Abstract Strength and stiffness improvement without flexibility loss in shape-memory polymers is particularly significant in creating desirable functionality and broadening practical applications. Based on crystallinity tailoring strategy, a “rigidity-stretchability”-united approach is presented to construct shape-memory polyurethane composites (SMPUs) with specialized assembly for the integrated mechanical robustness and reliable deformability. Cellulose with different geometries were prepared as tailoring agent of crystallinity and structural modifier to assemble dual-networked structures of hybridized ionic- and hydrogen-bonding for the first time. Surface modification and morphology control of these celluloses were developed to manipulate the crystallization behaviors of soft segments in PU. Specifically, functionalized nanocrystal cellulose (f-NCC) with high crystallinity and needle-like geometry promoted a strong heterogeneous nucleation on the PU crystallization (the highest crystallinity, 31.3%) and contributed to 58% and 47% increase in tensile strength (48.9 MPa) and Young's modulus (237.2 MPa) without deteriorating the existent outstanding flexibility (emax = 756.14%), thereby featuring favorable shape memory and fluorescence. Furthermore, the f-NCC based films showed the highest shape memory properties (Rr = 99.7%, Rf = 99.4%) than functionalized cellulose from cotton pulps and functionalized microcrystal cellulose based ones. The “rigid-stretchable” unity of SMPUs would lay a significant foundation of applications in the fields of larger strain sensors and show great potential in information hiding and storage fields.

中文翻译：

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具有荧光的形状记忆复合材料的“刚性-可拉伸”统一性通过结晶度调整用于防伪应用

摘要 形状记忆聚合物在不损失柔韧性的情况下提高强度和刚度对于创造理想的功能和拓宽实际应用尤为重要。基于结晶度剪裁策略，提出了一种“刚性-拉伸性”联合方法来构建具有专门组装的形状记忆聚氨酯复合材料（SMPU），以实现综合机械强度和可靠的变形能力。制备了具有不同几何形状的纤维素作为结晶度和结构改性剂的剪裁剂，首次组装了杂化离子键和氢键的双网络结构。开发了这些纤维素的表面改性和形态控制，以控制 PU 中软链段的结晶行为。具体来说，具有高结晶度和针状几何形状的功能化纳米晶纤维素 (f-NCC) 促进了 PU 结晶的强烈异质成核（最高结晶度，31.3%），并有助于拉伸强度（48.9 MPa）增加 58% 和 47% 和杨氏模量 (237.2 MPa) 而不会降低现有出色的柔韧性 (emax = 756.14%)，从而具有良好的形状记忆和荧光。此外，基于 f-NCC 的薄膜比来自棉浆的功能化纤维素和基于功能化微晶纤维素的薄膜显示出最高的形状记忆特性（Rr = 99.7%，Rf = 99.4%）。SMPU 的“刚性-可拉伸”统一性将为大型应变传感器领域的应用奠定重要基础，并在信息隐藏和存储领域显示出巨大潜力。