scholarly journals Buckling of paramagnetic chains in soft gels

Soft Matter ◽  
2016 ◽  
Vol 12 (1) ◽  
pp. 228-237 ◽  
Author(s):  
Shilin Huang ◽  
Giorgio Pessot ◽  
Peet Cremer ◽  
Rudolf Weeber ◽  
Christian Holm ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Polymer Gels ◽  
Paramagnetic Particle ◽  
Soft Polymer ◽  
Soft Gels ◽  
Particle Chains

Paramagnetic particle chains in soft polymer gels can show pronounced buckling deformation under perpendicular external magnetic fields.

COUPLED MAGNETIC FIELD AND VISCOELASTICITY OF FERROGEL

2011 ◽  
Vol 03 (02) ◽  
pp. 259-278 ◽  
Author(s):  
YI HAN ◽  
WEI HONG ◽  
LEANN FAIDLEY
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Material Model ◽  
Finite Element Code ◽  
Equilibrium Thermodynamics ◽  
Numerical Examples ◽  
Rate Dependent ◽  
The Matrix ◽  
Specific Material ◽  
Soft Polymer

Composed of a soft polymer matrix and magnetic filler particles, ferrogel is a smart material responsive to magnetic fields. Due to the viscoelasticity of the matrix, the behaviors of ferrogel are usually rate-dependent. Very few models with coupled magnetic field and viscoelasticity exist in the literature, and even fewer are capable of reliable predictions. Based on the principles of non-equilibrium thermodynamics, a field theory is developed to describe the magneto-viscoelastic property of ferrogel. The theory provides a guideline for experimental characterizations and structural designs of ferrogel-based devices. A specific material model is then selected and the theory is implemented in a finite element code. Through numerical examples, the responses of a ferrogel in uniform and non-uniform magnetic fields are analyzed. The dynamic response of a ferrogel to cyclic magnetic fields is also studied, and the prediction agrees with our experimental results. In the reversible limit, our theory recovers existing models for elastic ferrogel, and is capable of capturing some instability phenomena.

scholarly journals Scattering from dilute ferrofluid suspensions in soft polymer gels

2003 ◽  
Vol 67 (2) ◽  
Author(s):  
Alvaro V. Teixeira ◽  
Isabelle Morfin ◽  
Françoise Ehrburger-Dolle ◽  
Cyrille Rochas ◽  
Erik Geissler ◽  
...  
Keyword(s):  
Polymer Gels ◽  
Soft Polymer

Strong vortical flows generated by the collective motion of magnetic particle chains rotating in a fluid cell

Lab on a Chip ◽  
2015 ◽  
Vol 15 (1) ◽  
pp. 351-360 ◽  
Author(s):  
Yang Gao ◽  
Jasper Beerens ◽  
Alexander van Reenen ◽  
Martien A. Hulsen ◽  
Arthur M. de Jong ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Magnetic Particle ◽  
Collective Motion ◽  
Vortical Flow ◽  
Rotating Magnetic Fields ◽  
Magnetic Microparticles ◽  
Biochemical Assays ◽  
Magnetic Capture ◽  
Particle Chains ◽  
Fluid Cell

Magnetic microparticles suspended in a microfluidic cell exhibit coherent collective motion when actuated with rotating magnetic fields, creating strong vortical flow and enhancing biochemical assays with magnetic capture particles.

Phase sensitive enhancement for biochemical detection using rotating paramagnetic particle chains

2004 ◽  
Vol 96 (11) ◽  
pp. 6831-6838 ◽  
Author(s):  
Anil K. Vuppu ◽  
Antonio A. Garcia ◽  
Mark A. Hayes ◽  
Karl Booksh ◽  
Patrick E. Phelan ◽  
...  
Keyword(s):  
Paramagnetic Particle ◽  
Phase Sensitive ◽  
Biochemical Detection ◽  
Particle Chains

scholarly journals Liquid drops attract or repel by the inverted Cheerios effect

2016 ◽  
Vol 113 (27) ◽  
pp. 7403-7407 ◽  
Author(s):  
Stefan Karpitschka ◽  
Anupam Pandey ◽  
Luuk A. Lubbers ◽  
Joost H. Weijs ◽  
Lorenzo Botto ◽  
...  
Keyword(s):  
Interaction Force ◽  
Solid Particles ◽  
Lateral Interaction ◽  
Range Interaction ◽  
Colloidal Assembly ◽  
Liquid Drops ◽  
Short Range Repulsion ◽  
Soft Polymer ◽  
Soft Gels ◽  
Bulk Elasticity

Solid particles floating at a liquid interface exhibit a long-ranged attraction mediated by surface tension. In the absence of bulk elasticity, this is the dominant lateral interaction of mechanical origin. Here, we show that an analogous long-range interaction occurs between adjacent droplets on solid substrates, which crucially relies on a combination of capillarity and bulk elasticity. We experimentally observe the interaction between droplets on soft gels and provide a theoretical framework that quantitatively predicts the interaction force between the droplets. Remarkably, we find that, although on thick substrates the interaction is purely attractive and leads to drop–drop coalescence, for relatively thin substrates a short-range repulsion occurs, which prevents the two drops from coming into direct contact. This versatile interaction is the liquid-on-solid analog of the “Cheerios effect.” The effect will strongly influence the condensation and coarsening of drops on soft polymer films, and has potential implications for colloidal assembly and mechanobiology.

SOFT GELS WITH ORDERED IRON PARTICLES: FABRICATION AND ELECTRORHEOLOGICAL RESPONSE

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2440-2446 ◽  
Author(s):  
YUXIAN AN ◽  
BO LIU ◽  
MONTGOMERY T. SHAW
Keyword(s):  
Magnetic Field ◽  
Model Systems ◽  
Iron Particles ◽  
Liquid Silicone ◽  
Low Modulus ◽  
Soft Gels ◽  
Er Fluids ◽  
Particle Chains

For a number of years we and others have investigated electrorheological (ER) gel systems comprising low-modulus elastomers mixed with various particles. Unlike ER fluids, the particles in gels do not change relative positions, thus creating model systems that can be used to check equilibrium theories of ER response. To make such materials, a magnetic field was used to align iron particles during the cure of a liquid silicone prepolymer in a sheet mold. Particle chains were made with as little as 0.5% particles, and aligned at angles from 0 to 45° to the normal. The gap between the particles was controlled by swelling the crosslinked material with additional prepolymer. The dependence of the ER effect on particle structuring in these materials was investigated experimentally using rheometry and dielectrometry. Also investigated were the properties of these materials as transducers and actuators.

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