Elasticity patterns induced by phase-separation in polymer blend films

Abstract

Systematical studies on the impact of the thickness of thin films composed of polystyrene (PS) or poly(ethylene oxide) (PEO) on the effective elasticity of polymer-decorated soft polydimethylsiloxane substrate were performed. For both investigated polymer films, elasticity parameter was determined from force-displacement curves recorded using atomic force microscopy. Effective stiffness of supported film grows monotonically with film thickness, starting from the value comparable to the elasticity of soft support and reaching plateau for polymer layers thicker than 200 nm. In contrary, for films cast on hard support no significant thickness dependence of elasticity was observed and the value of elasticity parameter was similar to the one of the substrate. Based on these results, non-conventional method to produce elasticity patterns of various shapes and dimensions induced by phase-separation process in symmetric and asymmetric PS:PEO blend films on soft support was demonstrated. Elevated PS domains were characterized by elasticity parameter 2 times higher than lower PEO matrix. In contrary, adhesion force was increased more than 3 times for PEO regions, as compared to PS areas.

Programmable microscale stiffness pattern of flat polymeric substrates by temperature-memory technology

“…Polymeric substrates comprising local mechanical stiffness pattern or nanostructural features are intensively investigated in the context of applications such as haptic displays (touchpads), stretchable electronics, mechanical and optical data storage devices, [1][2][3][4][5][6][7][8] or as instructive cell substrates guiding mechanosensitive (stem) cells. [9][10][11][12][13][14][15] While individual cells can react to structural features of few nanometers in size and mechanical differences in the Pascal (Pa) range, [9,14] the tactile sensitivity of a human finger is only capable of detecting structural features above 10 nm and local mechanics in the kPa regime.…”

“…[9][10][11][12][13][14][15] While individual cells can react to structural features of few nanometers in size and mechanical differences in the Pascal (Pa) range, [9,14] the tactile sensitivity of a human finger is only capable of detecting structural features above 10 nm and local mechanics in the kPa regime. [16][17][18][19][20] Mechanically patterned surfaces can be realized by variation of the polymer's chemical composition (e.g., phase separated blends) [2] or crosslinking density (e.g., hydrogels). [9,21] Another approach is based on placing rigid microstructures or defined closed cavities (pores) [22] under soft/elastic polymeric materials and applying pressure.…”

Effect of Substrate Stiffness on Physicochemical Properties of Normal and Fibrotic Lung Fibroblasts

“…The stiffness of the substrate is known to impact adhesion and proliferation of cells [ 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. Our previous research, performed for PDMS elasticity changing stepwise from 600 kPa to 1.5 MPa, showed that substrate stiffness affects the behavior of normal and IPF-derived fibroblasts, influencing the number, shape, and arrangement of cells after 72 h culturing [ 35 ].…”