title: Mechanically programmed shape change in laminated elastomeric composites.
abstract: Soft, anisotropic materials, such as myocardium in the heart and the extracellular matrix surrounding cells, are commonly found in nature. This anisotropy leads to specialized responses and is imperative to material functionality, yet few soft materials exhibiting similar anisotropy have been developed. Our group introduced an anisotropic shape memory elastomeric composite (A-SMEC) composed of non-woven, aligned polymer fibers embedded in an elastomeric matrix. The composite exhibited shape memory (SM) behavior with significant anisotropy in room-temperature shape fixing. Here, we exploit this anisotropy by bonding together laminates with oblique anisotropy such that tensile deformation at room temperature - mechanical programming - results in coiling. This response is a breakthrough in mechanical programming, since non-affine shape change is achieved by simply stretching the layered A-SMECs at room temperature. We will show that pitch and curvature of curled geometries depend on fiber orientations and the degree of strain programmed into the material. To validate experimental results, a model was developed that captures the viscoplastic response of A-SMECs. Theoretical results correlated well with experimental data, supporting our conclusions and ensuring attainability of predictable curling geometries. We envision these smart, soft, shape changing materials will have aerospace and medical applications.
authors.affiliation: Syracuse Biomaterials Institute and Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY 13244, USA. ptmather@syr.edu.
authors.forename: Jaimee M
authors.initials: JM
authors.lastname: Robertson
authors.forename: Amir H
authors.initials: AH
authors.lastname: Torbati
authors.forename: Erika D
authors.initials: ED
authors.lastname: Rodriguez
authors.forename: Yiqi
authors.initials: Y
authors.lastname: Mao
authors.forename: Richard M
authors.initials: RM
authors.lastname: Baker
authors.forename: H Jerry
authors.initials: HJ
authors.lastname: Qi
authors.forename: Patrick T
authors.initials: PT
authors.lastname: Mather
mesh_terms: D016880:Anisotropy; D001672:Biocompatible Materials / Q000737:chemistry*; D004548:Elasticity; D020724:Elastomers / Q000737:chemistry*; D005109:Extracellular Matrix / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D013314:Stress, Mechanical
chemical_list: D001672:Biocompatible Materials; D020724:Elastomers; D011108:Polymers