Effect of Local Chain Conformation in Adsorbed Nanolayers on Confined Polymer Molecular Mobility

Zuo, Biao; Zhou, Hao; Davis, Mary J. B.; Wang, Xinping; Priestley, Rodney D.

doi:10.1103/physrevlett.122.217801

Cited by 103 publications

(135 citation statements)

References 50 publications

Supporting

Mentioning

132

Contrasting

Order By: Relevance

“…Essential to successful implementation of polymer thin films is a framework for understanding and anticipating the often substantial impacts of processing and geometry on film properties 4–6. A notable example is the growth of an irreversibly adsorbed nanolayer at the polymer‐substrate interface7–14 induced by annealing a polymer above its glass transition temperature ( T g ). This nanolayer, which gradually approaches a quasi‐equilibrium, or plateau, thickness with increased annealing time ( t ann ),15 has particularly important implications for polymer thin films, as its development is closely associated with deviations from bulk T g and viscosity in thin films,11,16–19 and preparation of polymer thin films frequently requires annealing above T g .…”

Section: Figurementioning

confidence: 99%

Revealing Interfacial Interactions in Random Copolymer Adsorbed Layers by Solvent Leaching

Davis

Randazzo

Zuo

et al. 2020

Macromol. Rapid Commun.

Self Cite

View full text Add to dashboard Cite

Annealing a supported polymer film in the melt state results in the growth of an irreversibly adsorbed layer, which has been shown to influence thin film properties such as diffusion and glass transition temperature. Adsorbed layer growth is attributed to many simultaneous interactions between individual monomer units and the substrate, stabilizing chains against desorption. In this study, adsorbed layers of polystyrene (PS), poly(methyl methacrylate) (PMMA), and their random copolymers are isolated by select solvents. While PS adsorbed layer thickness is largely unaffected by the choice of washing solvent, the PMMA adsorbed layer completely desorbs when washed with tetrahydrofuran and chloroform, as opposed to toluene. Scaling relationships between adsorbed layer thickness and degree of chain adsorption at the substrate enable the use of adsorbed layer thickness to probe specific polymer‐substrate interactions. Composition‐dependent desorption trends indicate non‐preferential adsorption between styrene and methyl methacrylate repeat units at the substrate, despite differences in substrate interaction strength. This insight contributes to the developing mechanism for the adsorption of random copolymers during melt‐state annealing, further extending the ability to predict processing‐inducted changes to the properties of polymer thin films to heterogeneous systems.

show abstract

Section: Figurementioning

confidence: 99%

Revealing Interfacial Interactions in Random Copolymer Adsorbed Layers by Solvent Leaching

Davis

Randazzo

Zuo

et al. 2020

Macromol. Rapid Commun.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The number of adsorbed chains increases with polymer concentration until reaching a saturation value, given by interfacial interactions. Desorption of adsorbed chains is, hence, possible by placing a polymer layer in a pure solvent 20 , or in a solution whose concentration is lower than that related to the equilibrium adsorbed amount 4 . Importantly, the concentration thresholds to stabilize adsorbed layers are rather low, which corresponds to weak desorption forces 21 , 22 , and extremely long desorption times: soaking for 4 months in pure chloroform is not sufficient to fully desorb an adsorbed layer of polystyrene (PS) 17 .…”

Section: Introductionmentioning

confidence: 99%

Direct observation of desorption of a melt of long polymer chains

2020

View full text Add to dashboard Cite

Tuning the thermodynamic state of a material has a tremendous impact on its performance. In the case of polymers placed in proximity of a solid wall, this is possible by annealing above the glass transition temperature, T g , which induces the formation of an adsorbed layer. Whether heating to higher temperatures would result in desorption, thereby reverting the thermodynamic state of the interface, has so far remained elusive, due to the interference of degradation. Here, we employ fast scanning calorimetry, allowing to investigate the thermodynamics of the interface while heating at 10 4 K s −1. We show that applying such rate to adsorbed polymer layers permits avoiding degradation and, therefore, we provide clear-cut evidence of desorption of a polymer melt. We found that the enthalpy and temperature of desorption are independent of the annealing temperature, which, in analogy to crystallization/melting, indicates that adsorption/desorption is a first order thermodynamic transition.

show abstract

“…Nevertheless, much less attention has been paid to the confinement of SRPs inside the spherical container, especially considering SRP mixtures with polydispersity. The physical effects from the topological constraints and confinements play significant roles in the structure and function of individual genetic materials [34][35][36][37][38], such as chromosome shape in elongated bacterial cells [39], DNA (or DNA-actin filament mixtures) self-organization in a cell-size confinement [40], and drug delivery from spherical vesicles [41,42], etc.…”

Section: Introductionmentioning

confidence: 99%

Entropy-Induced Separation of Binary Semiflexible Ring Polymer Mixtures in Spherical Confinement

Zhou¹,

Guo²,

Li³

et al. 2019

Polymers

View full text Add to dashboard Cite

Coarse-grained molecular dynamics simulations are used to investigate the conformations of binary semiflexible ring polymers (SRPs) of two different lengths confined in a hard sphere. Segregated structures of SRPs in binary mixtures are strongly dependent upon the number density of system (ρ), the bending energy of long SRPs (Kb, long), and the chain length ratio of long to short SRPs (α). With a low ρ or a weak Kb, long at a small ratio α, long SRPs are immersed randomly in the matrix of short SRPs. As ρ and bending energy of long SRPs (Kb, long) are increased up to a certain value for a large ratio α, a nearly complete segregation between long and short SRPs is observed, which can be further characterized by the ratio of tangential and radial components of long SRPs velocity. These explicit segregated structures of the two components in spherical confinement are induced by a delicate competition between the entropic excluded volume (depletion) effects and bending contributions.

show abstract

Effect of Local Chain Conformation in Adsorbed Nanolayers on Confined Polymer Molecular Mobility

Cited by 103 publications

References 50 publications

Revealing Interfacial Interactions in Random Copolymer Adsorbed Layers by Solvent Leaching

Revealing Interfacial Interactions in Random Copolymer Adsorbed Layers by Solvent Leaching

Direct observation of desorption of a melt of long polymer chains

Entropy-Induced Separation of Binary Semiflexible Ring Polymer Mixtures in Spherical Confinement

Contact Info

Product

Resources

About