Contact angle time-temperature dependence

The time-temperature dependence of the contact angle, as expressed by Equation 2.30, may be combined with Poiseuille s law. Equation 2.27, and integrated to yield [139] ... 

Finally, an important feature of gels made of adhesive emulsions arises from the deformation of the droplets. Indeed, as the temperature is lowered the contact angles between the droplets increase [27,28] (see Chapter 2, Section 2.3). Consequently, the structure of the final floes depends on the time evolution of the strength of the adhesion. Initially, the adhesion results in the formation of a random, solid gel network in the emulsion. Further increase of adhesion causes massive fracturing of the gel, disrupting the rigidity of the structure and leading to well separated, and more compact floes [27,28]. 

The temperature-dependent NMR spectra of the PLA samples collected under the varying temperature from 20 to 80 °C are shown in Fig. 6. Cross polarization-magic angle spinning (CP-MAS) NMR experiments were carried out on a Varian 400 NMR system spectrometer operated at 100.56 MHz for resonance with a cross polarization contact time of 2 ms (Fawcett, 1996). A zirconium oxide rotor of 4 mm diameter was used to acquire the NMR spectra at a spinning rate of 15 kHz. Each sample was packed into a 4 mm cyUnder-type MAS rotor. A set of temperature-dependent NMR spectra were obtained under varying ambient temperature from 20 to 80 °C at every 20 °C step. The heating rate was approximately 10 °C per an hour. 

Fig. 3.15 Plots of the time-dependent contact angles for the monomer at substrate temperatures of 22 °C and 95 °C on (a) DTC-coated BOPP, (b) Hexo-coated BOPP, (c) DTC-coated SGE, and (d) Flexo-coated SGE (Reproduced with permission from [42], Copyright 2013 The American Chemical Society)...

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