Additional Funding Sources

This research is part of the Blue Waters sustained-petascale computing project, which is supported by the National Science Foundation awards OCI-0725070 and ACI-1238993, as well as the state of Illinois. Blue Waters is a joint effort of the University of Illinois at Urbana-Champaign and its National Center for Supercomputing Applications. This work used the computing resources supported by Boise State College of Engineering Information Technology services. We would also like to acknowledge additional support through National Science Foundation project NSF-DMR 1710640.

Abstract

Tiny pumps that can deliver microliters of fluid against high back-pressures can be made from Ni-Mn-Ga alloys. The fluid is transported in a movable pocket made between the alloy and a surrounding seal material, enabled by the magnetic shape memory properties of the alloy. The interaction between the sealant and the alloy is therefore critical, in particular how hey adhere and delaminate during pumping. This simulation study aims to quantify the interactions between the sealant poly-dimethylsiloxane (PDMS) and the Ni-Mn-Ga alloy. To study these PDMS-alloy interfaces, molecular dynamics simulations are performed using HOOMD-Blue on graphics processing units. We develop atomistic models for the interface components and investigate how the adhesion of short PDMS chains on Ni-Mn-Ga depend on model parameters, and temperature. We measure simulation speed as a function of system size on different processors to determine limits to computational feasibility and we identify conditions that facilitate adhesion. These simulations provide a first step towards more detailed studies of such organic/alloy interfaces and may help to identify more optimal sealant chemistries in the future.

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Molecular Interactions of Polydimethylsiloxane and Ni-Mn-Ga

Tiny pumps that can deliver microliters of fluid against high back-pressures can be made from Ni-Mn-Ga alloys. The fluid is transported in a movable pocket made between the alloy and a surrounding seal material, enabled by the magnetic shape memory properties of the alloy. The interaction between the sealant and the alloy is therefore critical, in particular how hey adhere and delaminate during pumping. This simulation study aims to quantify the interactions between the sealant poly-dimethylsiloxane (PDMS) and the Ni-Mn-Ga alloy. To study these PDMS-alloy interfaces, molecular dynamics simulations are performed using HOOMD-Blue on graphics processing units. We develop atomistic models for the interface components and investigate how the adhesion of short PDMS chains on Ni-Mn-Ga depend on model parameters, and temperature. We measure simulation speed as a function of system size on different processors to determine limits to computational feasibility and we identify conditions that facilitate adhesion. These simulations provide a first step towards more detailed studies of such organic/alloy interfaces and may help to identify more optimal sealant chemistries in the future.