The Degree of Polymerization, Surface Roughness, and Interactive Energy Impact Polymer Adsorption

1. The Degree of Polymerization, Surface Roughness, and Interactive Energy Impact Polymer Adsorption Aquil Frost, Environmental Engineering, Central State University Graduate Student Mentor: AbishekVenkatakrishnan John Lewnard, Mechanical Engineering, University of Cincinnati Faculty Mentors: Dr. Kelly Anderson and Dr. VikramKuppa Anne Shim, Biomedical Engineering, The Ohio State University Introduction Results Degree of Polymerization Surface Roughness Interactive Energy • 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. Density of Short Polymers on Surface A and Surface B Density of Short and Long Polymers on Surface A Density of Short Polymers on Surface A with varying Interactive Energies Surface A Surface B Method Figure 5: Density profile for surface A Figure 7: Density profile for short polymers Figure 9: Density profile for varying epsilons Polymer Generation using C Surface Generation using MATLAB Density of Long Polymers on Surface A and Surface B Density of Short and Long Polymers on Surface B Density of Short Polymers on Surface B with varying Interactive Energies Surface A Short Polymer Surface B Long Polymer Figure 1: Generated polymers Short Polymers: 42.5625 monomers per chain Long Polymers: 127.6875 monomers per chain Figure 2: Surface A Amplitude: 5 Å Wavelength: 25 Å Figure 3: Surface B Amplitude: 5 Å Wavelength: 37.5 Å Figure 6: Density profile for surface B Figure 8: Density profile for long polymers Figure 10: Density profile for varying epsilons Run Simulations using LAMMPS and VMD (Large-Scale Atomic/Molecular Massively Parallel Simulator and Visual Molecular Dynamics Conclusions • Controlled Variables • Polymer bond length • Polymer bond angle • Polymer density • Surface bond length • Ratio of surface atoms to surface area • Amplitude of surface • 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 • 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 4: Polymer adsorption onto a sinusoidal surface Acknowledgements Analyze Simulations • 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 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.