1. 导读   木材轻质、可再生并具有天然的分级孔道，但本征绝缘性限制了其在电子器件、热管理和电磁防护中的应用。华南师范大学张振课题组通过纤维素纳米晶（cellulose nanocrystal，CNC）稳定液态金属（Liquid metal，LM）皮克林（Pickering）乳液，将高表面张力的块状液态金属转化为可进入木材孔道的纳米液滴；随后利用热压促使离散液滴变形、接触并形成连续导电网络，获得兼具高导电、低电压焦耳加热、电磁屏蔽、光热转换和力学增强的多功能导电木材。该成果以Multifunctional Liquid Metal-Infiltrated Conductive Wood Enabled by Cellulose Nanocrystal-Stabilized Pickering Emulsion为题发表在Chemical Engineering Journal （CEJ）上。2. 研究背景   木材由沿生长方向排列的细胞腔和细胞壁构成，天然拥有低密度、较高比强度以及连续的多尺度孔道，是承载功能组分的理想生物质骨架。然而，天然木材几乎不导电。现有碳化、导电聚合物浸渍、金属化和纳米导电涂层等方法，往往面临高温破坏木材结构、导电组分难以深度渗透、表面涂层易脱落或导电性能有限等问题。

  镓铟液态金属兼具金属级导电性、可变形性和环境稳定性，为构筑导电木材提供了新的材料选择。其难点也十分突出：液态金属表面张力极高，容易收缩成大尺寸球形液滴，即使在真空辅助条件下也难以进入木材内部。如何在温和条件下将液态金属细化、稳定并输送到木材深层孔道，是实现液态金属木材复合的关键。3. 设计思路    研究团队提出“木材孔道重构—CNC界面稳定—真空浸润—热压连通”的协同策略。首先，通过选择性去除半纤维素和木质素，构筑以纤维素为主体的多孔木材骨架。处理后，木材细胞腔平均直径增至50.28μm，细胞壁厚度降至1.02μm，孔道开放性、连通性和亲水性明显提高，为液态金属乳液的深度传输创造条件。随后，团队采用可再生、可商业获得的纤维素纳米晶作为皮克林乳化剂。在较短时间超声作用下，CNC吸附于液态金属液滴表面，形成平均粒径约341nm的稳定Pickering乳液。CNC壳层既通过空间位阻抑制液滴重新聚并，又可借助表面羟基与木材纤维素形成氢键，从而改善乳液与木材骨架之间的润湿和界面结合。

   在真空辅助浸渍过程中，CNC稳定的液态金属乳液不再是难以渗透的块状金属，而成为能够沿木材孔道输送的纳米液滴载体。经三次浸渍后，纤维素木材骨架中的液态金属质量分数达到59.3%，约为未处理轻木的2.25倍。乳液浸渍后的木材仍然绝缘，这是因为液态金属液滴被CNC层分隔。进一步在35℃、20MPa下热压，使木材孔道压缩、液滴发生形变并可能局部破壳、铺展和聚并，最终沿木材纵向建立连续的液态金属导电通路。

   这项工作的关键不只是把液态金属“装进”木材，更在于对液态金属形态进行可控切换。浸渍阶段需要液滴保持分散，才能顺利进入微米级孔道；导电阶段则需要液滴相互连通，才能降低接触电阻。CNC稳定层和热压处理分别服务于这两个看似矛盾的目标：前者实现液滴的小尺寸化、分散稳定和界面黏附，后者通过结构致密化促使液滴变形、局部破壳及邻近液滴接触，完成从“可浸润颗粒”到“连续导电网络”的转变。研究还揭示了材料结构与功能之间的可调关系。热压有利于液态金属网络连通，因而显著提升电导率、焦耳加热和电磁屏蔽性能；而保留离散纳米液滴和多孔结构，则更有利于近红外吸收和光热转换。这种结构—性能关联为后续针对不同场景选择“多孔光热态”或“致密导电态”提供了依据。

Figure 1. Schematic illustration of the preparation of multifunctional properties of conductive wood fabricated by infiltrating liquid metal via cellulose nanocrystal-stabilized Pickering emulsion with high electrical conductivity, Joule heating, photothermal conversion, EMI shielding, mechanical robustness, and flame resistance.

Figure 2. The optical and SEM images (cross- and vertical-sections) of (a) BW, (b) DW, and (d) CBW, respectively.

Figure 3. The (a) XRD, (b)FTIR, and (c) XPS survey spectra of BW, DW, and CBW, respectively. (d–f) High-resolution XPS C1s spectra of (d) BW, (e) DW, and (f) CBW.

Figure 4. (a) The digital photograph of LM on wood after vacuum-assist impregnation. (b) Mixture of LM and CNC aqueous dispersion, and CNC stabilized LM PE prepared by ultrasonication. (c) SEM images of CNC-stabilized LM PE. The wetting behaviors and absorbing time of LM PE with (d) BW, (e) DW, and (f) CBW.

Figure 5. LM mass evolution and loading capacity during successive infiltration cycles. (a) Mass and (b) LM mass fraction of BW@LM, DW@LM, and CBW@LM samples as a function of infiltration cycles.

Figure 6. The optical digital photographs and vertical-section SEM images of (a) CBW@LM and (b) DCBW@LM, respectively. (c) The SEM-EDS Ga and In element mapping of the cross-section of DCBW@LM. 4. 性能亮点电导率：DCBW@LM的电导率达到310.2Sm?1，约为未改性木材复合物的8.8倍；纵向电阻低至8.4Ω。

焦耳加热：在仅1.5V电压下，10s内由31.1℃升至58.3℃，60s达到65.2℃；10次加热—冷却循环保持稳定。电磁屏蔽：在X波段8.2–12.4GHz内，总屏蔽效能约为25–30dB，满足常用商业电子设备对屏蔽材料的基本需求；吸收贡献超过70%。近红外光热：未热压的CBW@LM保留分散液态金属液滴和多孔光捕获结构，在1.8Wcm?2下照射60s可升至143.7℃，并具有良好的短期循环稳定性。力学性能：热压导电木材的杨氏模量为847MPa，拉伸强度为12.7MPa，分别约为未加入液态金属的致密木材的2.87倍和2.15倍。耐火焰能力：在20s短时明火作用下保持整体宏观完整，未出现明显的大面积火焰蔓延、整体坍塌或快速烧穿。

Figure 7. LED circuit with (a) CBW@LM and (b) DCBW@LM as part of wires. (c) The electrical conductivity for DBW@LM, DDW@LM, and DCBW@LM measured by the four-probe method.

Figure 8. Joule heating performance of DCBW@LM. (a) Schematic of the Joule heating experiment set-up. (b) Real-time infrared thermal images showing the surface temperature of DCBW@LM. (c) Time-dependent temperature profiles under different applied voltages (0.6, 0.9, 1.2, and 1.5 V). (d) The saturated temperature as a function of the square of the voltage (U2). (e) The current as a function of applied voltage. (f) Cyclic stability test over 10 heating–cooling cycles at 1.5 V.

Figure 9. EMI shielding performance of DBW, DDW@LM, DCBW@LM in the X-band (8.2–12.4 GHz). (a) SET of DBW, DDW@LM, and DCBW@LM as a function of frequency. (b) Frequency-dependent SET, SEA, and SER of DCBW@LM. Comparison of (c) SEA and (d) SER for DBW, DDW@LM, and DCBW@LM across the X-band.

Figure 10. Photothermal conversion performance of CBW@LM and DCBW@LM under NIR irradiation. Infrared thermal images showing the surface temperature of (a) CBW@LM and (b) DCBW@LM after NIR irradiation of 60s under varying power densities (0.6, 1.0, 1.4, and 1.8 W/cm2), respectively. (c, f) Real-time temperature evolution curves for (c) CBW@LM and (f) DCBW@LM under different NIR power densities. (d, g) Heating-cooling cycle curves for (d) CBW@LM and (g) DCBW@LM under NIR at 1.4 W/cm2. (e, h) Comparison of real-time temperature profiles between the 1st and 10th heating–cooling cycles for (e) CBW@LM and (h) DCBW@LM under NIR at 1.4 W/cm2.

Figure 11. (a) Tensile stress–strain curves of DCBW and DCBW@LM. (b) Comparison of the Young’s modulus and ultimate tensile strength of DCBW and DCBW@LM. (c) Photographs showing the overall states of DCBW@LM after flame exposure for different durations. (d) Surface morphology images of DCBW@LM after flame exposure at each time point, where the red-boxed region indicates progressively deepened local darkening during burning.5. 研究意义与应用前景   该研究将可再生木材的天然分级孔道、CNC的颗粒乳化能力与液态金属的高导电性有机结合，绕开了块状液态金属难浸润和传统表面导电层易脱落的问题。所得材料并非追求单一性能极值，而是在导电、热响应、电磁防护、力学强度和短时耐火焰能力之间实现较均衡的功能集成。更广泛地看，“颗粒稳定乳液输送功能相—压力触发网络重构”的方法不仅适用于木材，也有望拓展到纤维素气凝胶、海绵及其他天然或人工多孔骨架。相关材料在智能建筑、低电压加热器、热管理、电磁防护和可持续电子器件等方向具有潜在应用价值。6. 论文信息Lili Li#, Liu Feng#, Zhengmao Ye, Jiezhi Huang, Hui Peng, Xuejin Zhang*, Jia Kong*, Ping Lan*, Guofu Zhou, Zhen Zhang*. Multifunctional Liquid Metal-Infiltrated Conductive Wood Enabled by Cellulose Nanocrystal-Stabilized Pickering Emulsion. Chemical Engineering Journal 2026, 182088. https://doi.org/10.1016/j.cej.2026.182088