We employ positron annihilation lifetime spectroscopy (PALS) to measure the temperature dependent fluctuations in a local free volume of water confined in a variety of mesoporous materials with different pore sizes and morphologies. We demonstrate that this unconventional approach can be used to probe the dynamics and glass transition temperature, Tg, of water in confinement. In the simplest ca...

It is a challenge to calorimetrically determine the glass transition temperature (Tg) of vitreous silica. Here, we demonstrate that this challenge mainly arises from the extremely high sensitivity of the Tg to the hydroxyl content, but also from decrease of the Tg with repeating the calorimetric scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercoo...

The effects of glass transition of, and protein conformation in, the dried solid on the storage stability of freeze-dried recombinant human interleukin-1 receptor antagonist (rhIL-1ra) were examined. Glass transition is a temperature-dependent phenomenon. Amorphous materials become hard and brittle at temperatures below their characteristic glass transition temperatures (Tg) such that diffusion...

Long-term storage of viable mammalian cells is important for applications ranging from in vitro fertilization to cell therapy. Cryopreservation is currently the most common approach, but storage in liquid nitrogen is relatively costly and the requirement for low temperatures during shipping is inconvenient. Desiccation is an alternative strategy with the potential to enable viable cell preserva...

Studying the thermophysical properties of disaccharide based ternary solutions are gaining increasing importance because of their role as excepients in preservation protocols for biologics in general and mammalian cells in particular. Preservation strategies involve not only cryopreservation, but novel approaches like room temperature vitrification and lyophilization. In this study we investiga...

We report computation results obtained from extensive coarse-grained molecular-dynamics simulations of amorphous ensembles of polymer chains at constant density. In our polymer model, we use bending and torsion potentials acting along the polymer backbone to control the chain stiffness. The static and dynamic properties of the polymer bulk have been analyzed over a large temperature interval in...

The range of magnitude of the liquid viscosity, η, as a function of temperature is one of the most impressive of any physical property, changing by approximately 17 orders of magnitude from its extrapolated value at infinite temperature (ηo) to that at the glass transition temperature, Tg. We present experimental measurements of containerlessly processed metallic liquids that suggest that log(η...

PVT (Pressure-Volume-Temperature) properties of polymers are important for both engineering and polymer physics. Fig.1 shows the typical PVT diagrams of an amorphous (a) and semi-crystalline polymer (b). PVT diagram describes the specific volume as a function of pressure and temperature. Specific volume increases with the temperature increasing. There is a thermal transition in the polymer. The...

To analyze the photothermal ablation of polymers, we designed a temperature measurement setup based on spectral pyrometry. The setup allows to acquire 2D temperature distributions with 1 μm size and 1 μs time resolution and therefore the determination of the center temperature of a laser heating process. Finite element simulations were used to verify and understand the heat conversion and heat ...

In this paper we present a new analysis of data on the reduced glass transitions observed in thin freely-standing films. The empirical analysis presented is highly suggestive of the existence of a mechanism of mobility in thin freely-standing films that is inhibited in the bulk and distinct from the usual cooperative motion near the glass transition temperature Tg. A tentative mechanism for Tg ...