From: Bioinspired Graphene Nanogut Date of download: 10/10/2017 Copyright © ASME. All rights reserved. From: Bioinspired Graphene Nanogut J. Appl. Mech. 2013;80(6):061009-061009-6. doi:10.1115/1.4023641 Figure Legend: Simulation setting up and procedure. (a) Schematic figure of the system composed of a combination of a graphene ribbon and a carbon nanotube (CNT). The diameter of the CNT is d, the width of the graphene ribbon is w, the system total length is L, and the graphene ribbon is initially εL shorter than the carbon nanotube (where ε is the mismatch strain). The step-by-step simulation procedure is summarized in (b)–(d). (b) Atomistic geometry of one of the structures considered in our study. The CNT is (3,3) tube with d = 4.1 Å, the graphene ribbon is w = 15 Å, and the total length is L = 1000 Å (which is partly shown here by snapshots). The distance between the edges of the CNT and the graphene ribbon is initially 10 Å. The edges are functionalized by hydroxyl groups with the purpose of forming hydrogen bonds as a glue between the two components. As the simulation starts, the graphene ribbon is subjected to tensile strain of ε such that it reaches the same length as the CNT. (c) Graphene with prescribed strain is displaced by 8 Å in the y direction. We fix the two ends of the graphene ribbon and relax other parts of the system. The inset shows a segment with details. The hydrogen bonds are depicted in (b)–(c) by dashed lines. (d) Geometry after all constraints are removed and the system is fully relaxed. The inserted figure on the right shows the morphology of loops in the chick's gut at embryonic day 12 taken from Ref. [15] at a length-scale 106 times larger than our nanogut system (adapted and reprinted from Ref. [15] with permission from Nature Publishing Group Copyright 2011).

From: Bioinspired Graphene Nanogut Date of download: 10/10/2017 Copyright © ASME. All rights reserved. From: Bioinspired Graphene Nanogut J. Appl. Mech. 2013;80(6):061009-061009-6. doi:10.1115/1.4023641 Figure Legend: Geometry profile of the (3,3) CNT axis as a function of simulation time. (a) Snapshots of the evolution of the geometry of the (3,3) CNT with d = 4.1 Å, ɛ = 0.2, and w = 15 Å during equilibration. The CNT axis is represented by a series of beads. The coordinate of each bead is given by the mass center of 50 neighboring carbon atoms. (b) RMSD of the all axis beads as a function of equilibration time. It is noted there is a significant jump at ∼10 ps. The simulation snapshots in panel (a) are denoted by arrows. (c) Distance profiles of the axis beads from the end-to-end connection line at different equilibration times (h as show in (a) for snapshot at 170 ps). (d) Average contour length of the loop period as a function of equilibration time for different temperatures. (e) Average radius and standard deviation at the maximum amplitude as a function of equilibration time for different temperatures.

From: Bioinspired Graphene Nanogut Date of download: 10/10/2017 Copyright © ASME. All rights reserved. From: Bioinspired Graphene Nanogut J. Appl. Mech. 2013;80(6):061009-061009-6. doi:10.1115/1.4023641 Figure Legend: Measured geometric parameters of wavy shapes of CNT-graphene ribbon systems at equilibrium. (a) Contour length of a loop period as a function of the CNT diameter. The linear curve is fitted according to Eq. (4) and data points with d < 6.8 Å. (b) Radius of the loop at the maximum amplitude as a function of the CNT diameter and prescribed strain. The linear curve is fitted according to Eq. (5) and data points with d < 6.8 Å.

From: Bioinspired Graphene Nanogut Date of download: 10/10/2017 Copyright © ASME. All rights reserved. From: Bioinspired Graphene Nanogut J. Appl. Mech. 2013;80(6):061009-061009-6. doi:10.1115/1.4023641 Figure Legend: Snapshots of carbon nanotubes in their initial state and at equilibrium. (a) Geometries of a (3,3) CNT (d = 4.1 Å, ɛ = 0.2, w = 28 Å), top view (left) and the shape of the cross-section. The upper snapshots show the initial geometry, and the lower snapshots show the geometry at equilibrium. (b) Geometries of CNT (5,5) (d = 6.8 Å, ɛ = 0.2, w = 28 Å), top view (left) and the shape of the cross-section (right). The upper snapshots depict the initial geometry, and the lower snapshots show the geometry at equilibrium. The graphene ribbon and the hydroxyl groups are not shown in those snapshots for clarity. (c) Total energy and number of hydrogen bonds per unit length as functions of simulation time for a (5,5) CNT (d = 6.8 Å, ɛ = 0.2, w = 28 Å). (d) Total energy and number of hydrogen bonds per unit length as functions of the simulation time for a (3,3) CNT (d = 4.1 Å, ɛ = 0.2, w = 28 Å).