Large-Scale Diffusion of Entangled Polymers along Nanochannels

Lange, Frank de; Judeinstein, Patrick; Franz, Cornelius; Hartmann‐Azanza, Brigitte; Ok, Salim; Steinhart, Martin; Saalwächter, Kay

doi:10.1021/acsmacrolett.5b00213

Cited by 37 publications

(53 citation statements)

References 36 publications

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“…A reduction of the diffusivity appeared depending on the pore diameter but not on the molecular weight for short polymers (molecular weight between 2 and 24 kDa). This behavior was rationalized in terms of the monomeric friction coefficient, which suggested a 10-times enhanced friction due to the surface in a single molecular layer [73]. Moreover, by using elastic recoil detection, PS tracer diffusivity along the cylindrical aluminim oxide membranes was measured and an increase in comparison to the bulk value was observed as the confinement increases, in agreement with other studies [74].…”

Section: Methodssupporting

confidence: 84%

“…That discrepancy was due to PMMA-GO interaction [71]. Furthermore, the self-diffusion of confined poly(butadiene) chains in alumina channels (100 µm long, 20 and 60 nm wide) was investigated [73] by proton pulsed-gradient NMR. A reduction of the diffusivity appeared depending on the pore diameter but not on the molecular weight for short polymers (molecular weight between 2 and 24 kDa).…”

Section: Methodsmentioning

confidence: 99%

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Modeling of Entangled Polymer Diffusion in Melts and Nanocomposites: A Review

et al. 2019

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This review concerns modeling studies of the fundamental problem of entangled (reptational) homopolymer diffusion in melts and nanocomposite materials in comparison to experiments. In polymer melts, the developed united atom and multibead spring models predict an exponent of the molecular weight dependence to the polymer diffusion very similar to experiments and the tube reptation model. There are rather unexplored parameters that can influence polymer diffusion such as polymer semiflexibility or polydispersity, leading to a different exponent. Models with soft potentials or slip-springs can estimate accurately the tube model predictions in polymer melts enabling us to reach larger length scales and simulate well entangled polymers. However, in polymer nanocomposites, reptational polymer diffusion is more complicated due to nanoparticle fillers size, loading, geometry and polymer-nanoparticle interactions.

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Section: Methodssupporting

confidence: 84%

Section: Methodsmentioning

confidence: 99%

Modeling of Entangled Polymer Diffusion in Melts and Nanocomposites: A Review

et al. 2019

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“…The latter is in keeping with Lange et al's measurement that for unentangled to mildly entangled polybutadiene in AAO nano channels, the amount of diffusivity reduction only depended on the channel size but not M w . 42 …”

Section: ) Shown Inmentioning

confidence: 99%

Viscosity and Surface-Promoted Slippage of Thin Polymer Films Supported by a Solid Substrate

Chen¹,

Peng²,

Lam

et al. 2015

Macromolecules

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Thermally activated flow dynamics of polystyrene films supported by silicon is studied for a wide range of film thickness (h 0 ) and molecular weights (M w ). At low M w , the effective viscosity of the nanometer thin films is smaller than the bulk and decreases with decreasing h 0 . This is due to enhancement of the total shear flow by the augmented mobility at the free surface. As M w increases, with h 0 becoming smaller than the polymer radius of gyration (R g ), the effective viscosity switches from being substrate-independent to substrate-dependent. We propose that interfacial slippage then dominates and leads to plug flow. The friction coefficient is found to increase with h 0 providing h 0 /R g < ∼1, demonstrating a surface-promoted confinement effect. ■ INTRODUCTIONMany recent experiments reveal that polymer under confinement in the nanometer range often exhibits dynamics distinguishably different from the bulk. 1−5 While the mechanisms underpinning the new properties are still controversial, most results suggest that they originate from surface effects. Usually, the chain dynamics near the free (air) surface is faster than the bulk 6−11 but that near the substrate is slower. 12,13 By embracing analogous effects in a layer model, variations in the dynamic properties, including the glass transition temperature, T g , 10,14,15 and effective viscosity, η eff , 8,12,16 with the average polymer thickness, h 0 , were explained. At high molecular weights, M w , where the unperturbed radius of gyration, R g , exceeds ∼h 0 , de Gennes further proposed that the highmobility chain segments at the free surface can bring about mobility enhancement to the whole chain through chain connectivity. 17 Here, we report a comprehensive study on the η eff of polystyrene supported by oxide-coated Si (PS-SiOx; SiOx thickness = 102 ± 5 nm) with 13 ≤ M w ≤ 2300 kg/mol (∼3 < R g < ∼41 nm (Supporting Information)), polydispersity index 1.01−1.1, and h 0 /R g from ∼0.2 to ∼10. A new dynamic regime dominated by plug flow and instigated by a surface-promoted confinement effect is found. ■ EXPERIMENTAL METHODSPolystyrene (PS), with a weight-average molecular weight, M w , of 13.7−2300 kg/mol and polydispersity index of 1.01−1.1, was purchased from Scientific Polymer Products (Ontario, NY). In this experiment, we use as-cast films made from spin-coating. Methods of sample preparation and characterization have been reported before. 8,18 In brief, the as-purchased polymer granules are first dissolved in toluene, and then the solution is filtered through a PTFE membrane filter with pore size 0.1 μm (Fisher Scientific Co.) before being spincoated onto a substrate to form the films. The substrates, purchased from Siltronix (France), are single crystal (001) silicon wafers covered by a 102 ± 5 nm thick thermal oxide. Before use, the wafers are cut into 1.5 cm × 1.5 cm slides and submerged in a piranha solution at 130°C for 10 min, followed by thorough rinsing in deionized water and then drying by 99.99% nitrogen. Afterward, the slides are furt...

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“…Recently, many research groups have devoted attention to exploration of the effects of AAO nanoconfinement, which alters physical, chemical, and mechanical properties, on molecular dynamics, molecular orientation, morphology transformation [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50], and so forth. Especially, nanoconfinement effects on various geometries have been reported to influence the thermal glass transition of amorphous polymers [43].…”

Section: Thermal Properties and Molecular Orientation Of Polymer Nanomentioning

confidence: 99%

“…The molten polymer and polymer solution flowing ability depends strongly on filtration methods . Confinement of AAO porous walls alters the polymer molecular orientation and dynamics of polymer chains , and affects the nanostructure crystallization , glass temperature , polymer tacticity , and electron transportation . Modification of the AAO surface chemistry alters the polymer molecular chain orientation .…”

Section: Introductionmentioning

confidence: 99%

One-dimensional polymer nanofiber arrays with high aspect ratio obtained by thermal nanoimprint method

et al. 2016

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Polymer surface modification that mimicks natural behaviors has been a subject of great interest. Fabrication of polymer nanofiber arrays with various applications has been studied intensively. Avoidance of chemical solvents, reduction of processing time, improvement of the nanofiber size distribution and aspect ratios, and improvement of reproducibility have been sought for industrial value creation. This study examines an alternative fabrication methods for polymer nanofiber arrays using a combination of anodic aluminum oxide (AAO) nanoporous template and thermal nanoimprinting lithography for simple, precise processing. Based on those results, nanofiber arrays were fabricated with 40‐µm‐thick film and 50–100 nm fiber diameter polystyrene (PS) and polypropylene (PP). For this study, 50‐nm diameter PS nanofibers with 50 µm maximum length and a maximum aspect ratio of 1,000 were produced in addition to PP nanofibers having 130 µm maximum length and an aspect ratio of 2,600. The nanofiber lengths were affected considerably by molten polymer flow related to imprint processing conditions, polymer properties, AAO properties, and surface wettability between AAO and molten polymers. Moreover, AAO nanoconfinement demonstrated molecular orientation alignment of polymers that affect thermal properties, crystallinity, and mechanical properties of the obtained polymer nanofiber arrays. POLYM. ENG. SCI., 57:214–223, 2017. © 2016 Society of Plastics Engineers

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Large-Scale Diffusion of Entangled Polymers along Nanochannels

Cited by 37 publications

References 36 publications

Modeling of Entangled Polymer Diffusion in Melts and Nanocomposites: A Review

Modeling of Entangled Polymer Diffusion in Melts and Nanocomposites: A Review

Viscosity and Surface-Promoted Slippage of Thin Polymer Films Supported by a Solid Substrate

One-dimensional polymer nanofiber arrays with high aspect ratio obtained by thermal nanoimprint method

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