Effect of linear elongation of PDMS-supported polyelectrolyte multilayer determined by attenuated total reflectance...

Polyelectrolyte multilayers (PEMs) deposited on flexible supports, such as silicone rubber, show interesting properties upon elongation and release, like controlled wrinkling, elongation-based wetting, or dewetting and stimuli responsive nanovalves. To understand the underlying physical effects of PEM experiencing linear elongation, the orientation change of molecular groups within PEM experiencing linear elongation was investigated. The model PEM consists of polystyrenesulphonate and polydimethyldiallyl chloride. The investigation method was infrared attenuated total reflectance. In the study, the orientation change of the benzene and the sulfate groups of polystyrenesulphonate upon elongation of the PEM, prepared at high and low ionic strengths, was tracked. The gained results show that the benzene group shows no sign of orientation change upon elongation, whereas the sulfate group does, whereby the reorientation depends on the ionic strength of the preparation solution. Upon release of elongation, the PEM prepared at low ionic strength shows no orientation change, whereas PEM prepared at high ionic strength does show further orientation change, indicating that the formed wrinkles elongate the PEM on the top of the wrinkles.