Angulo-Cervera José Elias, Piedrahita-Bello Mario, Martin Baptiste, Alavi Seyed Ehsan, Nicolazzi William, Salmon Lionel, Molnár Gábor, Bousseksou Azzedine
LCC, CNRS & University of Toulouse 205 route de Narbonne 31077 Toulouse France
Mater Adv. 2022 May 23;3(12):5131-5137. doi: 10.1039/d2ma00459c. eCollection 2022 Jun 20.
Polymer composites of molecular spin crossover complexes have emerged as promising mechanical actuator materials, but their effective thermomechanical properties remain elusive. In this work, we investigated a series of iron(ii)-triazole@P(VDF-TrFE) particulate composites using a tensile testing stage with temperature control. From these measurements, we assessed the temperature dependence of the Young's modulus as well as the free deformation and blocking stress, associated with the thermally-induced spin transition. The results denote that the expansion of the particles at the spin transition is effectively transferred to the macroscopic composite material, providing 1-3% axial strain for 25% particle load. This strain is in excess of the 'neat' particle strain, which we attribute to particle-matrix mechanical coupling. On the other hand, the blocking stress (∼1 MPa) appears reduced by the softening of the composite around the spin transition temperature.
分子自旋交叉配合物的聚合物复合材料已成为有前途的机械致动器材料，但其有效的热机械性能仍不明确。在这项工作中，我们使用带温度控制的拉伸测试平台研究了一系列铁（II）-三唑@聚（偏二氟乙烯-三氟乙烯）颗粒复合材料。通过这些测量，我们评估了杨氏模量以及与热诱导自旋转变相关的自由变形和阻塞应力的温度依赖性。结果表明，自旋转变时颗粒的膨胀有效地传递到宏观复合材料上，对于25%的颗粒负载可提供1-3%的轴向应变。这种应变超过了“纯”颗粒应变，我们将其归因于颗粒-基体的机械耦合。另一方面，在自旋转变温度附近，复合材料的软化似乎降低了阻塞应力（约1MPa）。
