Mesoscopic Patterning in Thin Polymer Films Formed under the Fast Dip‐Coating Process

Abstract

SummaryMesoscopically ordered self-assembled polystyrene, polycarbonate and polymethylmethacrylate films were obtained when polymer solutions were deposited on vertical plates and dried with hot air. It was shown that characteristic size (~ 50 µm) of the mesoscopic cell is practically insensitive to the polymer or substrate kind, while the thickness of the substrate plays a decisive role in the mesoscopic patterning.Junction angles of 120° and 90° were observed. Marangoni instability plays an important role in the cell's structure formation. A semi-quantitative model explaining the phenomenon of mesoscopic cell formation is proposed.

Pinning, Retraction, and Terracing of Evaporating Droplets Containing Nanoparticles

“…The latter works have demonstrated the development of rings in the drying of coffee drops and films containing latex particles [35][36][37], the formation of rings [43][44][45] and tree-like structures [46] in nanoparticulate thin evaporating films of binary mixtures of nitrocellulose in amyl acetate and hexadecylamine in hexane, complex stain morphologies in crystallising droplets [38], stick-slip motion [41], and fingering phenomena in dewetting films of nanofluids [40,42]. (There are also related studies that examine the patterns formed during the evaporation of drops and films of polymer solutions [47][48][49].) Yet, in spite of this large number of studies, to the best of our knowledge, none of these has modelled the flow dynamics in the simultaneous presence of structural forces and phase change effects.…”

Route to create large-area ordered polymeric nanochannel arrays

“…[3][4][5][6][7][8] However, the preparation of special types of surface pattern, such as polymer nanochannels on top of solid supports, by the use of self-assembly is rather difficult. Polymer nanochannels are best described, by the alignment of polymeric material in parallel walls, without a polymeric connection in the perpendicular direction.…”

Teflon AF2400/Ultem composite hollow fiber membranes for alcohol dehydration by high‐temperature vapor permeation

“…Then, the concentration gradient leads to the surface tension-driven Marangoni instability that normally generates the honeycomb-like microstructure pattern. [44][45][46] Second, air humidity and evaporative cooling favor the formation of water droplets in the Teflon AF2400 solution, which serve as soft templates and lead to the formation of a wellordered and honeycomb-like pattern. 47 When the Teflon AF2400 concentration is lower (i.e., 0.25 and 0.5 wt %), the Teflon AF2400 layer cannot fully cover the surface of Ultem HFs as shown in Figure 4.…”