Dewetting transition

Very small sessile drops have a shape that depends on the line tension along the circular contact line if large enough it induces a dewetting transition detaching the drop from the surface [84]. 

Ashley KM, Raghavan D, Douglas JF, Karim A (2005) Wetting-dewetting transition line in thin polymer films. Langmuir 21 9518-9523... 

Julthongpiput D, Zhang W, Douglas JF, Karim A, Fasolka MJ (2007) Pattern-directed to isotropic dewetting transition in polymer films on micropattemed surfaces with differential surface energy contrast. Soft Matter 3 613-618... 

Liu P, Huang X, Zhou R, Berne BJ (2005) Observation of a dewetting transition in the collapse of the melitin tetramer. Nature 437 159-162... 

Choudhury, N. and B. M. Pettitt. 2007. The dewetting transition and the hydrophobic effect. Journal of the American Chemical Society. 129,4847. 

Krupenkin TN, Taylor JA, Wang EN, Kolodner P, Modes M, Salamon TR. (2007) Reversible wetting-dewetting transitions on electrically tunable supethydrophobic nanostructured surfaces. Langmuir 25 9128-9133. 

Fig. 6.6 A dewetting transition in the assembly of the four subunits of the water...

Hua L, Huang X, Liu P, Zhou R, Berne BJ (2007) Nanoscale dewetting transition in protein complex folding. J Phys Chem B 111 9069-9077... 

Anishkin A, Sukharev S (2004) Water dynamics and dewetting transitions in the small mechanosensitive channel MscS. Biophys J 86 2883-2895... 

IV.2. Dewetting Transition The cocoon is stable only if AF < 0, F = 0 defines a threshold depth he... 

Boreyko, J.B., CoUier, C.P., 2013. Dewetting transitions on superhydrophobic surfaces when are wenzel drops reversible J. Phys. Chem. C 117,18084. 

In cases when the two surfaces are non-equivalent (e.g., an attractive substrate on one side, an air on the other side), similar to the problem of a semi-infinite system in contact with a wall, wetting can also occur (the term dewetting appHes if the homogeneous film breaks up upon cooHng into droplets). We consider adsorption of chains only in the case where all monomers experience the same interaction energy with the surface. An important alternative case occurs for chains that are end-grafted at the walls polymer brushes which may also undergo collapse transition when the solvent quality deteriorates. Simulation of polymer brushes has been reviewed recently [9,29] and will not be considered here. 

Fig. 9 Optical micrographs of dewetted polystyrene droplets collected from points along a chemical gradient library. Scale bar (red) is approximately 20 um. As discussed in the text, this library was used to examine the transition between pattern directed dewetting (left micrographs) and isotropic dewetting from a homogeneous surface (right micrograph). (Reproduced with permission from [35])...

The bilayer morphology of thin asymmetric films of may be unstable. A regularly corrugated surface structure of the films was ascribed to spinodal transition into a laterally phase separated structure, where the surface morphology depended on the polymer incompatibility and the interfacial interactions [347, 348]. Recently, the phase separation and dewetting of thin films of a weakly incompatible blend of deuterated PS and poly(p-methylstyrene) have been monitored by SFM [349, 350]. Starting from a bilayer structure, after 454 h at T= 154 °C the film came to the final dewetting state where mesoscopic drops of... 

When adsorbed (from ambient air), water molecules might act as plasticizers and alter the dynamics of polymers. Moreover, water has a strong dipole moment and, consequently, dielectric active relaxation processes, which could partially occlude significant parts of the dielectric spectra of interest. Special attention to this effect has to be paid when the dynamics of thin polymer films is investigated, for example in relation to phenomena like the glass transition, dewetting, pattern formation, surface mobility etc. 

Fig. 4a—d. Lamellar structures in thin films that are not considered further in detail in the present article a Thin film confined between inequivalent walls, where the lower one favors the B-rich domains and the upper one the A-rich domains. Then an arrangement where the interfaces run parallel to the walls requires that thickness D and wavelength X are related as D=(n+1/2)A, n=0,l, 2... b Thin film on a substrate that favors B-rich domains undergo at the order-disorder transition (ODT) of the block copolymer melt a phase separation into a fraction x of thickness nXh and a fraction 1-x of thickness (n+1) Xh, such that D=[xn+(l-x) (n+l)] K if the air also favors B-rich domains, c If the air favors A-rich domains instead, the phase separation happens in a fraction x of thickness (n-l/2)A and a fraction 1-x of thickness (n+ 1/2)X with n= 1,2,3... d If the block copolymer film undergoes dewetting at the substrate, droplets form with a step-pyramide like structure ( Tower of Babel [30]). 

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