28 research outputs found
Topological phase transition in a RNA model in the de Gennes regime
We study a simplified model of the RNA molecule proposed by G. Vernizzi, H.
Orland and A. Zee in the regime of strong concentration of positive ions in
solution. The model considers a flexible chain of equal bases that can pairwise
interact with any other one along the chain, while preserving the property of
saturation of the interactions. In the regime considered, we observe the
emergence of a critical temperature T_c separating two phases that can be
characterized by the topology of the predominant configurations: in the large
temperature regime, the dominant configurations of the molecule have very large
genera (of the order of the size of the molecule), corresponding to a complex
topology, whereas in the opposite regime of low temperatures, the dominant
configurations are simple and have the topology of a sphere. We determine that
this topological phase transition is of first order and provide an analytic
expression for T_c. The regime studied for this model exhibits analogies with
that for the dense polymer systems studied by de GennesComment: 15 pages, 4 figure
Nucleation and crystallization in bio-based immiscible polyester blends
Bio-based thermoplastic polyesters are highly promising materials as they combine interesting thermal and physical properties and in many cases biodegradability. However, sometimes the best property balance can only be achieved by blending in order to improve barrier properties, biodegradability or mechanical properties. Nucleation, crystallization and morphology are key factors that can dominate all these properties in crystallizable biobased polyesters. Therefore, their understanding, prediction and tailoring is essential. In this work, after a brief introduction about immiscible polymer blends, we summarize the crystallization behavior of the most important bio-based (and immiscible) polyester blends, considering examples of double-crystalline components. Even though in some specific blends (e.g., polylactide/polycaprolactone) many efforts have been made to understand the influence of blending on the nucleation, crystallization and morphology of the parent components, there are still many points that have yet to be understood. In the case of other immiscible polyester blends systems, the literature is scarce, opening up opportunities in this environmentally important research topic.The authors would like to acknowledge funding by the BIODEST project ((RISE) H2020-MSCA-RISE-2017-778092
Synthesis and characterization of an antibacterial powder based on the covalent bonding of aminosilane-stabilized silver nanoparticles to a colloidal silica
Optical properties of films of polycarbazolyldiacetylene PDCHD-HS for photonic applications
none10GIORGETTI E.;MARGHERI G.; GELLI F.; SOTTINI S.; COMORETTO D.; CRAVINO A.; CUNIBERTI C.; DELL'ERBA C.; MOGGIO I.; DELLEPIANE G.Giorgetti, E.; Margheri, G.; Gelli, F.; Sottini, S.; Comoretto, Davide; Cravino, A.; Cuniberti, CARLA EMILIA; Dell'Erba, Carlo; Moggio, I.; Dellepiane, Giovann
Epoxy networks modified by multifunctional polyhedral oligomeric silsesquioxanes (POSS) containing amine groups
Epoxy Networks with Physical Cross-Links Produced by Tail-to-Tail Associations of Alkyl Chains
Influence of Precursor Concentration on the Formation of Silver Nanoparticles with Oligostyrylmonocarboxylate Ligands in ED-20 Epoxy Oligomer
Position-based dynamic of a particle system: a configurable algorithm to describe complex behaviour of continuum material starting from swarm robotics
International audienceIn a previous work, we considered a two-dimensional lattice of particles and calculated its time evolution by using an interaction law based on the spatial position of the particles themselves. The model reproduced the behaviour of deformable bodies both according to the standard Cauchy model and second gradient theory; this success led us to use this method in more complex cases. This work is intended as the natural evolution of the previous one in which we shall consider both energy aspects, coherence with the principle of Saint Venant and we start to manage a more general tool that can be adapted to different physical phenomena, supporting complex effects like lateral contraction, anisotropy or elastoplasticit