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The Degree of Polymerization, Surface Roughness, and Interactive Energy Impact Polymer Adsorption. Aquil Frost, Environmental Engineering, Central State UniversityGraduate Student Mentor: Abishek Venkatakrishnan - PowerPoint PPT Presentation
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Aquil Frost, Environmental Engineering, Central State University Graduate Student Mentor: Abishek VenkatakrishnanJohn Lewnard, Mechanical Engineering, University of Cincinnati Faculty Mentors: Dr. Kelly Anderson and Dr. Vikram KuppaAnne Shim, Biomedical Engineering, The Ohio State University
The Degree of Polymerization, Surface Roughness, and Interactive Energy Impact Polymer Adsorption
Introduction• Polymer adsorption onto surfaces is an important process in many applications of products such as
adhesives, paints, and plastics.• Simulations have been run to study the adsorption of polymers onto completely smooth surfaces,
though all surfaces are rough on the nano-scale.• The goal of this research is to find whether the degree of polymerization, surface roughness,
and/or interactive energy effect polymer adsorption in order to better explain the macro-scale properties of polymer adsorption.
Method
Conclusions
Acknowledgements
Results
Polymer Generation using C Surface Generation using MATLAB
Run Simulations using LAMMPS and VMD(Large-Scale Atomic/Molecular Massively Parallel Simulator and Visual Molecular Dynamics
Analyze Simulations
Controlled Variables• Polymer bond length• Polymer bond angle• Polymer density• Surface bond length• Ratio of surface atoms to surface
area• Amplitude of surface
We would like to thank the University of Cincinnati, in conjunction with the National Science Foundation, for funding this program. We would also like to thank our faculty mentors and graduate student mentor for their guidance and support.
Degree of Polymerization Surface Roughness Interactive Energy
0.0 10.420.931.341.752.262.673.183.593.90
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Distance from Surface (Å)
Den
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g/cc
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Short Polymer
Long Polymer
0.0 12.925.838.751.664.577.390.20
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Distance from Surface (Å)
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Density of Short and Long Polymers on Surface A
Short Polymer
Long Polymer
Density of Short and Long Polymers on Surface B
Independent Variables• Degree of polymerization• Wavelength of surface• Interactive energy parameter
Dependent Variables• Degree of adsorption, measured
by the polymer’s distance from the surface
• Density profile compiled for each polymer-surface system• Average center of mass calculated for each chain length in each polymer-surface system• Polymer lengths, surface types, and interactive energies compared to find adhesion properties
• With high degree of polymerization : increased surface roughness caused decreased adsorption. • With low degree of polymerization : increased surface roughness caused increased adsorption.
• With high surface roughness: increased degree of polymerization caused decreased adsorption. • With low surface roughness: increased degree of polymerization caused increased adsorption.
• Increasing the interactive energy parameter caused increased adsorption universally.
Figure 1: Generated polymersShort Polymers: 42.5625 monomers per chainLong Polymers: 127.6875 monomers per chain
Figure 4: Polymer adsorption onto a sinusoidal surface
Figure 5: Density profile for surface A
Figure 6: Density profile for surface B
0.0 10.420.931.341.752.262.673.183.593.90
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Density of Short Polymers on Surface A and Surface B
Figure 7: Density profile for short polymers
Surface A
Surface B
0.0 10.420.931.341.752.262.673.183.593.90
0.020.040.060.08
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Distance from Surface (Å)
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Density of Long Polymers on Surface A and Surface B
Figure 8: Density profile for long polymers
Surface A
Surface B
Figure 2: Surface AAmplitude: 5 ÅWavelength: 25 Å
Figure 3: Surface BAmplitude: 5 ÅWavelength: 37.5 Å
0.0 10.220.530.740.951.261.471.681.992.10
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Distance from Surface (Å)
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ε = 0.0935
ε = 0.2805
ε = 0.187
Figure 9: Density profile for varying epsilons
Density of Short Polymers on Surface A with varying Interactive Energies
0.0 10.220.530.740.951.261.471.681.992.10
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ε = 0.0935
ε = 0.187
ε = 0.2805
Figure 10: Density profile for varying epsilons
Density of Short Polymers on Surface B with varying Interactive Energies
