A Single Thermoresponsive Diblock Copolymer Can Form Spheres,Worms or Vesicles in Aqueous Solution

It is well‐known that the self‐assembly of AB diblock copolymers in solution can produce various morphologies depending on the relative volume fraction of each block. Recently, polymerization‐induced self‐assembly (PISA) has become widely recognized as a powerful platform technology for the rational design and efficient synthesis of a wide range of block copolymer nano‐objects. In this study, PISA is used to prepare a new thermoresponsive poly(N‐(2‐hydroxypropyl) methacrylamide)‐poly(2‐hydroxypropyl methacrylate) [PHPMAC‐PHPMA] diblock copolymer. Remarkably, TEM, rheology and SAXS studies indicate that a single copolymer composition can form well‐defined spheres (4 °C), worms (22 °C) or vesicles (50 °C) in aqueous solution. Given that the two monomer repeat units have almost identical chemical structures, this system is particularly well‐suited to theoretical analysis. Self‐consistent mean field theory suggests this rich self‐assembly behavior is the result of the greater degree of hydration of the PHPMA block at lower temperature, which is in agreement with variable temperature ¹H NMR studies.     

Temperature maps measurements on 3D surfaces with infrared thermography

The use of the infrared camera as a temperature transducer in wind tunnel applications is convenient and widespread. Nevertheless, the infrared data are available in the form of 2D images while the observed surfaces are often not planar and the reconstruction of temperature maps over them is a critical task. In this work, after recalling the principles of IR thermography, a methodology to rebuild temperature maps on the surfaces of 3D object is proposed. In particular, an optical calibration is applied to the IR camera by means of a novel target plate with control points. The proposed procedure takes also into account the directional emissivity by estimating the viewing angle. All the needed steps are described and analyzed. The advantages given by the proposed method are shown with an experiment in a hypersonic wind tunnel.     

The homogeneous Boltzmann hierarchy and statistical solutions to the homogeneous Boltzmann equation

An existence and uniqueness result for the homogeneous Boltzmann hierarchy is proven, by exploiting the statistical solutions to the homogeneous Boltzmann equation.     

Stationary Boltzmann equation for a degenerate gas in a slab: Boundary value problem and hydrodynamics

The boundary value problem for the stationary Boltzmann equation for a model gas in a plane slab is solved in full generality. The asymptotic behavior as the size of the slab goes to infinity is studied via a Chapman-Enskog expansion.     

Small deviations from local equilibrium for a process which exhibits hydrodynamical behavior. I

The symmetric simple exclusion process where infinitely many particles move randomly on , jump with equal probability on nearest-neighbor sites, and interact by simple exclusion is considered. It is known that the only extremal invariant measures are Bernoulli, that each measure, in a suitable class, after a macroscopic time is locally described, at a zero-order approximation, by a Bernoulli measure with parameter depending on macroscopic space and time, and that the so-defined equilibrium profile satisfies the heat equation. Small deviations from local equilibrium in the hydrodynamical limit are investigated. It is proven, under suitable assumptions, that at first order the state is Gibbs with one- and two-body potentials whose strength depends only on macroscopic space and time and on the equilibrium profile. More precisely, the one-body potential is linear (on the microscopic positions of the particles) and proportional to the macroscopic space gradient of the equilibrium parameter at that time, so that Fourier law holds. The two-body potential varies on a macroscopic scale and does not depend on the microscopic positions of the particles; it is given by the value of the covariance of the Gaussian macroscopic density fluctuation field.     

Stationary states for a mechanical system with stochastic boundary conditions

We consider a system of Newtonian particles, with a long-range repulsive pair potential, moving in a cavity whose surface temperature is spatially varying. When a particle hits the surface, it is thermalized at the temperature of the collision point. We prove that this system has a unique stationary ensemble, to which any initial distribution converges for large times. We show that this stationary ensemble depends continuously on the surface temperature profile.     

One‐pot,solvent‐free,metal‐free synthesis and UCST‐based purification of poly(ethylene oxide)/poly‐ε‐caprolactone block copolymers

A fast, one pot, solvent‐free and metal‐free synthesis of poly‐ε‐caprolactone and poly(ethylene oxide) block copolymers is reported. Copolymers with different molar mass, different hydrophilic to lipophilic balance, high degree of conversion and narrow molar mass dispersity have been obtained by organocatalyzed ring opening polymerization of ε‐caprolactone in presence of mono‐ or diol‐poly(ethylene oxide) as initiator and fumaric acid as catalyst. A new biocompatible and environmental friendly purification method is presented, exploiting the upper critical solution temperature of these class of copolymers in ethanol. The phase diagrams of the synthesized copolymers in ethanol are also reported. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2992–2999     

The trend to a stationary state for the Lebowitz Stick model

The asymptotic behaviour of the Lebowitz stick model in kinetic theory is studied in weak* measure, L¹- and L^∞-sense.