Topology-Optimized Kirigami Design of Electrospun BNNS/PVA Composite Films for Flexible Electronics Thermal Management

Flexible electronics require thermal-management materials that can efficiently dissipate heat while maintaining mechanical compliance under deformation. In this study, a topology-optimized kirigami BNNS/PVA composite film was developed by combining boron nitride nanosheet incorporation, electrospinning, and thermo-mechanical topology optimization. The electrospun BNNS/PVA network enhanced the in-plane thermal conductivity from 0.19 to 4.63 W/(m·K), while the optimized kirigami architecture improved deformation accommodation by reducing elastic strain energy accumulation. The average temperature and total elastic strain energy were reduced from 86 °C to 53 °C and from 43 J to 11 J, respectively. The optimized structure achieved a maximum stress of 2.39 MPa and a maximum strain of 5.02% and reduced the steady-state temperature by up to 21.27 °C under identical heating conditions. Furthermore, in-plane thermal conductivity was maintained after 300 bending cycles, which provides an effective material–structure design strategy for flexible electronic thermal management applications.