Miniaturization of Patterns in Thin Elastic Film
Surita Basu (Prof. Jayati Sarkar)
11 th October 2017, Wednesday, 04:00‐04:30 pm (25+5 mins), ChE Seminar hall
Thin films are of paramount interest in daily life. Spontatneous pattern formation through self-organization in these thin films are of more advanced importance. The patterns formed in this technique in case of soft thin elastic film are due to the the combative nature between the attractive van der Waal force of attraction between the film and an approaching contactor and the restoring elastic forces intrinsic to these films. In comparison to the traditional lithographic techniques this method of self-organization is more cost effective, covers large area, involves low equipment costs, gives rise to high throughputs and offers high flexibility. The micro and nano patterns, thus, formed on the thin film surface can be used in microelectronics and has potential to be used in other technological applications as well; such as in lab-on- chip devices for biomedical purposes, in preparation of coatings and adhesives as functional and self-cleaning materials, in formation of various scaffolds for tissue engineering, in solar cells and batteries, in optical device transistors and in many more such applications. Miniaturization of these patterns further increases the applicability since this leads to enhanced functionality of the surfaces. It has been observed theoretically that the wavelength of the engendered surface patterns reduces when casted over a patterned substrate. With inspiration from the finite element work, different types of substrates varying from having very rough to very regularly ordered structures having different amplitude to film thickness ratios have been considered in the present study to create miniature surface patterns in these soft thin elastic films. Economical and low cost methods of pattern substrate creation have been employed. Inherent roughnesses in naturally occurring water lily leaves to low-cost commercially available compact disks are used as templates to create totally rough to sinusoidally patterned substrates. The main aspiration of the study remains in showing through different types of patterns that the pattern-amplitudes actually have miniaturizing effects on the engendered surface patterns formed during adhesion and debonding. The patterns formed has been found to have a great emphasis on removal of oil from oil-water emulsion.