ToF-SIMS Depth Profiling to Measure Nanoparticle and Polymer Diffusion in Polymer Melts

Wang, Kaitlin; Composto, Russell J.; Winey, Karen I.

doi:10.1021/acs.macromol.3c00033

Cited by 7 publications

(11 citation statements)

References 38 publications

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“…If an adsorbed polymer layer of the order of R g was added to the NP radius, then the derived diffusion coefficient agreed with SE predictions . These results were recently reproduced using time-of-flight secondary ion mass spectroscopy . Another recent study on attractive PNC systems has shown a similar suppression in diffusion (relative to SE predictions), in unentangled polymers, through dynamic light scattering measurements.…”

Section: Introductionsupporting

confidence: 58%

Nanoparticle Diffusion in Miscible Polymer Nanocomposite Melts

et al. 2023

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X-ray photon correlation spectroscopy measurements were used to quantify the dynamics of bare and bimodal grafted silica nanoparticles mixed with PEO melts of different molecular weights. In dilute polymer nanocomposite (PNC) samples, we find diffusive NP behavior as described by the Stokes–Einstein relationship so long as the adsorbed PEO polymer layer is taken into account in determining both the effective NP size and its role on composite viscosity. The size of this bound layer was found to be approximately 2R g, where R g is the chain radius of gyration. We also expanded our system to investigate how the dynamics of grafted NPs differ from bare NPs with an adsorbed layer. We showed that the dynamics again can be determined by an effective NP radius at a scale smaller than the effective interparticle spacing; however, at larger length scales, the morphology and grafting parameters play a major role in the system dynamics. These results allow us to quantify NP ordering driven by polymer crystallization. It has previously been speculated that behavior is controlled by the relative ratio of time scale of crystal growth and the diffusive time scale of the NPs, a Peclet number. When the former time scale is longer, then the NPs are expected to be segregated into the interlamellar amorphous zones, while the NPs are too slow to be reorganized in the opposite case. We show here that this conjecture is quantitatively correct and the demarcation in behavior occurs for Pe = 1. Thus, we provide a way to estimate a critical spherulite growth rate for any semicrystalline PNC, at which a given NP can be ordered. Together, the results of this study permit us to tunably design PNCs through directed dispersion of NPs in a polymer matrix.

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Section: Introductionsupporting

confidence: 58%

Nanoparticle Diffusion in Miscible Polymer Nanocomposite Melts

et al. 2023

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“…Dynamic SIMS is a well-established technique for measuring polymer interfaces and more recently applied to particle diffusion. ,– …”

Section: Methodsmentioning

confidence: 99%

Determination of the Interfacial Energy between Graphene Nanoplatelets and Deuterated or Hydrogenated Polystyrene

Lin,

Liu,

Onghai

et al. 2023

Macromolecules

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The tracer diffusion coefficients of various graphene nanoplatelet-polystyrene (GNP-PS) systems were determined by using dynamic secondary ion mass spectrometry, which provided insights into the interactions within the polymer nanocomposite system. Bilayer films, where one contained trace amounts of deuterated polystyrene (dPS), were produced, and the interdiffusion was measured by detecting the position of the dPS interface. GNPs were placed in both or only one of the two layers. The diffusion coefficient was decreased when GNPs were present in both layers as compared to the samples without GNP, indicating an attractive interaction between GNP and polystyrene. Surprisingly, the coefficient increased relative to the control when GNPs were present only in the PS containing layer, whereas it decreased most strongly when GNP and dPS were present only in the same layer, indicating that an additional preference existed for GNPs and dPS. A significant difference in interfacial energies was measured using contact angle goniometry of PS or dPS droplets on flat GNP layers, confirming the preferential interaction. DFT calculations were used to calculate the interfacial interaction between GNP and dPS or PS, and they showed an attractive potential which was maximal when the PS rings were conformal with the GNP structure. The differential energy between PS and dPS at the GNP interface was in excellent agreement with the measured value. In contrast, contact angle goniometry indicated that the interaction between GNP and poly(methyl methacrylate) (PMMA) was unfavorable, and no difference in interfacial energy between dPMMA and PMMA was observed. Therefore, these techniques can provide a means for determining the relative affinity between GNP and different polymer hosts, which can be an important consideration in the mechanics and adhesion properties of the compounds.

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“…Specific solution concentrations and spin-coating conditions for each layer are listed in Tables S2 and S3. Similar to our previous report, each PNC layer was transferred to a P2VP base layer by etching the spun coat PNC layer off the SiO 2 wafer using a 20 wt % NaOH solution, resulting in a floating PNC film that can be rinsed with DI water and stacked on top of the P2VP base layer. The top P2VP layer was transferred to the bilayer similarly.…”

Section: Introductionmentioning

confidence: 94%

“…Building upon our earlier study, we crafted trilayer samples composed of a thin PNC layer placed between two thick P2VP matrix layers. Upon annealing, NPs diffuse into the homopolymer layers and we measure the NP tracer diffusion coefficient, D NP .…”

Section: Introductionmentioning

confidence: 99%

Vehicular and Core–Shell Nanoparticle Diffusion in Attractive Entangled Polymer Melts

Wang,

Winey

2024

Macromolecules

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This work studies nanoparticle (NP) diffusion in attractive polymer melts and reveals two distinct dynamic modes: vehicular and core−shell. By diffusing alumina NPs (R NP = 6.5 nm) and silica NPs (R NP = 8.3 and 26.2 nm) into poly(2-vinylpyridine) melts of various molecular weights (14−1220 kDa), we examine the impact of the R NP , polymer size (R g ), and surface chemistry on NP diffusion. Using time-of-flight secondary ion mass spectrometry and trilayer samples, we measure cross-sectional nanoparticle concentration profiles as a function of the annealing time and extract nanoparticle diffusion coefficients. Both small and large silica NPs (R g /R NP = 0.12−3.6) display core−shell behavior, while alumina NPs (R g /R NP = 0.50−4.6) diverge sharply with increasing polymer molecular weight, aligning with theoretically predicted vehicular diffusion. The transition from core− shell to vehicular diffusion is the result of both increasing molecular weight and weaker NP/polymer attractions and facilitates an estimate of the monomer desorption time.

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ToF-SIMS Depth Profiling to Measure Nanoparticle and Polymer Diffusion in Polymer Melts

Cited by 7 publications

References 38 publications

Nanoparticle Diffusion in Miscible Polymer Nanocomposite Melts

Nanoparticle Diffusion in Miscible Polymer Nanocomposite Melts

Determination of the Interfacial Energy between Graphene Nanoplatelets and Deuterated or Hydrogenated Polystyrene

Vehicular and Core–Shell Nanoparticle Diffusion in Attractive Entangled Polymer Melts

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