Pattern Replication by Confined Dewetting

Harkema, Stephan; Schäffer, Erik; Morariu, M.; Steiner, Ullrich

doi:10.1021/la034527b

Cited by 57 publications

(58 citation statements)

References 34 publications

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“…Confinement of a soft liquid [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] or a soft solid surface by external fields and residual stresses [11,12,33,34] often engenders the surface instability and self-organized patterning of the film surface. Such instabilities can also be often controlled and guided, [3][4][5][6]9,10,[12][13][14][15][16][17]28,[36][37][38][39] which may allow their potential technological use in the applications involving meso-scale patterning of soft materials.…”

Section: Introductionmentioning

confidence: 99%

“…Such instabilities can also be often controlled and guided, [3][4][5][6]9,10,[12][13][14][15][16][17]28,[36][37][38][39] which may allow their potential technological use in the applications involving meso-scale patterning of soft materials. Of particular interest here is the surface of a soft thin elastic film, which, when brought in adhesive proximity of another rigid flat surface, undergoes spontaneous roughening with the formation of a short-wave isotropic structure.…”

Section: Introductionmentioning

confidence: 99%

“…This short-wave elastic contact instability, which involves no material transport by diffusion or convective flow, is quite distinct from the long-wave instability and dewetting of viscous liquid films because of the residual stresses, [11,12] van der Waals [1,2,7,14,17] or electric fields. [3][4][5][6]9,13] The length scale of the instability in liquid films depends strongly on the precise nature, magnitude and decay characteristic of the interactions and the wavenumber cut-off is solely controlled by the stabilizing influence of surface tension. In contrast, the wavelength (k) of adhesive field induced instability in a solid elastic films is largely independent of the nature and magnitude of the interaction forces and the surface tension.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Contact Instability of Elastic Bilayers: Miniaturization of Instability Patterns

Mukherjee

Pangule

Sharma

et al. 2007

Adv Funct Materials

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We show, both experimentally and theoretically, that the free surface of an elastic bilayer becomes spontaneously rough when brought in contact with another rigid surface. The lateral length scales of these self‐organized structures were found to scale as: λ = RF h, where h is the total bilayer thickness. The scale factor, RF could be modulated by the ratios of the individual film thicknesses and shear moduli. This is unlike the case of a single elastic film where the scale factor is independent of all material properties, RF ∼ 3. A linear stability analysis shows that the instability patterns in the bilayer can be tuned from the short waves (∼ 0.5 h) to long waves (∼ 8 h). Experiments show good agreement with the theoretical predictions regarding the existence of short wave deformations. Further, a rather catastrophic change in the wavelength from its minimum value, ∼h/2, to a limiting value of ∼ 3 h occurs by very small changes in the film thicknesses. This effect is explained by a switching of states in the bilayer energy curve which displays two minima at different wave numbers. Thus, the contact instability of elastic bilayers suggests novel strategies for the control of adhesion and engineering of feature sizes in a wide range. In particular, these findings have implications for further pattern miniaturization in the elastic contact lithography using pre‐patterned stamps.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Contact Instability of Elastic Bilayers: Miniaturization of Instability Patterns

Mukherjee

Pangule

Sharma

et al. 2007

Adv Funct Materials

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“…Recently, several soft-lithographic methods were devised that minimize the contact between the template and a liquid resist layer. [2][3][4][5][6] In these techniques a capillary film instability is directed towards the protrusions of a template facing a liquidpolymer film. The polymer is drawn towards these protrusions, thereby creating a positive replica of the template.…”

Section: Introductionmentioning

confidence: 99%

Electric‐Field‐Induced Pattern Morphologies in Thin Liquid Films

Voicu

Harkema

Steiner

2006

Adv Funct Materials

100

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Liquid‐polymer films sandwiched between two electrodes develop a surface instability caused by the electric field, giving rise to polymer structures that span the two plates. This study investigates the development of the resulting polymer morphologies as a function of time. The initial phase of the structure formation process is a sinusoidal surface undulation, irrespective of the sample parameters. The later stages of pattern formation depend on the relative amount of polymer in the capacitor gap (filling ratio). For high enough filling ratios, the final morphology of the pattern is determined by the partial coalescence of the initial pattern. The introduction of lateral‐field heterogeneities influences the initial pattern formation, with columns nucleated at locations of highest electric field (isolated points or edges). The subsequently formed secondary columns have higher degree of lateral symmetry compared to the pattern formed in a homogeneous field. The nucleation of individual columns or plugs also dominates the pattern formation in the presence of an electrode consisting of an array of lines. The results of this study therefore allow us to draw the conclusion that the accurate replication of structured electrodes typically proceeds by the initial nucleation of individual columns, followed by a coalescence process that yields the polymer replica.

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“…Several works on controlled self-organization during dewetting for engineering of nano-and micrometer patterns in thin liquid films have been reported. [17,20,21] In a recent work, in particular, we demonstrated a lithography technique for the fabrication of monochromatic organic light-emitting diode (OLED) pixel arrays, [14] in which organic materials are patterned with defined features by exploiting the instability phenomena affecting a liquid thin film on a nonwetting surface. [22] Such a method allows us to exploit the organizational capability of molecules, driven by external stimuli, to define well-resolved patterns on large-area substrates.…”

mentioning

confidence: 99%