Latex Film Formation Probed by Nonradiative Energy Transfer:  Effect of Grafted and Free Poly(ethylene oxide) on a Poly(n-butyl methacrylate) Latex

Abstract

The formation of solid films from latex dispersions is studied using particles labeled with phenanthrene or anthracene comprised of either poly(n-butyl methacrylate) (PBMA) or a copolymer of n-butyl methacrylate with a poly(ethylene oxide) (PEO) macromonomer, co(PBMA-PEO). Interparticle polymer diffusion was followed by nonradiative electronic energy transfer (DET) between electronically excited phenanthrene and anthracene. A model of energy transfer that considers both the topological constraints and the heterogeneous distributions of donors and acceptors is presented. The analysis of the phenanthrene decay curves allows calculation of the diffusion coefficient as a unique parameter, for several annealing times. The values recovered decrease initially with annealing time, which was attributed mainly to the polydispersity of the PBMA. The addition of a small percentage of low molecular weight PEO (in the form of nonylphenolethoxylate) to the PBMA particles increases the diffusion coefficient, this effect resulting from the increase of the polymer free volume in the film. When the same percentage of PEO is incorporated in the PBMA polymer chain in the form of a grafted macromonomer, the fraction of mixing increases on drying, but during annealing the diffusion coefficients remain equal to that of PBMA without PEO.

Functional Films from Silica/Polymer Nanoparticles

“…The last step in the mechanism of film formation in hybrid silica-polymer coatings can be studied using the techniques developed for studying polymer interdiffusion across the interfaces in films cast from polymer colloidal dispersions (latex). Among this, Förster resonance energy transfer (FRET) has been widely used [ 46 , 54 ] to study the effects of different factors on latex film formation, such as temperature [ 55 ], composition [ 56 ], moisture [ 57 ], coalescing aids [ 58 – 61 ], polar groups at the latex surface [ 62 , 63 ] and the presence of filler particles [ 21 , 27 , 64 ]. The use of this technique requires that the polymer is labeled with a small amount (typically less than 1 mol%) of two different dyes: a fluorescent energy donor dye and an energy acceptor dye, for which the fluorescence spectra of the donor overlaps the absorption spectra of the acceptor [ 65 ].…”

Overview of Silica-Polymer Nanostructures for Waterborne High-Performance Coatings

“…FRET can give information on the mixing of polymers labeled with donor and acceptor dyes in a wide range geometries [ 15 , 16 , 17 , 18 ], allowing the experimental determination of dye concentration profiles in complex nanostructured materials [ 19 ]. FRET has been used to study the effects of different factors on the formation of waterborne coatings, such as curing temperature [ 20 ], plasticizers [ 21 ], blending [ 22 ], crosslinkers [ 23 , 24 , 25 ], and the presence of filler particles [ 26 , 27 , 28 , 29 ].…”

Site Percolation Model for Latex Film Formation in Soft Polymer Matrix

“…Data analysis using DET improved later by taking into account the donor and acceptor concentration profiles during interdiffusion where a uniform acceptor concentration was considered around a donor in thin slices or shells (15,16). Further models for DET was developed which considered the heterogeneity in the donor and acceptor concentration profiles (17,18). Various factors have proven to affect the rate of polymer interdiffusion during latex film formation, which are water, coalescing aids, and organic solvents.…”