Stability Analysis of Catenoidal Shaped Liquid Crystalline Polymer Networks

Rey, Alejandro D.

doi:10.1021/ma9705331

Cited by 3 publications

(5 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…LC molecules in the channel flow from the thinnest center toward the thickest ends of the channels and then orient along the flow direction. The driving force for the flow is the capillary pressure between the thinnest center and the thickest ends of the channels. ,5i,, Because of this flow, the channels become thinner and thinner; finally, it breaks up at a critical diameter of about 1 μm,5i resulting in an increase in network size and spacing. To further lower the interface free energy of the system, the broken-up arms will shrink and reshape into smoother network.…”

Section: Discussionsupporting

confidence: 80%

Phase Separation Dynamics and Pattern Formation in Thin Films of a Liquid Crystalline Copolyester in Its Biphasic Region

2003

View full text Add to dashboard Cite

We present the experimental results concerning a phase separation dynamics and relevant pattern formation in thin film samples (ca. 10 µm in thickness) of a liquid crystalline copolyester in its biphasic region. The copolyester separates into an isotropic phase and an anisotropic phase in the biphasic region due to its composition heterogeneity, though it is homopolymer. The entire phase-separation process was in situ monitored in real space by polarized light microscopy. The structural evolution that appeared in the digital images was further analyzed using the fast Fourier transform method. The process can be described by the following steps: (1) The formation of a percolated network consisting of phase-separated isotropic and anisotropic liquids. The network growth obeys a scaling law Λ m(t) ∝ qm(t) -1 ∝ t R , where Λm(t) is the characteristic length of the domains, qm(t) is the characteristic wavenumber, and t is the time. A crossover of the exponent from 1 /3 to 1 /2 was observed. (2) The network breaks up at a critical value of Λm(t) ) 50 µm to form some anisotropic fragments with irregular shapes, followed by the further shrinking and reshaping into anisotropic drops. (3) The diffusion-coalescence of the drops to form large merged drops and the reshaping of these merged drops followed by orientational ordering within the merged drops. We studied the temperature dependence of these individual processes and discussed the mechanisms and the scaling behavior of the domain growth in the first step.

show abstract

Section: Discussionsupporting

confidence: 80%

Phase Separation Dynamics and Pattern Formation in Thin Films of a Liquid Crystalline Copolyester in Its Biphasic Region

2003

View full text Add to dashboard Cite

show abstract

“…Water minimizes its surface free energy by adopting this shape (36). Viscous flow inside the catenoid creates fluid movement both up and down from the thinnest toward the thickest section of the channel (37). Coalescence thins out the inner channel ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Versatile solution for growing thin films of conducting polymers

D’Arcy

Tran²,

Tung³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The method employed for depositing nanostructures of conducting polymers dictates potential uses in a variety of applications such as organic solar cells, light-emitting diodes, electrochromics, and sensors. A simple and scalable film fabrication technique that allows reproducible control of thickness, and morphological homogeneity at the nanoscale, is an attractive option for industrial applications. Here we demonstrate that under the proper conditions of volume, doping, and polymer concentration, films consisting of monolayers of conducting polymer nanofibers such as polyaniline, polythiophene, and poly(3-hexylthiophene) can be produced in a matter of seconds. A thermodynamically driven solution-based process leads to the growth of transparent thin films of interfacially adsorbed nanofibers. High quality transparent thin films are deposited at ambient conditions on virtually any substrate. This inexpensive process uses solutions that are recyclable and affords a new technique in the field of conducting polymers for coating large substrate areas.Marangoni | surface tension | thin film technology | organic electronics C onducting polymers hold promise as flexible, inexpensive materials for use in electronic applications including solar cells, light-emitting diodes, and chemiresistor-type sensors (1-3). Whereas traditional nonconjugated polymers are often solutionprocessable, many organic conducting polymers have been notoriously difficult to process into films. Thin films of conducting polymers offer a large ratio of charge carriers to volume of active layer (4) and can achieve high field-effect mobilities as a result of low-dimensional transport (5). Therefore a simple, scalable, cost-effective deposition technique for conducting polymers that produces a uniform thin film morphology reproducibly is needed.Film-forming methods for conducting polymers on the basis of solution processing, electrochemistry, and thermal annealing have been reported in the literature but suffer from a variety of problems. The conducting polymers polyaniline (PANi), polythiophene, and their derivatives such as poly(3-hexylthiophene) (P3HT) are commonly processed into nanoscale thin films via spin coating (1, 5-7) for applications in organic photovoltaics, thin film transistors, and electrochromic devices (8-12). However, spin coating is a technique that suffers from a low material utilization yield and is therefore not cost-effective (11), a fact that hinders its potential for scale-up. Another well known deposition strategy is the electrochemical growth of conducting polymer thin films via galvanostatic, potentiostatic, or voltammetric routes (9,(13)(14)(15)). An inherent limitation of using electricity for thin film deposition is the dual role played by the electrode/substrate, which excludes the possibility of film deposition on a nonconducting substrate. This problem also applies to electrospraying because it requires a high voltage across electrodes (11). Other solution-based methods also present challenges; for example, the Lang...

show abstract

“…Equation ( 5) represents the second variation of area A with respect to the horizontal displacement of the bottom ring, assuming that the surface S continuously satisfies the minimal property (10). Its right hand side ( 5) is positive for all H as evidenced by the plot in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The interior condition on C is obtained by applying the δ/δt-derivative to equation (10), which results in the differential equation…”

Section: Calculation Of Cmentioning

confidence: 99%

See 1 more Smart Citation

In-plane Oscillations of a Ring Driven by a Soap Film Catenoid

Grinfeld¹

2012

View full text Add to dashboard Cite

In this paper, we calculate the frequency of small oscillations of a ring confined to a plane that, along with a fixed ring of the same size, supports a soap film catenoid. The restoring force is provided by the film's surface tension. We assume that the soap film is massless and continuously assumes the shape of minimal area. Mathematically, the problem is equivalent to calculating the second derivative of the total area with respect to the displacement of the ring. The calculus of moving surfaces is extensively used in the presented calculation.

show abstract

Stability Analysis of Catenoidal Shaped Liquid Crystalline Polymer Networks

Cited by 3 publications

References 9 publications

Phase Separation Dynamics and Pattern Formation in Thin Films of a Liquid Crystalline Copolyester in Its Biphasic Region

Phase Separation Dynamics and Pattern Formation in Thin Films of a Liquid Crystalline Copolyester in Its Biphasic Region

Versatile solution for growing thin films of conducting polymers

In-plane Oscillations of a Ring Driven by a Soap Film Catenoid

Contact Info

Product

Resources

About