2134/37396
Ignacio Martin-Fabiani
Ignacio
Martin-Fabiani
David K. Makepeace
David K.
Makepeace
Philip G. Richardson
Philip G.
Richardson
Jennifer Lesage de la Haye
Jennifer Lesage
de la Haye
Diego Alba Venero
Diego Alba
Venero
Sarah E. Rogers
Sarah E.
Rogers
Franck D’Agosto
Franck
D’Agosto
Muriel Lansalot
Muriel
Lansalot
Joseph L. Keddie
Joseph L.
Keddie
In situ monitoring of latex film formation by small-angle neutron scattering: Evolving distributions of hydrophilic stabilizers in drying colloidal films
Loughborough University
2019
Surfactant
Waterborne
macroRAFT
Small-angle neutron scattering
Latex
Free energy
Interfacial energy
Materials Engineering not elsewhere classified
2019-04-02 10:30:06
Journal contribution
https://repository.lboro.ac.uk/articles/journal_contribution/In_situ_monitoring_of_latex_film_formation_by_small-angle_neutron_scattering_Evolving_distributions_of_hydrophilic_stabilizers_in_drying_colloidal_films/9236666
The distribution of hydrophilic species, such as surfactants, in latex films is of critical importance for the performance of adhesives, coatings and inks, among others. However, the evolution of this distribution during the film formation process and in the resulting dried films remains insufficiently elucidated. Here, we present in situ (wet) and ex situ (dry) SANS experiments that follow the film formation of two types of latex particles, which differ in their stabilizer: either a covalently bonded poly(methacrylic acid) (PMAA) segment or a physically adsorbed surfactant (sodium dodecyl sulfate, SDS). By fitting the experimental SANS data and combining with gravimetry experiments, we have ascertained the hydrophilic species distribution within the drying film and followed its evolution by correlating the size and shape of stabilizer clusters with the drying time. The evolution of the SDS distribution over drying time is being driven by a reduction in the interfacial free energy. However, the PMAA-based stabilizer macromolecules are restricted by their covalent bonding to core polymer chains and hence form high surface-area disc-like phases at the common boundary between particles and PMAA micelles. Contrary to an idealized view of film formation, the PMAA does not remain in the walls of a continuous honeycomb structure. The results presented here shed new light on the nanoscale distribution of hydrophilic species in drying and ageing latex films. We provide valuable insights into the influence of the stabilizer mobility on the final structure of latex films.