The surface relief gratings (SRGs) can be generated when azo-polymer films are exposed to laser beam interference as a result of mass migration. Despite considerable research effort over the past two decades this complex phenomenon remains incompletely understood. Here we show, for the first time, the athermal photofluidisation of azo-polysiloxane films exposed to 488 nm light, directly monitored by optical microscopy. A process of surface relief erasure occurring in parallel with its inscription was also observed during laser irradiation. We therefore propose a new mechanism of SRG formation, based on three different processes: (1) the polymer photo-fluidization in illuminated regions, (2) the mass displacement from illuminated to dark regions and (3) the inverse mass displacement, from dark to illuminated regions. The mechanical properties of the films during UV light irradiation were investigated by classical rheology and, for the first time, by using amplitude modulation-frequency modulation atomic force microscopy (AM-FM AFM).

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The present paper is focused on the study of the thermal behavior of casein, the main protein in milk, by applying the TG-FTIR technique and calorimetric measurements. The research is of a great interest due to the large application areas of casein in cosmetic, food and pharmaceutical industries. The analysis of the thermal behavior by the TG-DTG-DTA methods allwos the finding of the temperature range where the casein is thermally stable and the caseincontaining cosmetics, food and pharmaceutical products proper for using. The identification of the gaseous species released allwos the TG-FTIR coupled technique to give useful information on the possible environmental impact when the casein-containing products are used at temperatures above the casein initial degradation temperature. The combustion heat of casein estimated by means of the Berthelot calorimeter made evident this value to be close to those of the most important and used fuels which would recommend the waste casein-containing products to be used as fuels.

This paper presents a thermogravimetric study of azo-polysiloxanic materials that may be used as supports for cells culture. This type of polymer may generate nanostructured surfaces when subjected to laser irradiation, yielding a cell response that depends on surface relief. Modification of cell growth supports using nanostructured synthetic materials improves general understanding of the complex mechanisms that control cell adhesion and migration in normal conditions, as well as in various pathologies. These polymers require good thermal stability, since they need to be able to withstand both the interaction with the laser source, as well as various sterilization processes, without noticeable alteration in structure and properties. Thermal stability analysis confirms that the azo-polysiloxanic materials under study here may be used up to 300 °C in dynamic temperature conditions and also for a period of 40 minutes in isothermal conditions at 180 °C.