Turbidity study of the process of film formation of polymer particles in drying thin films of acrylic latices

The onset of polymer diffusion in a drying acrylate latex: how water initially retards coalescence but ultimately enhances diffusion

“…The system consists of a pulsed diode for sample excitation, with focusing optics to limit the spot size to less than 1 mm. 2 It also contains an in-line near-infrared sensitive camera for monitoring the film and the position of sample excitation. The film is illuminated with 900 nm diodes, a wavelength detected by the camera, but not detected by the photon counting detector.…”

“…These first two steps transform the latex from a turbid dispersion into a transparent film, indicating that any remaining inhomogeneities in the film, such as voids, precipitated salts, and surfactant, or pools of water, must be small enough to not scatter light significantly. 2 In the third step of latex film formation, the diffusion of polymer chains across cell interfaces provides mechanical strength to the film, as the polymer chains from adjacent cells co-mingle and form entanglements.…”

Film formation from monodisperse acrylic latices

“…[9][10][11][12]) and gravimetry for measurements of water uptake (for more details see Refs. [14] and [25]).…”

“…This turbidity is characterized by a typical immersion pattern (transmission vs volume fraction of absorbed water in the rewetted film at a certain wavelength) which is calculated based on Rayleigh's law [9,11,14]:…”

The Film Formation of Polymer Particles in Drying Thin Films of Aqueous Acrylic Latices

“…Figure 2-Water evaporates from the bulk, resulting in a decrease of the interparticle distance (stage I). The shift of the interparticle interference minimum (λ min , spectra 1 to 4, measured after 20 s, 105 s, 165 s, and 210 s, respectively) to smaller wavelengths is related to the decrease of the interparticle distance (6). For the calculation of the interparticle distances in a drying latex film only the values of λ min are required, assuming that the latex particles are ideally packed (6).…”