The nano/micro scale thermal diffusivity in soft materials are important due to the increasing demand for functional thermal properties arising from their wide variety of multiscale high order structures. In the physical point of view, the advanced measurement techniques for the investigation of the thermophysical properties begin to be recognized as the way to understand the internal dynamics and structure of soft materials. The determination of the thermal diffusivity using temperature wave analysis (TWA) method is robust and has been applied to many systems including nano/micro sensing devices. In this study, recent advances in the instrumentation of TWA method targeting nano/micro scale thermal diffusivity are reported. The method is based on the development of integrated devices having micro heating module and sensing module for the periodic heating and the periodic temperature response from the sample. The cantilever type devices are also utilized for TWA method to realize the measurement in the scanning probe system. The microscale structure of soft materials such as micro structure of the chemically amplified photoresist or the composite between PMMA and highly aligned graphene were investigated. TWA based micro/nano scale measurement can be applied further to the thermal diffusivity in localized structure of soft materials.

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This review reorganizes our recent study on a 20 wt% bovine serum albumin (BSA) aqueous solution, focusing on the role of thermal history in water dynamics. Adiabatic calorimetry and dielectric relaxation measurements under comparable thermal protocols revealed an endothermic peak at ~72 K only in quenched samples, attributed to a transition from proton-ordered ice XI to proton-disordered ice Ih, indicating partial proton ordering prior to heating. The low-temperature anomaly around 110 K is reassigned as a superposition of the glass transition of primary hydration water and proton reorientation in ice Ih. While these processes can be distinguished in dielectric measurements, they overlap in calorimetry. A faster relaxation observed only in quenched samples is discussed in relation to ice XI formation, although its mechanism remains unclear. These results highlight the importance of thermal history and the coexistence of multiple water states in protein aqueous systems.

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Recently, meltable coordination polymers (CPs) have attracted attention because of their unusual melting behavior, glass-forming ability, and processability. Herein, we describe the crystal structures and thermal properties of CPs with the formula {[cation][MX2]}n, prepared by reacting metal salts MX with ionic liquids (ILs) [cation]X, where M is an alkali metal and X is a polycyano anion. These materials were designed to lower the melting points of CPs by incorporating IL components. Their crystal structures consist of two- or three-dimensional anionic frameworks, [MX2]n−, that accommodate the cations. Upon heating, most of the CPs undergo incongruent melting with precipitation of the metal salt MX. The melting points of the CPs decrease with decreasing melting points of the parent salts. Upon further heating above the melting point, the precipitated metal salt gradually dissolves to form a homogeneous liquid. This liquid recrystallizes upon cooling, whereas rapid cooling leads to glass formation. CPs containing more rigid cations require higher cooling rates to achieve vitrification.

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Fullerene C60 has been confirmed as an interstellar molecule since its infrared (IR) emission bands were identified in spectra of a young planetary nebula, namely Tc 1, in 2010, by observation using a space telescope of Spitzer/IRS. In order to provide experimental and theoretical backgrounds needed for estimation of vibrational temperature and molecular abundance in space, IR emission spectra of C60 thin films were measured in the laboratory and temperature dependence of the IR emission intensity was examined experimentally for four IR-active T1u modes of C60. Based on spontaneous emission from thermally populated vibrationally excited levels in a C60 molecule, theoretical simulations were performed on IR emission intensity at elevated temperatures. Thereby, it was clarified how and why the IR emission spectra change by different temperatures. Depending on the vibrational-mode frequencies, temperature dependence of the IR-emission intensity differs, thus relative intensity of these IR-emission bands can be exploited as thermometer of vibrational temperature for far distant molecules.

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Development of a thermal conductivity measurement system designed for micro-size single crystals of molecular compounds is reported. This construction aims at measuring absolute values of thermal conductivity and its temperature dependence in a wide temperature range from 0.5 K to near room temperature. To investigate electronic states at low temperatures by this system, it is possible to measure thermal conductivity with external magnetic fields up to 10 T by using RuO2 thermometers. Furthermore, we describe a low-noise switching unit designed for this thermal conductivity measurement system, which allows smooth switching from RuO₂ thermometers for the low-temperature range to type-E thermocouple sensors for temperatures above 10 K without modifying sample set-up and connection of electronics. Using this extension of availability, we conducted an automated high-precision thermal conductivity measurement of small manganin rod-shaped samples for calibration. We also report analyses of the additional noises introduced by this switching system measured by the ac resistance bridge and thermocouples. Furthermore, we examined a method for correcting the effects of radiation heat loss which are inherent to the steady-state measurements typically performed above 150K effectively. This research improves the feasibility of the thermal conductivity measurement over a wide temperature range for molecular compounds in which a variety of electronic states emerging with interesting phonon dynamics.

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