相关论文: Glass Transition Temperature and Dynamics of $\alp…
The glass transition temperature $T_{\rm g}$ and the temperature $T_{\alpha}$ corresponding to the peak in the dielectric loss due to the $\alpha$-process have been simultaneously determined as functions of film thickness d through…
Dielectric relaxation and thermal expansion spectroscopy were made for thin polystyrene films in order to measure the temperature $T_{\alpha}$ corresponding to the peak in the loss component of susceptibility due to the $\alpha$-process and…
The $\alpha$-process (segmental motion) of thin polystyrene films supported on glass substrate has been investigated in a wider frequency range from 10$^{-3}$ Hz to 10$^4$ Hz using dielectric relaxation spectroscopy and thermal expansion…
Dynamics of thin films of poly(vinyl acetate) (PVAc) and poly(methyl methacrylate) (PMMA) have been investigated by dielectric relaxation spectroscopy in the frequency range from 0.1Hz to 1MHz at temperatures from 263K to 423K. The…
Glass transition process gets affected in ultrathin films having thickness comparable to the size of the molecules. We observe systematic broadening of glass transition temperature (Tg) as the thickness of the polymer film reduces below the…
Recent experiments have demonstrated that the glass transition temperature of thin polymer films can be shifted as compared to the same polymer in the bulk, the amplitude and the sign of this effect depending on the interaction between the…
The glass transition temperature ($T_g$) of polymer thin films has been a subject of controversy in the last two decades. (Pseudo)thermodynamic determinations of $T_g$ generally suggest a significant depression, whereas the molecular…
The glass transition temperature and its connection to statistical properties of confined and free-standing polymer films of varying thickness containing unentangled to highly entangled bead-spring chains are studied by molecular dynamics…
We investigate the relaxation behavior of thin films of a polyamide random copolymer, PA66/6I, with various film thicknesses using dielectric relaxation spectroscopy. Two dielectric signals are observed at high temperatures, the…
Latest since the landmark studies of Kovacs and co-workers on the glass transition of polymers, it is clear that thermally induced volume changes are of central importance for the understanding of the nature of the glass transition. Due to…
A simple and predictive model is put forward explaining the experimentally observed substantial shift of the glass transition temperature, Tg, of sufficiently thin polymer films. It focuses on the limit of small molecular weight, where…
The glass transition temperature and relaxation dynamics of the segmental motions of thin films of polystyrene labeled with a dye, 4-[N-ethyl-N-(hydroxyethyl)]amino-4-nitraozobenzene (Disperse Red 1, DR1) are investigated using dielectric…
We have investigated the reduction of the glass transition temperature, $T_g$, for thin supported films of particularly small molecular weight ($M_W$ = 2 kg/mol) polystyrene, and found good agreement with earlier studies on larger…
Glass transition temperature ($T_{\text{g}}$) plays an important role in controlling the mechanical and thermal properties of a polymer. Polyimides are an important category of polymers with wide applications because of their superior heat…
In an earlier preprint (V. V. Ginzburg, O. V. Gendelman, R. Casalini, and A. Zaccone, arxiv:2409.17291), we demonstrated that the dynamic (relaxation time) and volume equations of state for many amorphous polymers are near-universal -- each…
When the cooling rate $v$ is smaller than a certain material-dependent threshold, the glass transition temperature $T_g$ becomes to a certain degree the "material parameter" being nearly independent on the cooling rate. The common method to…
Describing the dynamics and thermodynamics of amorphous materials near the glass transition is a major challenge in soft-matter physics and polymer engineering. Here, we show that the dependence of the dielectric alpha-relaxation time on…
The viscoelastic properties of thin polymeric films represent a central issue, especially for nanotechnological applications. In particular, it is highly relevant the dependence of viscoelasticity on the temperature. For polystyrene it is…
Aging dynamics in thin films of poly(methyl methacrylate) (PMMA) have been investigated through dielectric measurements for different types of aging processes. The dielectric constant was found to decrease with increasing aging time at an…
The molecular mobility of glassy and supercooled liquid states of clotrimazole is studied using broadband dielectric spectroscopy for a wide range of temperatures and frequency. The dielectric loss data of clotrimazole below T$_{g}$, do not…