Mechanically Tunable Three-Dimensional Elastomeric Network/Air Structures via Interference Lithography

Abstract

We show how to employ an interference lithographic template (ILT) as a facile mold for fabricating three-dimensional bicontinuous PDMS (poly(dimethylsiloxane)) elastomeric structures and demonstrate the use of such a structure as a mechanically tunable PDMS/air phononic crystal. A positive photoresist was used to make the ILT, and after infiltration with PDMS, the resist was removed in a water-based basic solution which avoided PDMS swelling or pattern collapse occurring during the ILT removal process. Since the period of the structure is approximately 1 microm, the density of states of gigahertz phonons are altered by the phononic PDMS/air crystal. Brillouin light scattering (BLS) was employed to measure phononic modes of the structure as a function of mechanical strain. The results demonstrate that the phononic band diagram of such structures can be tuned mechanically.

Three-dimensional nanonetworks for giant stretchability in dielectrics and conductors

“…Vacuum-assisted infi ltration provides a route to complete fi lling of PDMS prepolymer into the sub-micron pores of the 3D templates 15 . Spin-casting follows the infi ltration to fl atten the surface of the sample.…”

Compaction Through Buckling in 2D Periodic, Soft and Porous Structures: Effect of Pore Shape

“…Soft structures with deliberately designed patterns may significantly change their architecture in response to diverse stimuli [12,13], opening avenues for reconfigurable devices that change their shape to respond to or alter their environment. Two-dimensional periodic porous structures recently attracted considerable attention because of dramatic transformations of the original geometry observed as the results of mechanical instabilities [14,15,16].…”

Interface nano-confined acoustic waves in polymeric surface phononic crystals

“…This is consistent with values reported for longitudinal acoustic wave velocities for PDMS in the hypersonic frequency range. [24][25][26] These results are robust and independent from fabrication details, being the same in both the case of conformal-bonded and spin-coated PDMS-SPCs. 21 The emerging scenario for the main p-SPC resonance at 1.29 GHz is that of an acoustic wave (1) characterized by a strong interface confinement, (2) with an acoustic wavelength dictated by the PDMS-SPC periodicity, (3) living in the PDMS-SPC, and (4) longitudinally polarized in proximity of the interface, the acoustic wave propagation being assumed parallel to the interface as expected for an interface-confined mode.…”