed during freezing–thawing had a wide particle size distribution.⁴⁰ The thermal stability of hydrogels containing K-CNTs was improved. The degradation temperature and residue of PVA/PAA/S-CNTs hydrogels increased in the presence of SDBS. Addition of SDBS-modified S-CNTs to PVA/PAA hydrogels improved the dispersion of CNTs in the polymer matrix and increased their interaction. It is possible that the surfactant gradually decomposed and moved to higher temperatures. As the decomposition temperature increased, the amount of SCNTs incorporated and residual PVA/PAA/S-CNTs hydrogels also increased.⁴¹

The thermal properties of various PVA/PAA/CNTs hydrogels were analysed using DSC, as shown in Fig. 2c and d. The crystallisation peak of PVA/PAA/CNTs hydrogels shifted from 224 °C to around 230 °C, and a peak was not observed in the cooling and second heating curves. The melting curves showed that incorporating CNTs altered by different modifiers increased the melting point of PVA/PAA/CNTs hydrogels. Additionally, the presence of CNTs increased the physical bonding point of the PVA molecular chains and decreased the flexibility of the molecular chains, thereby preventing the crystallisation of PVA during cooling. It has been demonstrated that the presence of modified CNTs is responsible for these effects. Hydrogels were significantly improved with the presence of modified CNTs, as shown by melting curves.⁴²

Hydrogels are hydrophilic polymer chains that can absorb large amounts of water. The analytical properties of water contained in hydrogels are used for thermal analysis in theory. The loss of water content observed in TGA is referred to as the loss of water molecules in the hydrophilic region (see Tables S1 and S2). As demonstrated in Fig. 2e and f, the maximum decomposition temperature of the hydrogel increased from 296.7 °C before modification to approximately 310 °C after modification. These data indicate that the modified silane layer had remarkable thermal stability to the PVA/PAA hydrogel. At 600 °C, the carbon residue rate of the PVA/PAA/K-CNTs hydrogel increased significantly with an increase in the K-CNTs ratio, from 7.32% to 27.24%. Therefore, the thermal stability of PVA/PAA/K-CNTs with K-CNTs was better. Additionally, the degradation temperature and residual amount of PVA/PAA/S-CNTs hydrogels increased in the presence of SDBS. Similar to PVA/PAA/K-CNTs hydrogels, the addition of SDBS-modified S-CNTs to PVA/PAA hydrogels improved the dispersion of CNTs in the polymer matrix and increased their interaction. It is possible for the surfactant to gradually break down and move to higher temperatures. This, in turn, increases the residue of PVA/PAA/S-CNTs hydrogels as the degradation temperature moves to higher temperatures.

3.2. Characterization of the PVA/PAA/CNTs hydrogel

The electrical properties of each hydrogel were assessed by connecting it to an LED lamp in a circuit (Fig. 3a–c). The LED lamp was used to demonstrate the conductivity of the sample. The improved dispersion of CNTs allowed electrons to move more freely, resulting in a brighter LED light. Furthermore, crosslinking became denser after modification, allowing for even greater conductivity (Fig. 3e and h). The modified conductivity of KH550 was 170 S mm⁻¹, while that of SDBS was 1650 S mm⁻¹.

Fig. 3 (a)–(c) Conductivity photographs of PVA/PAA/CNTs hydrogels. (d) Water content change of the PVA/PAA/CNTs hydrogel. (e) Conductivity and resistivity of PVA/PAA/K-CNTs hydrogels. (f) and (g) Water content and swelling rate of PVA/PAA/K-CNTs hydrogels. (h) Conductivity and resistivity of PVA/PAA/S-CNTs hydrogels. (i) and (j) Water content and swelling rate of PVA/PAA/S-CNTs hydrogels.

Upon the addition of K-CNTs and S-CNTs, the swelling rate of the hydrogel was reduced significantly (Fig. 3g and j). In Fig. 3f, the water content of hydrogels with higher K-CNT content consistently falls below that of PVA/PAA hydrogels. This occurs because K-CNTs form physical crosslinks within the hydrogel matrix. Higher CNT content increases the solid content and network density within the hydrogel, facilitating the formation of capillary pores. However, CNTs are hydrophobic materials, making it difficult for water molecules to enter their capillary pores or penetrate the network within these pores. This phenomenon reduces the space available for water molecules within the composite gel, leading to a slight decrease in its water content. Similarly, S-CNTs are linked to PVA/PAA molecules through crosslinking points within the hydrogel to form a network structure. After reaching a certain swelling rate, the tension required to separate the fiber network from each other gradually increases due to the restriction of the crosslinking points, and the swelling rate slows down when the contraction tension of the fibers and the tension exerted by the water molecules on the fiber network are the same.⁴³ When the contraction stress and expansion stress exerted by the water molecules are equal, the expansion reaches equilibrium (Fig. 3i).

As demonstrated in Fig. 4a–d, the modified hydrogel sample had good resilience and deformation recovery, retaining its original appearance. To further investigate the mechanical properties of the hydrogels, tensile and compression tests were performed. As expected, the PVA/PAA/K-0-CNTs hydrogel showed the lowest tensile strength of 1.18 MPa and elongation at break of 163.1%. With an increase in K-CNTs content, the tensile strength of PVA/PAA/K-CNTs composite hydrogels first increased and then decreased, but both were higher than that of PVA/PAA gels (Fig. 4e and f). The tensile strength and elongation at break of composite gels reached the maximum at the content of K-0.5-CNTs, and were 1.64 MPa and 282.9%, respectively. Taken together with the cross-sectional morphology of the composite hydrogel, the PVA/PAA/K-0.5-CNTs composite hydrogel had the smallest and uniformly distributed pore size, and the three-dimensional mesh structure deformed uniformly during stretching. Hence, the tensile strength of the composite hydrogel with this component was the largest. However, the addition of excess CNTs would destroy hydrophobic interactions and the network internal structure. For example, the composite hydrogels with K-0.5-CNTs and K-1-CNTs components had a non-uniform pore size distribution and pore entanglement, which would lead to the concentration of stress during tensile stretching, and thus the tensile strength will be reduced, resulting in weakened mechanical properties.⁷ It is worth noting that when the CNTs loading was >1.5 wt%, it became difficult to introduce K-CNTs into PVA/PAA solution and prepare composite hydrogels. The reason is that the high mass ratio of multi-walled CNTs hampers uniform dispersion in the matrix solution.⁵ Similar to the tensile strength test described above, the curve of compressive strength against CNTs content had a peak due to the agglomeration of CNTs at high content (Fig. 4g).

Fig. 4 (a)–(d) Toughness characterization photographs (a) raw. (b) Curved. (c) Multi-segment twist. (d) Rehabilitated. (e) and (f) Stress–strain curve. The strength and elongation at break (stretch) of PVA/PAA/K-CNTs hydrogels (stretch). (g) Stress–strain curve of PVA/PAA/K-CNTs hydrogels (compression). (h) and (i) Stress–strain curve. The strength and elongation at break (stretch) of PVA/PAA/S-CNTs hydrogels (stretch). (j) Stress–strain curve of PVA/PAA/S-CNTs hydrogels (compression).

Similar to PVA/PAA/K-CNTs hydrogels, pure PVA/PAA/S-0-CNTs hydrogels exhibited very low tensile strength and good ductility (elongation at break ≈181%). However, the best tensile properties of the samples were obtained when the content of S-CNTs reached 1.5% wt%. The tensile strength and elongation at break of S-1.5-CNTs specimens were increased by 218% and 11.04%, respectively, when compared with S-0-CNTs (Fig. 4h and i). An increase in mechanical properties was proportional to S-CNTs loading. The mechanical properties of hydrogels increased with an increase in S-CNTs loading. This could have occurred because after chemically modifying CNTs with S -CNTs, the organic groups on the surface of the CNTs promoted the compatibility of the CNTs with PVA/PAA, which led to a more homogeneous distribution of the CNTs in the composites, and further enhanced the reinforcing effect of the CNTs.²⁸ The addition of S-CNTs to hydrogels is another effective method to modify the mechanical properties. To date, most commercial polymers have been employed as matrix materials to investigate the reinforcing effects of CNTs. Research has indicated that CNTs exhibit excellent reinforcing properties. Achieving effective load transfer to CNTs requires good dispersion and interfacial bonding strength. This upward trend becomes more pronounced if strain >50%. In the present study, the maximum compressive strain was fixed at 70% to ensure that the hydrogel did not rupture during testing. CNT-reinforced hydrogels exhibited outstanding compressive resistance. With further increases in CNT content, fracture stress improved significantly. The PVA/PAA/S-CNTs composite hydrogel displayed exceptional strength and toughness, confirming the significant reinforcing effect of CNTs upon hydrogels (Fig. 4j).

Based on the analysis of the electrical properties of prepared hydrogels, their EMI shielding properties were also characterized. The EMI SE of the PVA/PAA/K-CNTs hydrogel reached about 11, 29, 19, and 17 dB at a thickness of 1 mm (Fig. 5a–c). These data suggested that the CNTs in the hydrogel were uniformly distributed in the network formed by the PVA/PAA, forming a homogeneous three-dimensional network. CNTs overlap each other to form many nodes, so they are highly conductive, which leads to impedance mismatch and a large amount of reflection of electromagnetic waves. In addition, most of the electromagnetic waves entering the material are absorbed due to multiple reflections from the many interfaces formed between the K-CNTs and PVA/PAA. It is worth our attention that the PVA/PAA hydrogels exhibited limited EMI shielding performance (≈11 dB) due to relatively low conductivity. After the introduction of S-CNTs into the PVA/PAA matrix, the EMI shielding performance was greatly improved. For the composite hydrogel containing 0.5 wt% S-CNTs, the EMI SE was increased from 11 to 23 dB, and a gradual increase in EMI SE could be obtained by increasing the content of S-CNTs. Moreover, the best EMI shielding performance (≈30 dB) was obtained when the content of S-CNTs was 1.5 wt%, which was about three-times that of PVA/PAA (Fig. 5d and e).

Fig. 5 (a) Electromagnetic shielding effectiveness of PVA/PAA/K-CNTs hydrogels. (b) T–R–A coefficient of PVA/PAA/K-CNTs hydrogels. (c) Average EMI SET, SEA, and SER of PVA/PAA/K-CNTs hydrogels. (d) Electromagnetic shielding effectiveness of PVA/PAA/S-CNTs hydrogels. (e) T–R–A coefficient of PVA/PAA/S-CNTs hydrogels. (f) Average EMI SET, SEA, and SER of PVA/PAA/S-CNTs hydrogels.

To explain the EMI shielding performance theoretically, SER, SEA and SET are shown in detail in Fig. 5f. For SER, there was a small increase with an increase in the S-CNTs concentration. The reason is that the number of mobile charge carriers gas a decisive role in the SER, and a rising S-CNTs content will provide more mobile charge carriers to interact with the incoming microwaves. Then, as the S-CNTs content increases, the SEA increases dramatically because the gradual increase in the concentration of S-CNTs leads to higher complex permittivity and more conductive networks to act as dissipative mobile charge carriers.⁴⁴

Absorption and reflection had important roles in the microwave shielding of these hydrogels. This was due to the porous structure, the presence of a conductive network of S-CNTs in the pore walls and the ions in the water within the pores leading to repeated absorption and reflection of incident microwaves. The incoming microwaves are trapped by the porous structure of the hydrogel. As a result, most of the incoming microwaves are absorbed and dissipated, while a very small fraction can pass through the hydrogel. In addition, the increase in the content of S-CNTs increases the conductivity of these hydrogels, but also decreases the pore size, which leads to higher pore density. In addition, the increase in pore density will increase the pore–substrate interface. The increasing pore–substrate interface and conductivity will lead to more incident microwaves being reflected,⁴⁵ multiply reflected and absorbed, thus trapping more microwaves in the porous structure and attenuating them efficiently for optimization of EMI shielding performance.

4. Conclusions

We have presented a simple method for preparing PVA/PAA/CNTs hydrogels with mechanical strength and electromagnetic shielding properties. The hydrogels also exhibited high tensile and compressive strength. These properties were achieved through the modification of CNTs and the addition of a PVA/PAA one-bath hydrothermal method and cyclic freezing. Chemical crosslinking between modified CNTs and PVA/PAA could improve the mechanical properties of PVA/PAA/CNTs hydrogels. The properties of hydrogels were dependent upon their modifiers. Due to the electrostatic and steric hindrance of the surfactant polyvinyl alcohol and the synergistic effect of the mixture, the mechanical strength of the SDBS-modified PVA/PAA/S-1.5-CNTs hydrogel was increased to 1.05 MPa, and the elongation at break was 201.65%. Similarly, the hydrogel modified by KH550 had a high electromagnetic shielding effectiveness of 28.98 dB. The physical parameters (deformation ability, enthalpy) of PVA/PAA/CNTs hydrogels also changed. This work provides a simple method to prepare an extensible polyvinyl alcohol nanotube polymer hydrogel for electromagnetic shielding.

Conflicts of interest

No potential conflict of interest is reported by the authors.

Data availability

Authors will supply the relevant data in response to reasonable requests.

Supplementary information (SI) is available. See DOI: https://doi.org/10.1039/d5nj02240a.

Acknowledgements

This work was supported by National Natural Science Foundation of China Project (52163001), Guizhou Provincial Science and Technology Program Project Grant (Qiankehe Platform Talents-CXTD [2021]005, Qiankehe Platform Talents-GCC [2022]010-1, Qiankehe Platform Talents-GCC[2023]035, Qiankehe Platform Talents-CXTD[2023]003), Guizhou Minzu University Research Platform Grant (GZMUGCZX [2021]01), Central Guided Local Science and Technology Development Funds Project (Qiankehe Zhong Yindi [2023]035), Green Chemistry and Resource Environment Innovation Team of Guizhou Higher Education Institutions (Guizhou Education and Technology [2022] No. 13), Doctor Startup Fund of Guizhou Minzu University (GZMUZK [2024] QD77), Guizhou Province Special Fund for innovative capacity building of scientific research institutions (Qiankehe Fuqi [2023]001, Qiankehe Fuqi [2024]002-1), Guizhou Provincial Science and Technology Program Project (Qiankehe Platform KXJZ[2024]022), and Centralized Guided Local Science and Technology Development Funds Project (Qianke Hezhong Cidi (2025)013).

References

1. Y. Xu, M. Pei, J. Du, R. Yang, Y. Pan, D. Zhang and S. Qin, New J. Chem., 2023, 47, 13721–13728.
2. Y. Xu, M. Pei, X. Zhan, H. Wang, D. Zhang and S. Qin, New J. Chem., 2023, 47, 21475–21484.
3. X. Ding, Y. Wang, R. Xu, Q. Qi, W. Wang and D. Yu, Cellulose, 2019, 26, 8209–8223.
4. S. Tan, S. Guo, Y. Wu, T. Zhang, J. Tang and G. Ji, Adv. Funct. Mater., 2024, 35, 2415921.
5. S. Roy and J.-W. Rhim, Materials, 2020, 13, 4369–4383.
6. Z. Barani, F. Kargar, Y. Ghafouri, S. Ghosh, K. Godziszewski, S. Baraghani, Y. Yashchyshyn, G. Cywiński, S. Rumyantsev, T. T. Salguero and A. A. Balandin, Adv. Mater., 2021, 33, e2007286.
7. B. Lin, C. Li, F. Chen and C. Liu, Polymers, 2021, 13, 3813–3826.
8. Y. Xu, Y. Tan, Y. Xue, M. Pei, D. Zhang, S. Liu and S. Qin, Polym. Eng. Sci., 2023, 63, 3555–3564.
9. W. Zhang, L. Wei, Z. Ma, Q. Fan and J. Ma, Carbon, 2021, 177, 412–426.
10. T. Zhou, X. Zhan, K. Diao, J. Du, Y. Xu, J. Du, R. Yang, S. Qin and D. Zhang, Prog. Org. Coat., 2024, 196, 108750.
11. C. Yu, S. Zhu, C. Xing, X. Pan, X. Zuo, J. Liu, M. Chen, L. Liu, G. Tao and Q. Li, J. Alloys Compd., 2020, 820, 153108.
12. M. Fang, L. Huang, Z. Cui, P. Yi, H. Zou, X. Li, G. Deng, C. Chen, Z. Geng, J. He, X. Sun, J. Shui, R. Yu and X. Liu, Adv. Funct. Mater., 2024, 35, 2418870.
13. S. Zhao, G. Siqueira, S. Drdova, D. Norris, C. Ubert, A. Bonnin, S. Galmarini, M. Ganobjak, Z. Pan, S. Brunner, G. Nyström, J. Wang, M. M. Koebel and W. J. Malfait, Nature, 2020, 584, 387–392.
14. T. Zhou, Y. Tan, R. Yang, Y. Xu, X. Zhan, J. Du, K. Diao, S. Qin and D. Zhang, Polym. Compos., 2024, 46, 3264–3277.
15. X. Huang, Y. Zhang, X. Zhang, T. Xu, X. Guan, Y. Wu, S. Tan, H. Zhang and G. Ji, Compos. Commun., 2025, 54, 102292.
16. R. K. Manoharan, S. Mohandoss, F. Ishaque and Y.-H. Ahn, Acs Appl. Polym. Mater., 2023, 5, 4019–4033.
17. Y. Xia, W. Gao and C. Gao, Adv. Funct. Mater., 2022, 32, 2204591.
18. J. Liu, M.-Y. Yu, Z.-Z. Yu and V. Nicolosi, Mater. Today, 2023, 66, 245–272.
19. W. J. Yang, R. Zhang, X. Guo, R. Ma, Z. Liu, T. Wang and L. Wang, J. Mater. Chem. A, 2022, 10, 23649–23665.
20. J. Liu, X. Chen, B. Sun, H. Guo, Y. Guo, S. Zhang, R. Tao, Q. Yang and J. Tang, J. Mater. Chem. A, 2022, 10, 25564–25574.
21. K. Kim, B. Kim and C. H. Lee, Adv. Mater., 2019, 32, 1904524.
22. Q. Wang, W. Qiu, M. Li, N. Li, X. Li, X. Qin, X. Wang, J. Yu, F. Li, L. Huang and D. Wu, Biomater. Sci., 2022, 10, 4796–4814.
23. J. Du, X. Zhan, Y. Xu, K. Diao, D. Zhang and S. Qin, J. Mater. Sci. Technol., 2025, 212, 251–258.
24. Y. Xu, M. Pei, X. Zhan, J. Du and D. Zhang, Prog. Org. Coat., 2024, 194, 108592.
25. T. Zhou, D. Zhang, K. Diao, J. Du, Y. Hu, Z. Lei, D. Liu, S. Liu and S. Qin, Mater. Today NANO, 2025, 29, 100606.
26. R. Yang, Y. Tan, T. Zhou, Y. Xu, S. Qin, D. Zhang and S. Liu, Polym. Compos., 2024, 45, 11044–11061.
27. H. Zhao, X. Yang, J. Sun, H. Lv, X. Liu, X. He, C. Jin and R. Che, J. Mater. Sci. Technol., 2025, 226, 196–204.
28. L. Xiao, Y. Hou, Z. Xue, L. Bai, W. Wang, H. Chen, H. Yang, L. Yang and D. Wei, Biomacromolecules, 2023, 24, 2087–2099.
29. L. Ye, L.-X. Liu, G. Yin, Y. Liu, Z. Deng, C.-Z. Qi, H.-B. Zhang and Z.-Z. Yu, Mater. Today Phys., 2023, 35, 101100–101110.
30. Z. Deng, T. Hu, Q. Lei, J. He, P. X. Ma and B. Guo, ACS Appl. Mater. Interfaces, 2019, 11, 6796–6808.
31. X. Wu, D. Kang, N. Liu, H. Shao, X. Dong and S. Qin, Sep. Purif. Technol., 2021, 278, 119523.
32. X. Lei, X. Zhang, A. Song, S. Gong, Y. Wang, L. Luo, T. Li, Z. Zhu and Z. Li, Composites, Part A, 2020, 130, 105762.
33. Q.-F. Guan, Z.-M. Han, K.-P. Yang, H.-B. Yang, Z.-C. Ling, C.-H. Yin and S.-H. Yu, Nano Lett., 2021, 21, 2532–2537.
34. W. Yang, B. Shao, T. Liu, Y. Zhang, R. Huang, F. Chen and Q. Fu, ACS Appl. Mater. Interfaces, 2018, 10, 8245–8257.
35. I. I. Marhoon, I. A. Atiyah and A. K. Rasheed, J. Alloys Compd., 2023, 969, 172229.
36. S. Vaidyanathan, J. Mater. Chem. C, 2023, 11, 8649–8687.
37. L. Tang, S. Wu, J. Qu, L. Gong and J. Tang, Materials, 2020, 13, 3947.
38. M. Gao, J. Li, X. Lu, R. Li, C. Hong, S. Zhao and G. Li, Inorg. Chim. Acta, 2024, 560, 121813.
39. H. Zhao, Y. Zhou, S. Cao, Y. Wang, J. Zhang, S. Feng, J. Wang, D. Li and D. Kong, ACS Mater. Lett., 2021, 3, 912–920.
40. H. Duan, H. Zhu, J. Yang, J. Gao, Y. Yang, L. Xu, G. Zhao and Y. Liu, Composites, Part A, 2019, 118, 41–48.
41. Z. Hu and B. Yan, J. Mater. Chem. A, 2023, 11, 4739–4750.
42. Y. Yu, P. Yi, W. Xu, X. Sun, G. Deng, X. Liu, J. Shui and R. Yu, Nano-Micro Lett., 2022, 14, 77.
43. L. Qin, C. Liu, J. Zhang, M. Xi, S. Pi, W. Guo, N. Li, S. Zhang and Z. Wang, J. Mater. Chem. C, 2023, 11, 1381–1392.
44. B. Xue, Z. Cheng, S. Yang, X. Sun, L. Xie and Q. Zheng, Composites, Part B, 2020, 203, 108467.
45. G. Hu, C. Wu, Q. Wang, F. Dong and Y. Xiong, Chem. Eng. J., 2022, 447, 137537.

---