James A. Forrest
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View article: Two relaxation mechanisms for rejuvenation of stable polymer glass
Two relaxation mechanisms for rejuvenation of stable polymer glass Open
We report on the rejuvenation of thin films of polystyrene (PS) as they are heated from stable glassy states - prepared either through vapour deposition or physical aging. For films with thickness $h \gtrsim 200$ nm, the rejuvenation of va…
View article: Measurement of the depth-dependent local dynamics in thin polymer films through rejuvenation of ultrastable glasses
Measurement of the depth-dependent local dynamics in thin polymer films through rejuvenation of ultrastable glasses Open
The depth dependence of structural relaxation dynamics is a key part of understanding thin glassy films. Despite this importance and decades of research, a method to provide this information has proved elusive. We measure the isothermal re…
View article: Measurement of the depth-dependent local dynamics in thin polymer films through rejuvenation of ultrastable glasses
Measurement of the depth-dependent local dynamics in thin polymer films through rejuvenation of ultrastable glasses Open
We measure the isothermal rejuvenation of stable glass films of poly(styrene) and poly(methylmethacrylate). We demonstrate that the propagation of the front responsible for the transformation to a supercooled-liquid state can serve as a hi…
View article: Surface and bulk relaxation of vapor-deposited polystyrene glasses
Surface and bulk relaxation of vapor-deposited polystyrene glasses Open
We have studied the liquid-like response of the surface of vapor-deposited glassy films of polystyrene to the introduction of gold nanoparticles on the surface. The build-up of polymer material was measured as a function of time and temper…
View article: Acoustic transmission loss of a fluid-filled rubber hose
Acoustic transmission loss of a fluid-filled rubber hose Open
Flexible rubber hoses can provide significant\nattenuation of vibro-acoustic energy in fluid-filled piping systems. The vibroacoustic performance of rubber hoses can be measured by using a variation of a water-filled impedance tube, using …
View article: On the bridge hypothesis in the glass transition of freestanding polymer films
On the bridge hypothesis in the glass transition of freestanding polymer films Open
Freestanding thin polymer films with high molecular weights exhibit an anomalous decrease in the glass-transition temperature with film thickness. Specifically, in such materials, the measured glass-transition temperature evolves in an aff…
View article: Surface and Bulk Relaxation of Vapour-Deposited Polystyrene Glasses
Surface and Bulk Relaxation of Vapour-Deposited Polystyrene Glasses Open
We have studied the liquid-like response of the surface of vapour-deposited glassy films of polystyrene to the introduction of gold nanoparticles on the surface. The build-up of polymer material was measured as a function of time and tempe…
View article: Cooperative strings and glassy dynamics in various confined geometries
Cooperative strings and glassy dynamics in various confined geometries Open
Previously, we developed a minimal model based on random cooperative strings for the relaxation of supercooled liquids in the bulk and near free interfaces, and we recovered some key experimental observations. In this article, after recall…
View article: Using<i>M</i><sub>w</sub>Dependence of Surface Dynamics of Glassy Polymers to Probe the Length Scale of Free-Surface Mobility
Using<i>M</i><sub>w</sub>Dependence of Surface Dynamics of Glassy Polymers to Probe the Length Scale of Free-Surface Mobility Open
We\ndescribe a series of surface-leveling experiments in glassy\npolystyrene of varying molecular weight. The evolution through a mobile\nsurface layer is described by the glassy thin film equation that was\nintroduced and used in a previo…
View article: Correction: Cooperative strings in glassy nanoparticles
Correction: Cooperative strings in glassy nanoparticles Open
Correction for 'Cooperative strings in glassy nanoparticles' by Maxence Arutkin et al., Soft Matter, 2017, 13, 141-146.
View article: Glass transition at interfaces
Glass transition at interfaces Open
We live in the twenty-first century. Almost all the changes between phases of matter\nare described by the theory of phase transitions. Yet, there is one phenomenon that\nstill resists theoretical attempts at its description: the glass tra…
View article: Controlling Marangoni induced instabilities in spin-cast polymer films: how to prepare uniform films
Controlling Marangoni induced instabilities in spin-cast polymer films: how to prepare uniform films Open
In both research and industrial settings spin coating is extensively used to prepare highly uniform thin polymer films. However, under certain conditions, spin coating results in films with non-uniform surface morphologies. Although the sp…
View article: Cooperative strings in glassy nanoparticles
Cooperative strings in glassy nanoparticles Open
Motivated by recent experimental results on glassy polymer nanoparticles, we develop a minimal theoretical framework for the glass transition in spherical confinement. This is accomplished using our cooperative-string model for supercooled…
View article: Cooperative strings and glassy interfaces
Cooperative strings and glassy interfaces Open
Significance According to Philip Anderson, the deepest and most interesting unsolved problem in solid-state physics is probably the glass transition. By extension, this includes the highly debated confinement effects in glassy polymer film…
View article: Glass Transition, Cooperativity and Interfaces
Glass Transition, Cooperativity and Interfaces Open
We introduce a minimal theory of glass formation based on the physical ideas of molecular crowding and resultant cooperative motion, and address the effects of free interfaces on dynamics. First, we obtain a simple scaling expression for t…