We investigated the dynamics of a series of room temperature ionic liquids based on the same 1-butyl-3-methyl imidazolium cation and different anions by means of broadband dielectric spectroscopy covering 15 decades in frequency (10-10Hz), and in the temperature range from 400 K down to 35 K. An ionic conductivity is observed above the glass transition temperature Tg with a relaxation in the el...

The glass transition is a long-standing unsolved problem in materials science. For polymers, our understanding of glass-formation particularly poor due to the added complexity chain connectivity and flexibility; structural relaxation polymers thus involves complex interplay between intra- inter-molecular cooperativity. Here we study how temperature Tg varies with molecular weight M for differen...

In large area micro hot embossing, process temperature plays a critical role in both the local fidelity of microstructure formation and global uniformity. Micro embossing at the lowest temperature with acceptable fidelity can improve the global flatness after demolding. This paper focuses on polymer deformation and recovery in micro embossing when the process temperatures are below its glass tr...

The change of the compressibility at the glass transition Tg is evaluated from pressure experiments in the liquid and the glassy state of the ZrTiCuNiBe bulk metallic glass forming system. Via the enthalpy recovery method, we derive an increase of Tg with pressure of 3.6 KyGPa. Comparing the changes of the compressibility, the specific heat capacity, and the thermal expansion coefficient at Tg,...

the thin gelatin films, prepared by casting of gelatin solutions at different drying temperatures, had different molecular morphologies as monitored, using wide angle x-ray diffraction (waxd) and differential scanning calorimetry (dsc) techniques. it was revealed that gelatin films dried at lower temperatures showed markedly higher crystalline or helical structure with slightly higher tg and lo...

OBJECTIVE This study evaluated the glass transition temperature (Tg) and degree of conversion (DC) of a light-cured (Fill Magic) versus a chemically cured (Concise) orthodontic composite. MATERIAL AND METHODS Anelastic relaxation spectroscopy was used for the first time to determine the Tg of a dental composite, while the DC was evaluated by infrared spectroscopy. The light-cured composite sp...

Shape-memory materials (including polymers, metals, and ceramics) are those that are processed into a temporary shape and respond to some external stimuli (e.g., temperature) to undergo a transition back to a permanent shape. Shape memory polymers are finding use in a range of applications from aerospace to fabrics, to biomedical devices and microsystem components. For many applications, it wou...

By utilizing ultrasonic annealing at a temperature below (or near) the glass transition temperature Tg, we revealed a microstructural pattern of a partially crystallized Pd-based metallic glass with a high-resolution electron microscopy. On the basis of the observed microstructure, we inferred a plausible microstructural model of fragile metallic glasses composed of strongly bonded regions surr...

Densification of oxide glasses at the glass transition offers a novel route to develop bulk glasses with tailored properties for emerging applications. Such densification can be achieved in the technologically relevant pressure regime of up to ~1 GPa. However, the present understanding of the composition–structure–property relationships governing these glasses is limited, with key questions, e....