Melting of crystals is an archetypical first order phase transition. Albeit extensive efforts, the molecular origin of this process in polymers is still not clear. Experiments are complicated by the tremendous change in mechanical properties and the occurrence of parasitic phenomena masking the genuine material response. Here, we present an experimental procedure permitting to circumvent these issues by investigating the dielectric response of thin polymer films. Extensive measurements on several commercially available semicrystalline polymers allowed us to identify a genuine molecular process associated with the newly formed liquid phase. In line with recent observations of amorphous polymer melts, we show this mechanism�known as the slow Arrhenius process (SAP)�involves time scales longer than those characteristics of segmental mobility and has the same energy barrier of the flow of the melt.

<div><div><div><p>Electrically conducting nanospheres of poly-(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) with tailored size, were prepared by a one-step method. To fabricate the nanostructures, PEDOT:PSS was dissolved in ethylene glycol using a novel strategy and the solution was precipitated in deionized water. The proposed fabrication route allowed to obtain a water-based dispersion of monodisperse nanospheres with good optical properties. To determine physical properties of the nanospheres, we followed a nanoscale approach, using Atomic Force Microscopy (AFM). Our nanoscale mechanical and electrical investigations showed that the nanospheres preserved good physical properties, compared to the commercial product. Moreover, the local studies indicated that the confinement imposed by the spherical shape can lead into a different arrangement of the PSS and PEDOT phases. In particular, we envisaged nanospheres composed by a PEDOT-rich surface, responsible for the good electrical conductivity of the nanostructures.</p></div></div></div>

No abstract

<div><div><div><p>Electrically conducting nanospheres of poly-(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) with tailored size, were prepared by a one-step method. To fabricate the nanostructures, PEDOT:PSS was dissolved in ethylene glycol using a novel strategy and the solution was precipitated in deionized water. The proposed fabrication route allowed to obtain a water-based dispersion of monodisperse nanospheres with good optical properties. To determine physical properties of the nanospheres, we followed a nanoscale approach, using Atomic Force Microscopy (AFM). Our nanoscale mechanical and electrical investigations showed that the nanospheres preserved good physical properties, compared to the commercial product. Moreover, the local studies indicated that the confinement imposed by the spherical shape can lead into a different arrangement of the PSS and PEDOT phases. In particular, we envisaged nanospheres composed by a PEDOT-rich surface, responsible for the good electrical conductivity of the nanostructures.</p></div></div></div>

No abstract

We present the preparation of nanostructured conducting PEDOT:PSS thin films by solvent vapor annealing (SVA), using the low boiling point solvent tetrahydrofuran (THF). An Atomic Force Microscopy (AFM) study allowed the observation of distinct nanostructure development as a function of solvent exposure time. Moreover, the nanostructures’ physical properties were evaluated by nanomechanical, nanoelectrical, and nano-FTIR measurements. In this way, we were able to differentiate the local response of the developed phases and to identify their chemical nature. The combination of these techniques allowed to demonstrate that exposure to THF is a facile method to effectively and selectively modify the surface nanostructure of PEDOT:PSS, and thereafter its final properties. Moreover, our nanoscale studies provided evidence about the molecular rearrangements that PEDOT:PSS suffers during nanostructure fabrication, a fundamental fact in order to expand the potential applications of this polymer in thermoelectric and optoelectronic devices.

Electrically conducting nanospheres of poly-(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) with tailored size were prepared by a solvent displacement technique. To fabricate the nanostructures, dried PEDOT:PSS was dissolved in ethylene glycol (EG) and the solution was precipitated in deionized water. The proposed fabrication route allowed to obtain a water-based dispersion of PEDOT:PSS nanospheres with good optical properties. To determine the physical properties of the nanospheres, we followed a nanoscale approach, using Atomic Force Microscopy. Our nanoscale mechanical and electrical investigations showed that the nanospheres preserved good physical properties, compared to the commercial product. Moreover, the local studies indicated that the confinement imposed by the spherical shape and the treatment with EG lead to a different arrangement of the PSS and PEDOT phases, responsible for the good electrical conductivity of the nanostructures.

No abstract