Combinatorial Materials Science for Polymer Thin-Film Dewetting

Abstract

Combinatorial methods involving data collection in multiparameter space allow a rapid identification of measured property trends as a function of system parameters. The technique has been applied with success to pharmaceutical, inorganic and organic materials synthesis, but not significantly to measurements of polymeric films and coatings. We demonstrate the use of 2-D combinatorial libraries to investigate thin-film dewetting. We have prepared libraries of thin films of polystyrene on silicon substrates containing orthogonal, continuous variations of thickness (h), and temperature (T) that represent about 1200 practical state points per library. The libraries were screened for dewetting behavior using automated optical microscopy. Dewetting trends were visibly apparent on the libraries, and a comprehensive map of the T, h, and time (t) dependence was generated in a few hours. The combinatorial libraries, spanning a large T, h, and t range, not only reproduced known dewetting structures and phenomena but also enabled a novel T, h superposition of the heterogeneous nucleated hole dewetting kinetics. We observed three hole nucleation regimes as a function of thickness: heterogeneously nucleated holes (h > 55 nm), a crossover regime where both heterogeneous and capillary instability nucleation compete (33 nm < h < 55 nm), and a regime of holes nucleated by capillary instability (16 nm < h < 33 nm).

Deformation and dewetting of thin liquid films induced by moving gas jets

“…7d illustrates a measurement close to that transition point. The power law N H $ h À4 min for low values of h min is close to the experimental observations on thin films of polystyrene on silicon wafers [18][19][20]22,27] and is consistent with our earlier analysis of 3EG on PC (see Fig. 6d for Re D > 100 in Ref.…”

“…Above a critical translation speed, however, a thin liquid film is left on the wafer, that spontaneously breaks up, dewets and leads to undesirable residual droplets on the substrate. Similar film rupture and dewetting phenomena have been described for thin layers of polymer melts [18][19][20][21][22][23][24][25][26][27], metals [28][29][30][31][32] and oil films submersed in water [33][34][35].…”

Integration of MALDI-TOFMS as high-throughput screening tool into the workflow of combinatorial polymer research

“…Examples of such tailor-made HTS techniques include, for instance the fast determination of molar mass and molar mass distribution by rapid gel permeation chromatography, 11 the wettability of polymer libraries, 12 or the morphology of polymer gradient libraries. 13,14 However, until recently no feasible technique was described for the high-throughput determination of molar masses, molar mass distributions as well as of end-groups of synthetic polymers by mass spectrometry. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry ͑MALDI-TOFMS͒ has advanced to the perhaps most powerful MS tool for the analysis of polymers 15 since its introduction in the 1980s.…”

Long-range correlated dynamics in ultra-thin molecular glass films

“…Despite these difficulties the effective viscosity can be indirectly measured by investigating the temperature dependence of the characteristic dewetting time, τ dewetting [34]. This is because substrate interactions, surface tension, and the film's initial morphology are all weak functions of temperature, leaving the film's effective viscosity as the only temperature-dependent parameter driving dewetting (more details in SI).…”