Supporting data for impact of filler composition on mechanical and dynamic response of 3-D printed silicone-based nanocomposite elastomers

This research reports on the physical and mechanical effects of various filler materials used in direct ink write (DIW) 3-D printing resins. The data reported herein supports interpretation and discussion provided in the research article “Impact of Filler Composition on Mechanical and Dynamic Response of 3-D Printed Silicone-based Nanocomposite Elastomers” [1]. The datasheet describes the model structures and the interaction energies between the fillers and the other components by using Molecular Dynamics (MD) simulations. This report includes mechanical responses of single-cubic (SC) and face-centered tetragonal (FCT) structures printed using new DIW resin formulations (polydimethylsiloxane-based silicones filled with aluminum oxide, graphite, or titanium dioxide). Using MD simulations and mechanical data, the overall flexibility and interactions between resin components are fully characterized.

© 2020 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ ) Table   Subject Materials Science Specific subject area Preparation and characterization of 3-D printed silicone-based nanocomposite elastomers Type of data Image,

Value of the Data
• The data shows the mechanical responses of simple cubic (SC) and face-centered tetragonal (FCT) pads which are composed of polydimethylsiloxane-based polymers filled with aluminum oxide, graphite, or titanium dioxide. • This data can benefit researchers of materials in the field of formulation chemistry, polymer process engineering, additive manufacturing, and molecular dynamics simulation. • Guidelines for the mechanical characterization of hybrid composite materials are provided.

Data Description
This work provides the model structures acquired in molecular dynamics (MD) simulations to calculate the molecular interactions between the components in the composite resins, so that the two-layered models were built and equilibrated ( Fig. 1 and Table 1 Table 1 ).

Table 1
The interaction energies between the fillers and the other components calculated by molecular dynamics (MD) simulations. To calculate the interaction energy per gram, the densities (Al 2 O 3 /Graphite/TiO 2 = 3.2/2.2/4.23 g/cc) and the primary particle sizes were used.

Molecular dynamics (MD) simulations
Amorphous Cell module was used as a model builder. The models were geometrically optimized until their energies were stable, and were equilibrated by MD simulation with NVT (constant number of atoms, volume, and temperature) ensemble, in which the temperature was slowly increased from 0 K to 298 K in stepwise to avoid the calculation failure. The final production run for the interaction energy calculation was performed with NVT ensemble at 298 K and for 100 ps. In this simulation, we used Materials studio program package (BIOVIA Software Inc., CA, USA) and COMPASS II (Condensed-phase Optimized Molecular Potentials for Atomistic Simulation Studies II) force field were used as a force-field and force-field types and charges of all atoms were set to the default values [3][4][5] . Ewald and atom based summation method were used for electrostatic and van der Waals interactions, respectively.

Uniaxial compression and dynamic mechanical analysis
The compression test was performed using an ADMET eXpert 7601 testing system. Samples with dimensions of 2 × 2 cm were compressed for 4 cycles to a maximum stress of 1.0 MPa at a strain rate of 0.5%/sec. Dynamic mechanical analysis was performed in compression mode with a TA Instruments Q800 Dynamic Mechanical Analyzer (DMA), using 15-mm compression plates at ambient temperature ( ∼23 °C). Oscillatory strain sweeps were conducted at a frequency of 1 Hz to determine the linear viscoelastic regime for each sample. Subsequently, oscillatory frequency sweeps from 1 to 200 Hz were performed at strains within this regime; three cycles of each frequency sweep confirmed reproducibility.

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships which have, or could be perceived to have, influenced the work reported in this article.