Fluorescence studies of coalescence and film formation in poly(methyl methacrylate) nonaqueous dispersion particles

Pekcan, Önder; Winnik, Mitchell A.; Croucher, Melvin D.

doi:10.1021/ma00212a013

Cited by 144 publications

(111 citation statements)

References 4 publications

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“…transfer (DET), [32][33][34][35][36] small-angle X-ray scattering (SAXS), 21,[37][38][39][40] atomic force microscopy (AFM) 19,41,42 and solid state NMR 42,43 haven been established to investigate latex film formation and dry particle sintering. Most of these methods need a quite elaborate experimental setup or a specific labelling with dyes/ deuterated compounds of the sample.…”

Section: Introductionmentioning

confidence: 99%

Interfacial and volumetric sensitivity of the dry sintering process of polymer colloidal crystals: a thermal transport and photonic bandgap study

Nutz

Retsch

2017

Phys. Chem. Chem. Phys.

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We introduce the in situ characterization of the dry sintering process of face-centred cubic colloidal crystals by two complementary techniques: thermal transport and photonic stopband characterization.Therefore, we employed time-dependent, isothermal laser flash analysis and specular reflectivity experiments close to the glass transition temperature of the colloidal crystal. Both methods yield distinctly different time constants of the film formation process. This discrepancy can be attributed to a volume-(photonic stopband) and interface-driven (thermal transport) sensitivity of the respective characterization method. Nevertheless, both methods yield comparable apparent activation energies.Finally, we extended the sintering process characterization to further polymer compositions, with vastly different glass transition temperatures. We could show that the film formation rate is governed by the viscoelastic properties of the polymers at the respective annealing temperature.

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Section: Introductionmentioning

confidence: 99%

Interfacial and volumetric sensitivity of the dry sintering process of polymer colloidal crystals: a thermal transport and photonic bandgap study

Nutz

Retsch

2017

Phys. Chem. Chem. Phys.

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“…It was observed that the radius of the deuterated particle increased in time as the film was annealed 11 and as the polymer molecules diffused out of the space to which they were originally confined. The process of interparticle polymer diffusion has also been studied by the direct energy transfer (DET) method, using transient fluorescence measurements 12,13 in conjunction with latex particles labeled with donor and acceptor chromophores. The steady-state fluorescence (SSF) method combined with DET was also used for studying film formation from hard latex particles.…”

Section: Introductionmentioning

confidence: 99%

Photon transmission method for studying film formation from polstyrene latexes with different molecular weights

Pekcan

Arda

Bulmuş

et al. 2000

J. Appl. Polym. Sci.

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A photon-transmission method was used to probe the evolution of transparency during film formation from polystyrene (PS) particles with different molecular weights. The latex films were formed at room temperature from the PS particles having two different average molecular weights and annealed at elevated temperatures in various time intervals above the glass transition (T g ). Onset temperatures (T H ) at given times ( H ) for the optical clarity of films formed from low (LM) and high molecular (HM) weight PS particles were used to calculate the healing activation energies for the minor chains and found to be 22.0 Ϯ 0.5 and 27.0 Ϯ 0.6 kcal/mol, respectively. The increase in the transmitted photon intensity, I tr , above the T H was attributed to increase in the number of interfaces that disappeared. The Prager-Tirrell (PT) model was employed to interpret the increase in crossing density at the junction surface. The backbone activation energies (⌬E) were measured and found to be 127.8 Ϯ 2.5 kcal/mol for a diffusing polymer chain across the junction surface for LM and HM latex films.

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“…Extensive studies using SANS have been performed by Sperling and coworkers 8 on compression-molded PS films. The direct nonradiative energy transfer (DET) method has been employed to investigate the film-formation processes from dye-labeled hard 9 and soft 10,11 polymeric particles. The steady-state fluorescence (SSF) technique combined with DET was recently used to examine healing and interdiffusion processes in dye-labeled hard latex systems.…”

Section: Introductionmentioning

confidence: 99%

Effect of molecular weight on latex film formation: Photon transmission study

Pekcan

Arda

1998

J. Appl. Polym. Sci.

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A UV-visible (UVV) technique was used to monitor the evolution of transparency during film formation from hard latex particles. Two different latex films were prepared from particles with high and low molecular weight (HM and LM) poly(methyl methacrylate) (PMMA) separately and annealed at elevated temperatures in various time intervals above the glass transition temperature (T g ). In both films, a continuous increase in the transmitted photon intensity (I tr ) was observed above 160°C as the annealing temperature was increased. However, the reflected photon intensity (I rf ) first decreased and then increased by showing a minimum in the same temperature range as the annealing temperature was increased. The increase in the transmitted photon intensity (I tr ) is attributed to increase in the "crossing density" at the junction surface. The activation energies for back-and-forth motion (⌬E tr ) were measured and found to be around 35 and 25 kcal/mol for the reptating polymer chain across the junction surface in the LM and HM films, respectively. The decrease in I rf was explained by the void-closure mechanism, and the increase in the I rf above 160°C was again attributed to the increase in the crossing density at the junction surface. Back-and-forth activation energies (⌬E rf ) were measured to be around 47 and 18 kcal/mol and the void-closure constants (B) were found to be around 24 ϫ 10 3 and 12 ϫ 10 3 K for the LM and HM film samples, respectively.

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Fluorescence studies of coalescence and film formation in poly(methyl methacrylate) nonaqueous dispersion particles

Cited by 144 publications

References 4 publications

Interfacial and volumetric sensitivity of the dry sintering process of polymer colloidal crystals: a thermal transport and photonic bandgap study

Interfacial and volumetric sensitivity of the dry sintering process of polymer colloidal crystals: a thermal transport and photonic bandgap study

Photon transmission method for studying film formation from polstyrene latexes with different molecular weights

Effect of molecular weight on latex film formation: Photon transmission study

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