Nanoindentation of submicron polymeric coating systems

Geng, Kebin; Yang, Fuqian; Grulke, Eric A.

doi:10.1016/j.msea.2007.06.042

Cited by 26 publications

(17 citation statements)

References 22 publications

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“…An independent effort [15] employed a different analytical approach to account for the substrate effect, which proved valid only for 10 mm thick films and was unable to accurately represent submicron polymer films, attributing the difficulty to ''altered near surface properties'' of the polymer. In contrast to these works, [15][16][17] which assume various models for the substrate effect, we numerically calculate the effect directly and remove it from our experimentally measured data. This coupled approach enables the first quantitative measurements of local elastic properties of polymers in the altered near surface regime.…”

mentioning

confidence: 99%

“…Although time-dependent properties are important in polymers, in this paper, we focus exclusively on elastic response using an accepted approach which extracts properties from the initial elastic unloading segment after a load-hold sequence. [16,19] An underlying assumption in all indentation models based on the Oliver-Pharr approach is that the indented material can be represented by an infinite half-space. As the film thickness decreases, the presence of a mechanically rigid substrate skews the results of the apparent modulus measurements to higher values.…”

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confidence: 99%

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Interfacial and Substrate Effects on Local Elastic Properties of Polymers Using Coupled Experiments and Modeling of Nanoindentation

Watcharotone¹,

Wood²,

Friedrich³

et al. 2011

Adv Eng Mater

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Polymers are used in a wide range of applications for microelectronics, [1] medical engineering, [2] and structural composite engineering [3][4][5][6] where local polymer behavior due to interactions with free surfaces, substrates, or embedded surfaces has a significant impact on polymer response and function. For example, poly(methyl methacrylate) (PMMA) containing very small amounts of functionalized graphenebased sheet (FGS) [3] has shown increased glass transition temperature (T g ) of nearly 30 8C at only 0.05 wt% loading and increased elastic modulus by 33% at 0.01 wt% loading, well above the upper bound of stiffness predicted by traditional composite theory. Remarkable improvements of this magnitude cannot be attributed to a linear property combination of the polymer host and nanoparticles. Thus, interphase -the polymer near nanoparticle-polymer interfaces in which chain mobility and polymer dynamics substantially alter from the neat polymer -plays a critical role in the significant increases in thermodynamic and mechanical properties.Work in the last 15 years has demonstrated in a number of elegant experiments and modeling that T g of polymers can undergo dramatic changes near interfaces, [7][8][9][10] where negative or positive shift of this transition temperature depends upon the nature of the polymer-surface interaction. Thin films on substrates typically show changes in T g for film thicknesses of order 100 nm while for doubly supported thin films the deviation from bulk T g can be sensed up to film thicknesses of 500 nm. [8][9][10] The impact of the surface on the dynamics of the polymer propagates away from the surface significantly due to the macromolecular nature of polymers. Immediately COMMUNICATION [*] L.The mechanical properties of polymers near interfaces are important in a number of different fields. For almost two decades, the local dynamics of thin polymer films have been studied in great detail. However, development of an understanding of local mechanical properties has been hindered by the necessary proximity of stiff substrates: mechanical measurements are confounded by interaction with the substrate, convoluting polymer, and substrate properties. In this paper, local elastic properties of thin polymer films near interfaces are directly probed for the first time via nanoindentation experiments on thin films coupled with finite element modeling. A comprehensive set of experimental and numerical modeling results are presented for poly(methyl methacrylate) (PMMA) revealing separately the effects of substrate and interphase polymer. Results indicate the attractive surface significantly affects the properties up to hundreds of nanometers. This new, direct approach to measure local mechanical properties provides new fundamental understanding of interfacial and small-scale behaviors in polymers and soft matter for application advances in nanocomposites, microelectronics, and biopolymers. 400 wileyonlinelibrary.com ß

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confidence: 99%

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confidence: 99%

Interfacial and Substrate Effects on Local Elastic Properties of Polymers Using Coupled Experiments and Modeling of Nanoindentation

Watcharotone¹,

Wood²,

Friedrich³

et al. 2011

Adv Eng Mater

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“…It is known that during the nanoindentation of a viscoelastic material, the resultant load-displacement plot may exhibit a "nose" (or a "bulge") in the initial unloading segment due to excessive creep. When a "nose" occurs, the resultant contact stiffness will be negative [19][20][21][22]. To reduce the creeping effect (as well as other effects such as instrument drift) on the unloading set of data, a technique called "held-at-the-peak" has been recently adopted for nanoindentation testing of polymers [19][20][21][22].…”

Section: Discussionmentioning

confidence: 99%

High Temperature Nanoindentation of PMR-15 Polyimide

et al. 2009

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This paper presents the high temperature nanoindentation experiments performed on an aerospace polymer resin-PMR-15 polyimide. The sharp-tipped Berkovich nanoindenter equipped with a hot-stage heating system was used. The indentation experiments were performed using the "hold-at-the-peak" method at various indenter holding times and unloading rates. The creep effect was seen to decrease with increasing holding time and/or unloading rate. Procedures used to minimize the creep effect are investigated at both ambient and elevated temperatures so that the correct contact depth (together with modulus and hardness) can be determined from nanoindentation load-depth curve. The temperature dependent mechanical properties of PMR-15 are measured through the current nanoindenter and results are consistent with those obtained from macroscopic tests.

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“…The mechanism of deformation of soft coating on hard substrates [3], hard coatings on soft substrates [3][4][5], soft coating on soft substrates [6,7], or hard coating on hard substrates [8], have been broadly established. Several review articles, have been written on the nanoindentation techniques so far [9][10][11][12][13][14] but none of them focused on hybrid silicone or hybrid epoxy coatings.…”

Section: Introductionmentioning

confidence: 99%

Nanomechanical Analysis of Hybrid Silicones and Hybrid Epoxy Coatings—A Brief Review

Tiwari¹

2012

ACES

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This review article is written on the investigations of nanomechanical properties of coatings by using nanoindentation techniques. The focus is on the studies that were conducted on epoxy polymer, silicones and their hybrid materials. The article describes a large number of developmental studies that are conducted on coatings. Materials properties such as nanoindentation hardness, modulus, scratch, wear and viscoelastic behavior have been described. Moreover, the article summarizes various studies that mention the use of different nanoparticles in coating formulations that could improve the mechanical strength and service life span of the coatings. The mode and mechanism of material's failure has been outlined and discussed.

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Nanoindentation of submicron polymeric coating systems

Cited by 26 publications

References 22 publications

Interfacial and Substrate Effects on Local Elastic Properties of Polymers Using Coupled Experiments and Modeling of Nanoindentation

Interfacial and Substrate Effects on Local Elastic Properties of Polymers Using Coupled Experiments and Modeling of Nanoindentation

High Temperature Nanoindentation of PMR-15 Polyimide

Nanomechanical Analysis of Hybrid Silicones and Hybrid Epoxy Coatings—A Brief Review

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