Published: March 29, 2016
Lewis M. Cox, Jason P. Killgore, Zhengwei Li, Rong Long, Aric W. Sanders, Jianliang Xiao, Yifu Ding
Formulations and applications of micro- and nano-scale polymer particles have proliferated rapidly in recent years, yet knowledge of their mechanical behavior has not grown accordingly. In this study we examine the ways that compressive strain, substrate surface energy, and particle size influence the shape memory cycle of polystyrene particles. Using nanoimprint lithography, differently sized particles are programmed into highly deformed, temporary shapes in contact with substrates of differing surface energies. Atomic force microscopy is used to obtain in situ measurements of particle shape recovery kinetics and scanning electron microscopy is employed to assess differences in the profiles of particles at the conclusion of the shape memory cycle. Finally, finite element models are used to investigate the growing impact of surface energies at smaller length scales. Results reveal that the influence of substrate adhesion on particle recovery is size-dependent, and can become dominating at sub- micron length scales.
Pub Type: Journals
Shape Memory, Microparticles, Nanoparticles, Atomic Force Microscopy, Mechanical Properties
Created March 29, 2016, Updated September 17, 2018