Forces between Polystyrene Particles in Water Using the AFM:  Pull-Off Force vs Particle Size

Hodges, Chris; Cleaver, J.A.S.; Ghadiri, Mojtaba; Jones, Roger; Pollock, H. M.

doi:10.1021/la025604q

Cited by 54 publications

(50 citation statements)

References 29 publications

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“…Obtained floc strength was 2 nN in average and did not depend on floc size. The values of floc strength of this study were also compared with those of previous studies [11,13,14,17,18].…”

Section: Introductionmentioning

confidence: 89%

Breakup and strength of polystyrene latex flocs subjected to a converging flow

Kobayashi

2004

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Breakup of flocs (aggregates of colloidal particles) in converging flows is encountered in many industrial processes such as filtration, pipetting for sampling of flocs, and mechanical dispersion. The experiment of breakup of flocs by a converging flow opens the possibility to obtain the strength of floc against breakup. The quantity is crucial for controlling flocculator in water treatments and predicting transport of colloidal particles in aqueous environments. Therefore, the mechanism of disaggregation of flocs subjected to a converging flow is emerging as an interesting theme from engineering and scientific points of view. Recently, Blaser evaluated the hydrodynamic disrupting force on a floc in an axisymmetrical straining flow. In the present study, to confirm the validity of the ellipsoidal model proposed by Blaser and to obtain the strength of latex flocs in a simple electrolyte solution, polystyrene sulfate latex (PSL) flocs formed in a simple KCl solution were disrupted by a converging flow of the solution. Experimental data of relationships between floc size and volumetric flow rate were analyzed by assuming flocs hydrodynamically behave like solid ellipsoids to evaluate strength of flocs. The obtained floc strength was 2 nN in average and did not depend on floc size. When the values of floc strength of this study were compared with those of previous researches, they were found to be 1-2 orders smaller than strengths of flocs formed by the addition of polymer flocculants and/or precipitated ferric or aluminum hydroxide coagulants evaluated by similar methods. This result is reasonable because flocculants and coagulants are usually used to increase floc strength in water and wastewater treatments. The value of obtained floc strength was also comparable to the pull-off force between latex particles in water by means of colloid probe atomic force microscopy (AFM) by Hodges et al. However, the obtained floc strength was 1-2 orders of magnitude smaller than the pull-off force between latex particles as found with colloid probe AFM by Li et al.

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“…Obtained floc strength was 2 nN in average and did not depend on floc size. The values of floc strength of this study were also compared with those of previous studies [11,13,14,17,18].…”

Section: Introductionmentioning

confidence: 89%

Breakup and strength of polystyrene latex flocs subjected to a converging flow

Kobayashi

2004

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…13,14 The modeling of pull-off force is mainly based on two different approaches based on the surface energies on the contact, [15][16][17][18] or on the integration of the van der Waals forces between objects [19][20][21][22] and on some hybrid approaches between both. 23,24 The adhesion force reduction was already obtained in liquid and dry medium by surface structuring [24][25][26] or chemical functionalisation. 9,[27][28][29] The last technique allows to switch the force from attractive to repulsive by pH solution modification and improves the micro-object manipulation.…”

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confidence: 99%

Adhesion Control for Micro- and Nanomanipulation

et al. 2011

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The adhesion between a micro/nano-object and a micro-gripper end-effector is an important problem in micromanipulation. Cancelling or reduction this force is a great challenge.This force is directly linked to the surface chemical structure of the object and the gripper. We propose to predict this force between a structuring surface and a micro-object with a multisphere van der Waals force model. The surface was structured by polystyrene latex particles (PS particles) with radii from 35 to 2000 nm. The model was compared with experimental pulloff force measurement performed by AFM with different natures of spheres materials glued on the tipless. A wide range of applications, in the field of telecommunications, bioengineering, and more generaly speaking MEMS can be envisaged for these substrates. † FEMTO-ST Institute ‡ IEMM ¶ EMPA

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“…It has been reported that the attractive force of a polystyrene particle with a solid surface and the force between silica particles covered with CTAB layers could be measured by AFM. [22][23][24][25] In comparison with AFM method, which has the sensitivity of 0.1 nN, our method proved to have a higher sensitivity, of pN order, in the measurement of adsorption force. DLVO theory explained the interaction force between two surfaces as the combination of van der Waals force and the electrostatic repulsion force.…”

Section: Resultsmentioning

confidence: 89%

Electromagnetophoretic Measurements of Adsorption Forces of Polystyrene Microparticles on Silica Surfaces in Surfactant Solutions

Iiguni¹,

Watarai²

2006

Bulletin of the Chemical Society of Japan

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An electromagnetophoretic force has been applied for the measurement of the adsorption force of a single polystyrene particle to a silica surface in electrolyte solutions. By the electromagnetophoretic buoyancy, polystyrene microparticles in a fused-silica capillary were made to migrate perpendicular to the wall of the capillary. A switching of the current direction and a gradual increase of the current under a homogeneous magnetic field of 10 T could desorb the single particle from the wall and allowed us to measure the adsorption force from the desorbing current with a sensitivity of pN. By this method, the adsorption forces of polystyrene particles on a bare surface and on a squalane-coated fused-silica surface were measured in the absence and the presence of surfactants such as Triton X-100, cetyltrimethylammonium bromide, and sodium dodecyl sulfate. The observed adsorption forces showed that the roles of the surfactants included not only the reduction of the adsorption force as a spacer, but also the production of a characteristic force due mainly to electrostatic interaction.

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Forces between Polystyrene Particles in Water Using the AFM: Pull-Off Force vs Particle Size

Cited by 54 publications

References 29 publications

Breakup and strength of polystyrene latex flocs subjected to a converging flow

Breakup and strength of polystyrene latex flocs subjected to a converging flow

Adhesion Control for Micro- and Nanomanipulation

Electromagnetophoretic Measurements of Adsorption Forces of Polystyrene Microparticles on Silica Surfaces in Surfactant Solutions

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