The drying of nanocolloidal polymers is governed by the interplay among surface tension, evaporation, and contact-line pinning, among other phenomena. Here, we describe the sequential evolution of poly-3,4-ethylenedioxythiophene:poly(styrene sulfonate) (PEDOT:PSS) through two distinct regimes evidenced by annular or radial cracking and show that the cracking dynamics and solvent-retention postdrying and postcracking are mediated by wetting to the substrate surface. The corresponding changes in the PEDOT:PSS morphology are also observed to relate to the radial or cracking dynamics. It is suggested that the wetting-dependent effect offers a route to control morphology, understand solvent retention, and reduce cracking in polymer latex films. Sportsfest program examples. This study highlights the importance of substrate choice, an underexplored area of investigation in the study of colloidal materials.
Cracking phenomena are observed in practically every colloidal solid, from the largest mudflats to small blood traces in medical diagnosis to the almost-microscopic trails deposited in inkjet printing. Most interest in cracking behavior aims to eliminate cracks to improve electrical, optical, or other material performance, but the same dynamics can also be harnessed as a tool for self-assembly, for example, toward large-area transparent conductive nanostructures. This study describes crack patterns observed in dropcast poly-3,4-ethylenedioxythiophene:poly(styrene sulfonate) (PEDOT:PSS) toward improved lab-to-lab repeatability and predictive control of the complex polymer dynamics. The aim of this study is to provide a cogent description of the trends to mediate the surface dynamics and point to morphological issues related to surface wetting. We intend to advance specific understanding of this conducting polymer and to contribute to the study of colloidal drying in general.
PSS 21H-4N1 B3 I/A Series® Process NMR Analyzer Model NMRB, Style C INTRODUCTION The Foxboro Process NMR (nuclear magnetic. Naphtha Cracking FCCU Feed. Pss E, free pss e software downloads, Page 3. Nov 12, 2014 Hi all, I need to learn PSS®E University 32 for electrical simulation result. Please tell from where.
There are several useful properties of PEDOT:PSS, including high electrical conductivity, good optical transparency, mechanical flexibility, and coating stability over time. Moreover, because PEDOT:PSS films simultaneously exhibit high electrical conductivity and low thermal conductivity, progress is being made in the application of PEDOT:PSS as a thermoelectric material. Cracking behavior compromises these useful properties. Internal stresses built up during the drying process also reduce material performance, even if cracking does not occur. This study examines the accumulation of tensile and compressive stresses at different points in the drying process, mediated by the contact angle with the substrate. Specific cracking and deposition phenomena have been identified in drying colloids.
Research continues to investigate both basic drying mechanisms and the effects the drying process has on the properties of the resulting film. One of the most intensively studied is the coffee-ring effect, in which solids are deposited in a ring when the contact line between the droplet and the substrate is pinned. As a result of this pinning, liquid flows toward the outer edge of the droplet to replace the liquid lost through evaporation, carrying with it the suspended particles. Colloids have been found to dry in a four-stage process, with flow effects like those mentioned above dominating in the “submerged phase”. During the “wet” and “moist” phases, after the liquid has receded below the level of the solid material surface, drying behavior is largely determined by capillary forces on the solid–liquid interfaces. In this paper, we clearly observe the existence of the submerged and wet phases in a drying colloid.
We characterize the cracks that form in each phase both on the centimeter scale and by scanning electron microscopy (SEM). One important type of colloid is the latex (plural: lattices), defined as an aqueous colloidal dispersion of polymer particles. It is a conductive polymer latex that is studied in this paper. Lattices have a number of advantages compared to other polymer forms for industrial applications: they can be processed at room temperature and using a variety of inexpensive processes, including inkjet printing, silkscreening, and spin-coating. Using aqueous dispersions also avoids the safety and health issues associated with volatile organic solvents. Many different polymers can be produced in latex form by emulsion polymerization. Nanoparticle lattices are particularly exciting because they allow for nanomaterial self-assembly, using simple bottom-up processes.