Supporting Information Significantly High Thermal Rectification in an Asymmetric Polymer Molecule Driven by Diffusive versus Ballistic Transport Hao Ma 1 and Zhiting Tian 1, 2 ∗ 1 Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA 2 Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, USA Choosing a Heat Bath Figure S1. The same tapered bottlebrush polymer device (n=18 and m=18:1:1) with different sizes of heat baths. (a) SS contact: Only backbone atoms are used for the heat baths and each heat bath contains 40 atoms; (b) LS contact: Side chains are also included in heat baths. Red and blue denote heat bath; black denotes fixed boundary; green denotes the backbone chain, and pink denotes the side chains. There are different choices of thermal contacts: SS contact denotes that the surface areas of the two thermal contacts are the same and narrow; LS contact denotes that the surface areas of thermal contacts match the areas of both the wide and narrow ends of the device. We carefully chose the SS contact (Figure S1a) for all the simulations. Note that our LS contact (Figure S1b) is not the same as described by Lee et al. 1 because our side-chain atoms are not covalently ∗ Corresponding author. Electronic mail: zhiting@vt.edu