Raffaele Pastore, Ph.D.

Assistant Professor (RTD-B)
Università degli Studi di Napoli Federico II

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News and Highlights

Breakdown of the Stokes-Einstein relation in supercooled liquids:
a cage-jump perspective

R. Pastore, T. Kikutsuji, F. Rusciano, N. Matubayasi, K. Kim and F.Greco
just published in The Journal of Chemical Physics.

Congrats to Takuma Kikutsuji from Osaka University, for the
major contribution to this paper, while he was visiting scholar in our lab

Download the accepted manuscript

Homeostatic swimming of zooplankton upon crowding:
the case of the copepod Centropages typicus

in collaboration with Lund University, University of Wisconsin–Milwaukee and Stazione Zoologica Dohrn
just published in the Journal of the Royal Society Interface

Download the accepted manuscript

New paper in collaboration with MIT and Univ. Messina
Tailoring Chitosan/LTA Zeolite Hybrid Aerogels for Anionic and Cationic Dye Adsorption
M. Salzano de Luna, F. Greco, R. Pastore, G. Mensitieri, G. Filippone, P. Aprea, D. Mallamace, F. Mallamace and S.-H. Chen,
published in International Journal of Molecular Sciences

We are organizing an on-line course on
"Advances in Functional Materials:
Fundamentals, Technology and Sustainable Energy Production"

to be held on 6th and 7th July in the framework of the Ettore Majorana Foundation (Erice, Italy)
Have a look at the Course dedicated Website .

Now published in PRL
Rapid Fickian Yet Non-Gaussian Diffusion after Subdiffusion

R. Pastore, A. Ciarlo, G. Pesce, F. Greco, and A. Sasso
Physical Review Letters 126, 158003 (2021)

Download the article PDF

New paper in collaboration with P&G Brussels
Understanding charged vesicle suspensions as Wigner glasses: dynamical aspects
Giuseppe Porpora, Francesco Rusciano, Vincenzo Guida, Francesco Greco and Raffaele Pastore
just accepted in Journal of Physics: Condensed Matter

Happy and proud to be a guest editor of the special issue
Glasses and gels: a crossroad of
molecular liquids, polymers and colloids

just announced in Journal of Physics: Condensed Matter, with a spectacular list of outstanding invited contributions

Alginate gels, Anomalous aging and Rheology,
Ultra-long dynamic correlations, Stretched/Compressed relaxation
in our last paper in Macromolecules

Anomalous Aging and Stress Relaxation in
Macromolecular Physical Gels: The Case of Strontium Alginate

R. Pastore, C. Siviello, F. Greco, and D. Larobina

New paper in collaboration with Agenzia Spaziale Italiana
Linestrength ratio spectroscopy as a new primary thermometer
for redefined Kelvin dissemination

L. Santamaria Amato, M. Siciliani de Cumis1, G. Bianco, R. Pastore and Pablo Cancio Pastor
published in New Journal of Physics

Talk at Polychar 27
"Influence of wall heterogeneity on polymer nano-sandwiches:
a multiscale analysis"

Joint Talk with Dr. Marco Uttieri at Meeting BioPhys and PlexNet 2019
"Impact of different environmental conditions on
the swimming strategies of planktonic copepods"

We are organizing a course at Ettore Majorana Foundation
"Polymers and Soft Materials: Glasses, Gels and Networks"
Erice, 9 – 16 July 2019
Have a look at the Flyer and at the course Website .
Interested students should contact me asap!

Concentrated suspensions of Brownian beads in water:
dynamic heterogeneities trough a simple experimental technique

R. Pastore, M. Caggioni, D. Larobina, L. Santamaria Amato and F. Greco

just accepted
in the Special Topic on Water Science of
SCIENCE CHINA Physics, Mechanics & Astronomy

Our paper just accepted in PCCP
Influence of wall heterogeneity on nanoscopically confined polymers
R. Pastore, A. David, M. Casalegno, F. Greco and G. Raos


I was pleased to participate in the Erice summer-school "Water and water systems: the hydrophobic effect" and give a lecture on
"Intermittent and heterogeneous dynamics in soft glassy materials".

Have a look at the slides.

Awarded Best young researcher article prize 2017 by CNR-SPIN
for my paper
Cage Size and Jump Precursors in Glass-Forming Liquids

Our paper in collaboration with researchers at
Stazione Zoologica A. Dohrn and Lund University,
Distinctive diffusive properties of swimming planktonic
copepods in different environmental conditions

R. Pastore, M. Uttieri, G. Bianco, M. Ribera d'Alcalá and M. G. Mazzocchi

now in BiorXiv

Talk in Primosten (Croatia)
EUSMI/SoftComp Annual Meeting 2018
"Intermittent and heterogeneous dynamics in soft glassy materials: experiment and simulations"

Talk in Sorrento at AERC2018
Annual European Rheology Conference
"Dense vesicle suspensions: relaxation processes and dynamic heterogeneities"

Talk in Lisbon (Portugal)
Flowing Matter 2018 (organized by Cost Action MP1305)
"Cage Size and Jump Precursors in Glass-Forming Liquids: Experiment and Simulations"

Effects of Chemically Heterogeneous Nanoparticles on Polymer Dynamics: Insights from Molecular Dynamics Simulations
Zijian Zheng, Fanzhu Li, Jun Liu, Raffaele Pastore, Guido Raos, Youping Wu and Liqun Zhang

just accepted in Soft Matter

I just joined DICMaPI at the University of Naples Federico II as Assistant Professor (RTD-A)

Visiting Scientist at
Dip. di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano
and at
Dip. di Biotecnologie Mediche e Medicina Traslazionale, Università di Milano

Our paper on organic photovoltaic is in the JPCC most read article list

AudioSlides are now available online. Have a look!

Our paper on organic solar cells is finally out!
Origin of Charge Separation at Organic Photovoltaic Heterojunctions:
A Mesoscale Quantum Mechanical View

M. Casalegno, R. Pastore, J. Idé, R. Po and G. Raos

open access in The Journal of Physical Chemistry C

Many facets of intermittent dynamics in colloidal and molecular glasses
R. Pastore, G. Pesce, A. Sasso and M. Pica Ciamarra

just accepted in Colloids and Surfaces A

“Endocyticic reawakening of motility and flocking in jammed epithelia”
by my guest Prof. Roberto Cerbino (University of Milan)

Talk in Napoli
Fluids and Structures: Interaction and Modeling (organized by Cost Action MP1305)
" Structural relaxation and dynamic heterogeneities in soft materials: a simple experimental approach"

Press relase on DVA by the University of Cincinnati

We are happy to announce the press release on DVA by CNR

Read this news in "Le Scienze"

Read the english version of the press release

"Criticality and avalanches at the yelding transition of amorphous solids under deformation"
by my guest Dr. Ezequiel Ferrero (University of Milan)

Read Abstract

News on DVA in the University of Naples web-site (in Italian)

Cage Size and Jump Precursors in Glass-Forming Liquids: Experiment and Simulations
R. Pastore, G. Pesce, A. Sasso and M. Pica Ciamarra

just accepted in The Journal of Physical Chemistry Letters

Differential Variance Analysis: a direct method to quantify and visualize dynamic heterogeneities
R. Pastore, G. Pesce and M. Caggioni

just published in Nature Scientific Reports
DVA dedicated page

Relaxation functions and dynamical heterogeneities in a model of chemical gel interfering with glass transition
A. de Candia, A. Fierro, R. Pastore, M. Pica Ciamarra and A. Coniglio

just accepted in EPJ ST
Freely available view-only version

Invited talk at Ph.D. Complex Fluids School@Unina
organized by University of Naples Federico II and P&G
"Dynamic heterogeneities in complex fluids: a simple experimental approach"

Talk in Rome at the
30th Conference of the European Colloid and Interface Society
(ECIS), Rome, Sept 4-9, 2016

"Many facets of intermittent dynamics in colloidal and molecular glasses"

Cluster structure and dynamics in gels and glasses
R. Pastore, A. de Candia, A. Fierro, M. Pica Ciamarra and A. Coniglio

just published in JSTAT (arXiv preprint)

Talk at Harvard University
90th ACS Colloid & Surface Science Symposium, June 5-8, 2016
"Many facets of intermittent dynamics in colloidal and molecular glasses"

Charge separation and charge transport in hybrid solar cells
PI: R. Pastore
Report Abstract

We are investigating electronic properties of organic/hybrid heterojunctions for photovoltaic applications. In collaboration with the Raos group (Politecnico di Milano), who introduced a novel quantum chemical model (JCTC 2013), we show that this method is able to simulate systems much larger than allowed by any other quantum chemical approach (see Fig.). This leads to investigate the charge delocalization and the exciton separation over the full length-scale relevant to these processes. In addition, we are performing Monte Carlo and Molecular Dynamics simulations to investigate how the morphological and dynamical properties of the active layer affect the macroscopic charge transport.

Cage-jump motion reveals universal dynamics and non-universal
structural features in glass forming liquids

R. Pastore, A. Coniglio, A. de Candia, A. Fierro and M. Pica Ciamarra

just accepted in JSTAT (arXiv preprint)

February-August 2016
visiting @ University of Cincinnati and Procter&Gamble Co.

Review article
Particle jumps in structural glasses
M. Pica Ciamarra, R. Pastore and A. Coniglio

Soft Matter (2015), DOI: 10.1039/C5SM01568E .

Particles in structural glasses rattle around temporary equilibrium positions, that seldom change through a process which is much faster than the relaxation time, known as particle jump. Since the relaxation of the system is due to the accumulation of many such jumps, it could be possible to connect the single particle short time motion to the macroscopic relaxation by understanding the features of the jump dynamics. Here we review recent results in this research direction, clarifying the features of particle jumps that have been understood and those that are still under investigation, and examining the role of particle jumps in different theories of the glass transition.

October 2015
visiting @ NTU Singapore

Glassy dynamics of a polymer monolayer on a
heterogeneous disordered substrate

R. Pastore and G. Raos

Soft Matter (2015), DOI: 10.1039/C5SM01440A (Open Access).

We present molecular dynamics simulations of a polymer monolayer on randomly functionalized surfaces that are characterized by different fractions of weakly and strongly attractive sites. We show that the dynamics slow-down upon cooling resembles that of a strong glass-forming liquid. Indeed, the mean-square displacements show an increasingly lasting subdiffusive behaviour before the diffusive regime, with signs of Fickian yet not Gaussian diffusion, and the dynamic correlation functions exhibit a stretched exponential decay. The glassy dynamics of this relatively dilute system is dominated by the interaction of the polymer with the substrate and becomes more marked when the substrate composition is heterogeneous. Accordingly, the estimated glass transition temperature shows a non-monotic dependence on surface composition, in agreement with previous results for the activation energy and with an analysis of the potential energy landscape experienced by the polymer beads. Our findings are relevant to the description of polymer-surface adhesion and friction and the development of polymer nanocomposites with tailored structural and mechanical properties.

Spatial correlations of elementary relaxation
events in glass-forming liquids

R. Pastore, A. Coniglio, and M. Pica Ciamarra

Soft Matter (2015), DOI: 10.1039/C5SM01510C .

The dynamical facilitation scenario, by which localized relaxation events promote nearby relaxation events in an avalanche process, has been suggested as the key mechanism connecting the microscopic and the macroscopic dynamics of structural glasses. Here we investigate the statistical features of this process via numerical simulations of a model structural glass. First we show that the relaxation dynamics of the system occurs through particle jumps that are irreversible, and that cannot be decomposed in smaller irreversible events. Then we show that each jump does actually trigger an avalanche. The characteristics of this avalanche change upon cooling, suggesting that the relaxation dynamics crossovers from a noise dominated regime, where jumps do not trigger other relaxation events, to a regime dominated by the facilitation process, where a jump triggers more relaxation events.

CECAM Workshop: The Role of Structure in Dynamical Arrest
Mainz (Germany)
My Talk


Scientific Reports 5, 11770 (2015)

"Quantum chemical models of organic photovoltaic
materials for relatively large systems"
Prof. Guido Raos (Politecnico di Milano)
Read Abstract

"On the nature of the glass crossover"
Dr. Tommaso Rizzo (CNR-ISC, Roma)
Read Abstract

XIV International Workshop on Complex Systems
Fai della Paganella (Italy)
My Talk

Dynamical phase coexistence in glass-forming liquids
R. Pastore, A. Coniglio, and M. Pica Ciamarra

One of the most controversial hypotheses for explaining the heterogeneous dynamics of molecular and colloidal glasses postulates the temporary coexistence of two phases, characterized by a high and by a low value of the diffusion coefficient. In this scenario, two phases with different diffusivities coexist for a time of the order of the relaxation time, and mix afterwards. Unfortunately, it is difficult to measure the single particle diffusion coefficient to test this hypothesis. Indeed, although the not-Gaussian shape of the van Hove distribution suggests the transient existence of a distribution of diffusion coefficients, it is not possible to infer from this quantity whereas two or more dynamical phases coexist. Here we provide the first direct observation of the dynamical coexistence of two phases with different diffusion coefficients, by showing that in the deeply supercooled regime the distribution of the single particle diffusion coefficients acquires a transient bimodal shape. We relate this distribution to the heterogeneity of the dynamics and to the breakdown of the Stokes-Einstein relation. Our work offers a basis for rationalizing the dynamics of supercooled liquids, and for relating their structural and dynamical properties.
ArXiv:1412.5304 .

Connecting short and long time dynamics
in hard-sphere-like colloidal glasses

R. Pastore, M. Pica Ciamarra, G. Pesce and A. Sasso

Soft Matter 11, 622 (2015)

Glass-forming materials are characterized by an intermittent motion at the microscopic scale. Particles spend most of their time rattling within the cages formed by their neighbors, and seldom jump to a different cage. In molecular glass formers the temperature dependence of jump features, such as the average caging time and the typical jump length, characterize the relaxation processes and allow for a short-time prediction of the diffusivity. Here we experimentally investigate the cage-jump motion of a two-dimensional hard-sphere-like colloidal suspension, where the volume fraction is the relevant parameter controlling the slow down of the dynamics. We characterize the volume fraction dependence of the cage-jump features and show that, as in molecular system, they allow for a short time prediction of the diffusivity.
Soft Matter 11, 622 (2015)

Awarded SEED 2014 Grant

Charge separation and charge transport in hybrid solar cells

PI: Raffaele Pastore.

Co-Investigators: Dr. A. Bruno (ENEA); Dr. G. Cantele (CNR-SPIN); Prof. D. Ninno (U. of Naples); Dr. A. de Candia (U. of Naples); Dr. A. Fierro (CNR-SPIN); Dr. G. De Filippis (U. of Naples); Prof. M. Pica Ciamarra (Nanyang Technological University, Singapore).

Experiments on hard-sphere-like colloidal glasses

We connect the intermittent single particle motion and the macroscopic dynamics in colloidal suspensions at increasing volume fraction.
(With M. Pica Ciamarra, G. Pesce and A. Sasso)

From cage-jump motion to macroscopic diffusion
in supercooled liquids

R. Pastore, A. Coniglio, and M. Pica Ciamarra

Soft Matter 10, 5724 (2014) .

The evaluation of the long term stability of a material requires the estimation of its long-time dynamics. For amorphous materials such as structural glasses, it has proven difficult to predict the long-time dynamics starting from static measurements. Here we consider how long one needs to monitor the dynamics of a structural glass to predict its long-time features. We present a detailed characterization of the statistical features of the single-particle intermittent motion of structural glasses, and show that single- particle jumps are the irreversible events leading to the relaxation of the system. This allows to evaluate the diffusion constant on the time-scale of the jump duration, which is small and temperature independent, i.e. well before the system enters the diffusive regime. The prediction is obtained by analyzing the particle trajectories via a parameter-free algorithm.

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