Viscoelasticity in Nanoscale Friction on Thin Polymer Films

Haugstad, Greg; Hammerschmidt, Jon A.; Gladfelter, Wayne L.

doi:10.1021/bk-2001-0781.ch015

Cited by 4 publications

(2 citation statements)

References 3 publications

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“…In the past few years, atomic force microscopy (AFM) has been used to image film morphologies and probe surface properties, such as ligand and receptor interactions and viscoelasticity (1,18). AFM provides three-dimensional images of a surface ultrastructure with molecular or near-molecular resolution under physiological conditions and with minimal sample preparation.…”

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confidence: 99%

Biofilm Cohesiveness Measurement Using a Novel Atomic Force Microscopy Methodology

Ahimou¹,

Semmens²,

Novak³

et al. 2007

Appl Environ Microbiol

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113

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Biofilms can be undesirable, as in those covering medical implants, and beneficial, such as when they are used for waste treatment. Because cohesive strength is a primary factor affecting the balance between growth and detachment, its quantification is essential in understanding, predicting, and modeling biofilm development. In this study, we developed a novel atomic force microscopy (AFM) method for reproducibly measuring, in situ, the cohesive energy levels of moist 1-day biofilms. The biofilm was grown from an undefined mixed culture taken from activated sludge. The volume of biofilm displaced and the corresponding frictional energy dissipated were determined as a function of biofilm depth, resulting in the calculation of the cohesive energy. Our results showed that cohesive energy increased with biofilm depth, from 0.10 ؎ 0.07 nJ/m 3 to 2.05 ؎ 0.62 nJ/m 3 . This observation was reproducible, with four different biofilms showing the same behavior. Cohesive energy also increased from 0.10 ؎ 0.07 nJ/m 3 to 1.98 ؎ 0.34 nJ/m 3 when calcium (10 mM) was added to the reactor during biofilm cultivation. These results agree with previous reports on calcium increasing the cohesiveness of biofilms. This AFM-based technique can be performed with available off-the-shelf instrumentation. It could therefore be widely used to examine biofilm cohesion under a variety of conditions.It is essential to understand biofilm stability to both encourage biofilm maintenance in some applications, such as waste treatment, and effectively remove undesired biofilm in others, as in biofilms covering medical implants. Biofilm detachment is one of the critical factors that balance growth and plays a role in the development of biofilm spatial heterogeneity. While factors responsible for biofilm growth are well studied (16,29,39,42,43), those controlling the detachment process are not clearly understood (28,36,38). As a consequence, a good understanding of the relationships between operating conditions and biofilm cohesion is lacking. The cohesive strength of the biofilm is influenced by extracellular polymeric substances (EPS) and specific compounds, such as calcium, which fill the space between microbial cells and bind cells together (23,30). Understanding the cohesive interactions in the biofilm matrix under a variety of conditions could lead to the design of new strategies for controlling biofilm development based on disrupting or protecting the matrix holding the biofilm together.Because cohesive strength is a primary factor affecting biofilm sloughing, its quantification is essential in understanding detachment. A few methods based on the use of custom devices have been proposed to investigate biofilm cohesive strength. Poppele and Hozalski (31) measured the tensile strength levels of biofilms from activated sludge by using a micromechanical device based on the deflection of a glass micropipette separating a microbial aggregate held by suction. Körstgens et al. (22) used a uniaxial compression measurement device to determine the yield st...

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mentioning

confidence: 99%

Biofilm Cohesiveness Measurement Using a Novel Atomic Force Microscopy Methodology

Ahimou¹,

Semmens²,

Novak³

et al. 2007

Appl Environ Microbiol

Self Cite

113

View full text Add to dashboard Cite

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“…Both for PMMA and PS, frictional forces increased significantly near the glass transition temperature, due to the variation in viscoelastic loss near this temperature. Time-temperature superposition of friction on a PMMA surface has also been studied [122]. Using a temperature-controlled AFM, authors were able to perform friction tests at different velocities for various temperatures.…”

Section: Nanoscale Friction On Viscoelastic Surfacesmentioning

confidence: 99%

Multiscale Frictional Properties of Cotton Fibers: A Review

Hosseinali

Thomasson

2018

Fibers

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This review discusses the important concept of cotton fiber friction at both the macro-and nanoscale. First, the technological importance of fiber friction and its role in fiber breakage during fiber processing is discussed. Next, previous studies on frictional properties of cotton fibers are reviewed and different experimental procedures to measure friction between fibers or against another surface are evaluated. Friction models developed to explain friction process during various experimental procedures are considered and their limitations are discussed. Since interpretation of friction processes at the macroscale can be challenging (mainly due to difficulties in analyzing the multiple asperities in contact), a separate section is devoted to surveying studies on the emerging field of single-asperity friction experiments with atomic force microscope (AFM). Special attention is given to studies on nanoscale frictional characteristics of rough viscoelastic surfaces (e.g., plant cuticular biopolymers and cotton fibers). Due to the close relationship between friction and adhesion hysteresis at the nanoscale, adhesion studies with AFM on viscoelastic surfaces are also reviewed. Lastly, recommendations are made for future research in the field of frictional properties of cotton fibers.

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Atomic Force Microscopy of Polymers: Imaging, Probing and Lithography

Sheiko¹,

Möller²

2007

Macromolecular Engineering

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Viscoelasticity in Nanoscale Friction on Thin Polymer Films

Cited by 4 publications

References 3 publications

Biofilm Cohesiveness Measurement Using a Novel Atomic Force Microscopy Methodology

Biofilm Cohesiveness Measurement Using a Novel Atomic Force Microscopy Methodology

Multiscale Frictional Properties of Cotton Fibers: A Review

Atomic Force Microscopy of Polymers: Imaging, Probing and Lithography

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