The nanophase separation in diblock and triblock copolymers consisting of immiscible poly(n butyl acrylate) (block A) and gradient copolymers of methyl methacrylate (MMA) and n butyl acrylate (n BA) (block M/A) were investigated by means of their heat capacity, Cp, as a function of the composition of the blocks M/A and temperature. In all copolymers studied, both blocks are represented by their...

This note describes the application of nanoTA in the examination of a SAN/PC polyblend. The probe tip heats the sample locally at 25oC/sec while simultaneously monitoring the softening as the sample undergoes a glass transition Tg. Transition Temperature Microscopy is used to map mixing behavior and variations in phase composition originating at the nanoscale. Pure SAN and PC domains had latera...

The switching phenomenon observed in electronically conductive glasses corresponds to a sudden decrease in electrical resistance of the sample when a large electric field is applied. A simple electrothermal model is developed which takes into account only a Joule effect overheating of the material. In a temperature range below the glass transition temperature, Tg, the switching is reversible. O...

We use Monte Carlo simulations to study the static and dynamical properties of a Potts glass with infinite range Gaussian distributed exchange interactions for a broad range of temperature and system size up to N = 2560 spins. The results are compatible with a critical divergence of the relaxation time τ at the theoretically predicted dynamical transition temperature TD, τ ∝ (T−TD) −∆ with ∆ ≈ ...

The microscopic dynamics of several monomeric and polymeric glass-forming materials has been investigated by time-resolved fluorescence measurements of doped malachite green molecules in a wide temperature region. For monomers, 1-propanol, propylene glycol, and glycerol, and a polymer without side chains, polybutadiene, the temperature dependence of nonradiative decay time of doped malachite gr...

A simple, non-disordered spin model has been studied in an effort to understand the origin of the precipitous slowing down of dynamics observed in supercooled liquids approaching the glass transition. A combination of Monte Carlo simulations and exact calculations indicates that this model exhibits an entropy vanishing transition accompanied by a rapid divergence of time scales. Measurements of...

the glass transition temperature of several pvac(1)-b-poly(ma-co-mma) (2) terpolymers with different fractions of methyl acrylate (ma) and methyl methacrylate (mma) repeating units in random copolymer (block 2) were calculated with barton, kwei and topological equations. the calculation was on the basis of the correlation between the fraction of repeating units in random copolymers and theoreti...

The vitreous transition is characterized by a freezing of atomic degrees of freedom at a temperature Tg depending on the heating and cooling rates. A kinetic origin is generally attributed to this phenomenon instead of a thermodynamic one which we develop here. Completed homogeneous nucleation laws reflecting the energy saving due to Fermi energy equalization of nascent crystals and their melt ...

Dilute dipolar systems in three dimensions are expected to undergo a spin glass transition as the temperature decreases. Contrary to this, we find from Wang-Landau Monte Carlo simulations that at low concentrations x, dipoles randomly placed on a cubic lattice with dipolar interactions do not undergo a phase transition. We find that in the thermodynamic limit the “glass” transition temperature ...

Molecular dynamics (MD) simulation provides a unique window into the microscopic processes controlling the properties of amorphous silicates of geochemical importance. Of special interest are changes in structure and dynamics around the glass transition temperature. Seventeen simulations for composition CaAl2Si2O8 in a microcanonical ensemble of 1300 particles (O + Si + Al + Ca) were conducted ...