Soft Matter (SOFT MATTER )

Publisher: Royal Society of Chemistry (Great Britain)

Journal description

Soft Matter has a global circulation and interdisciplinary audience with a particular focus on the interface between physics, materials science, biology, chemical engineering and chemistry. Soft Matter appeals to a wide variety of researchers, but particularly to: materials scientists; surface scientists; physicists; biochemists; biological scientists; chemical engineers; physical, organic and theoretical chemists.

Current impact factor: 4.15

Impact Factor Rankings

2015 Impact Factor Available summer 2015
2013 / 2014 Impact Factor 4.151
2012 Impact Factor 3.909
2011 Impact Factor 4.39
2010 Impact Factor 4.457
2009 Impact Factor 4.869
2008 Impact Factor 4.586
2007 Impact Factor 4.703
2006 Impact Factor 4.391
2005 Impact Factor

Impact factor over time

Impact factor
Year

Additional details

5-year impact 4.35
Cited half-life 2.50
Immediacy index 1.01
Eigenfactor 0.07
Article influence 1.33
Website Soft Matter website
Other titles Soft matter
ISSN 1744-683X
OCLC 60788497
Material type Periodical, Internet resource
Document type Journal / Magazine / Newspaper, Internet Resource

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: Electrowetting (EW) offers executive wetting control of conductive liquids on several polymer surfaces. We report a peculiar electrowetting response for aqueous drop on polystyrene (PS) dielectric surface in ambient of silicone oil. After the first direct current (DC) voltage cycle, the droplet failed to regain Young’s angle, yielding contact angle hysteresis, close to a value found in air ambient. We conjecture that the hysteretic EW response appears from in situ surface modification by means of electric field induced water-ion contact with PS surface inducing nano-structuration by electro-hydrodynamic (EHD) instability. The Atomic Force Microscopy confirms the formation of nano-structuration on electrowetted surface. The effects of molecular weight, applied electric field, water conductivity and pH on nano-structuration are studied. Finally, the EW based nano-structuration on PS surface is used for enhanced loading of aqueous dye on hydrophobic surface.
    Soft Matter 02/2015;
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    ABSTRACT: DNA is a powerful tool that can be attached to nano- and micro-objects and direct the self-assembly through base pairing. Since the strategy of DNA programmable nanoparticle self-assembly was first introduced in1996, it remains challenging to use DNA to make powerful diagnostic tools and to make designed materials with novel properties and highly-ordered crystal structures. In this review, we summarize recent experimental and theoretical developments of DNA-programmable self-assembly into three-dimensional (3D) materials. Various types of aggregates and 3D crystal structures obtained from experimental DNA-driven assembly are introduced. Furthermore, theoretical calculations and simulations for DNA -mediated assembly systems are described and we highlight some typical theoretical models for Monte Carlo and Molecular Dynamics simulations.
    Soft Matter 02/2015;
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    ABSTRACT: We study in the melt the linear viscoelastic properties of supramolecular assemblies obtained by adding different amounts of nickel ions to linear entangled poly(ethylene oxide) (PEO) building blocks end-functionalized by a terpyridine group. We first show that the elasticity of these supramolecular assemblies is mainly governed by the entanglement dynamics of the building blocks, while the supramolecular interactions delay or suppress their relaxation. By adjusting the amount of metal ions, the relaxation time as well as the level of the low-frequency plateau of these supramolecular assemblies can be controlled. In particular, the addition of metal ions above the 1 : 2 metal ion/terpyridine stoichiometric ratio allows secondary supramolecular interactions to appear, which are able to link the linear supramolecular assemblies and thus, lead to the reversible gelation of the system. By comparing the rheological behavior of different linear PEO samples, bearing or not functionalized chain-ends, we show that these extra supramolecular bonds are partially due to the association between the excess of metal ions and the oxygen atoms of the PEO chains. We also investigate the possible role played by the terpyridine groups in the formation of these secondary supramolecular interactions.
    Soft Matter 12/2014; 11(4):762-774.
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    ABSTRACT: DNA compaction in a bacterial cell is in part carried out by entropic (depletion) forces induced by "free" proteins or crowding particles in the cytoplasm. Indeed, recent in vitro experiments highlight these effects by showing that they alone can condense the E. coli chromosome to its in vivo size. Using molecular dynamics simulations and a theoretical approach, we study how a flexible chain molecule can be compacted by crowding particles with variable sizes in a (cell-like) cylindrical space. Our results show that with smaller crowding agents the compaction occurs at a lower volume fraction but at a larger concentration such that doubling their size is equivalent to increasing their concentration fourfold. Similarly, the effect of polydispersity can be correctly mimicked by adjusting the size of crowders in a homogeneous system. Under different conditions, however, crowding particles can induce chain adsorption onto the cylinder wall, stretching the chain, which would otherwise remain condensed.
    Soft Matter 12/2014;
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    ABSTRACT: Scientists aspire to understand the underlying physics behind the formation of instabilities in soft matter and how to manipulate them for diverse investigations, while engineers aim to design materials that inhibit or impede the nucleation and growth of these instabilities in critical applications. The present paper reviews the field-induced rotational instabilities which may occur in chiral smectic liquid-crystalline layers when subjected to an asymmetric electric field. Such instabilities destroy the so-named bookshelf geometry (in which the smectic layers are normal to the cell surfaces) and have a detrimental effect on all applications of ferroelectric liquid crystals as optical materials. The transformation of the bookshelf geometry into horizontal chevron structures (in which each layer is in a V-shaped structure), and the reorientation dynamics of these chevrons, are discussed in details with respect to the electric field conditions, the material properties and the boundary conditions. Particular attention is given to the polymer-stabilisation of smectic phases as a way to forbid the occurrence of instabilities and the decline of related electro-optical performances. It is also shown which benefit may be gained from layer instabilities to enhance the alignment of the liquid-crystalline geometry in practical devices, such as optical recording by ferroelectric liquid crystals. Finally, the theoretical background of layer instabilities is given and discussed in relation to the experimental data.
    Soft Matter 12/2014;
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    ABSTRACT: Complete understanding of colloidal assembly is still a goal to be reached. In convective assembly deposition, the concentration gradients developed in evaporating drops or reservoirs are usually significant. However, collective diffusion of charge-stabilized particles has been barely explored. The balance between convective and diffusive flows may dictate the particle dynamics inside evaporating colloidal drops. In this work we performed in situ counting of fluorescent particles in the vicinity of the triple line of evaporating sessile drops by using confocal laser scanning microscopy. We used particles of different sizes, with different charge response over the pH scale and we focused on charged and nearly uncharged particles. Two substrates with different receding contact angles were used. Binary colloidal mixtures were used to illustrate simultaneously the accumulation of particles with two different charge states at the triple line. The deposition rate close to the triple line was different depending on the electric state of the particle, regardless of the substrate used.
    Soft Matter 12/2014;
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    ABSTRACT: A technique for adequate flow control is important in the fields of science and engineering. In this study, we hypothesized that the unrestricted flow control inside a chamber containing 'schools of magnetic particles' might be possible through control of an external magnetic field, biomimicking the flow generated by schools of fish. Microgels based on superparamagnetic iron oxide nanoparticles (SPIONs) and poly(acrylic acid) hydrogels were employed. With an increase in the SPION content, the microgels responded more efficiently to the translational movement of the magnetic field. Rotational movement was more efficiently achieved with anisotropic distribution of SPIONs inside microgels, which was induced by applying a magnetic field immediately prior to crosslinking. The systems of the anisotropic microgels successfully provided microflow for effective mixing in a capillary. This biomimetic flow control may be useful for the control of fluid systems of any micro- or nano-size and any shape, regardless of the tortuosity.
    Soft Matter 12/2014; 11(5).
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    ABSTRACT: Intense shear can lead to aggregation of colloids that are highly stable at rest. The aggregation process typically has an induction time, and then becomes explosive, leading to rapid phase transitions. We study the phase evolution during shear-driven aggregation in a short microchannel (MC) under intense shear for a colloid with a high interaction energy barrier that ensures high stability of particles and clusters before and after intense shear. The short residence time allows us to snapshot the phase evolution by repeatedly cycling the colloid in the MC. It is found that, depending on the particle concentration, in addition to a fluid of clusters and a solid-like gel, there is another solid-like state between them: Wigner glass of clusters. Their transitions occur over a large range of particle concentrations. We have proposed a phase diagram that describes how the transitions of the three phases evolve in the aggregation steady state in the colloidal interaction vs. particle concentration plane.
    Soft Matter 12/2014;
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    ABSTRACT: NMR measurements on a selectively deuterated liquid crystal dimer CB-C9-CB, exhibiting two nematic phases, show that the molecules in the lower temperature nematic phase, NX, experience a chiral environment and are ordered about a uniformly oriented director throughout the macroscopic sample. The results are contrasted with previous interpretations that suggested a twist-bend spatial variation of the director. A structural picture is proposed wherein the molecules are packed into highly correlated chiral assemblies.
    Soft Matter 12/2014;
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    ABSTRACT: A Velcro-like poly(ethylene glycol) (PEG) interface was prepared in order to control the friction dynamics of material surfaces. Graft- and loop-type PEGs were formed on mirror-polished Ti surfaces using an electrodeposition method with mono- and di-amine functionalized PEGs. The friction dynamics of various combinations of PEG surfaces (i.e., graft-on-graft, loop-on-loop, graft-on-loop, and loop-on-graft) were investigated by friction testing. Here, only the Velcro-like combinations (graft-on-loop and loop-on-graft) exhibited a reversible friction behavior (i.e., resetting the kinetic friction coefficient and the reappearance of the maximum static friction coefficient) during the friction tests. The same tendency was observed when the molecular weights of loop- and graft-type PEGs were tested at 1 k and 10 k, respectively. This indicates that a Velcro-like friction behavior could be induced by simply changing the conformation of PEGs, which suggests a novel concept of altering polymer surfaces for the effective control of friction dynamics.
    Soft Matter 12/2014;
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    ABSTRACT: The Pickering emulsion process is an important and interesting way of forming hybrid soft matter particles stabilized by solid particles as surfactants instead of the extensive use of conventionally available organic surfactant molecules. This Highlight briefly reviews stimuli-responsive polymer/inorganic hybrid materials fabricated by Pickering emulsion polymerization along with the rheological characteristics of their electrorheological and magnetorheological smart fluids under electric and magnetic fields, respectively.
    Soft Matter 12/2014;
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    ABSTRACT: The compartmentalization of microgels is a challenging task for synthetic polymer chemistry. Although the complexation with low molecular weight compounds or the use of microfluidic techniques offer attractive possibilities for other length scales, it is difficult to implement compartments in the mesoscale range of 10-100 nm. Herein we show how simple blending of reactive prepolymers is suitable to design new microgel morphologies with tailored compartments. We use poly(EEGE)-block-poly(AGE) as crosslinkable, pro-hydrophilic prepolymer in blends with varying amounts of crosslinkable, yet hydrophobic poly(THF-stat-AllylEHO) or inert and hydrophobic polystyrene, and crosslink the allyl functional prepolymer(s) in a thiol-ene click-type reaction after miniemulsification. Our strategy shows how arrested versus free nanophase separation can be used to control easily the morphology and polarity of microgel particles.
    Soft Matter 12/2014;
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    ABSTRACT: Holographic video microscopy offers valuable and previously unavailable insights into the progress of colloidal synthesis by providing measurements of the size and refractive index of individual colloidal particles in the dispersion. These measurements are precise enough to track subtle changes in particles' properties and rapid enough for real-time process control. We demonstrate this technique by applying it to the synthesis of monodisperse samples of crosslinked polydimethysiloxane (PDMS) spheres. The measured time dependence of these spheres' most probable radius is consistent with the LaMer model for colloidal growth. The joint distribution of size and refractive index, however, also reveals a small proportion of undersize, lower-density spheres. Trends in the distribution's time evolution offer insights into their origin. Applied over longer time periods, holographic characterization also tracks how the newly-synthesized spheres age, and illuminates the aging mechanism.
    Soft Matter 12/2014;
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    ABSTRACT: High resolution structure is presented for the ripple (Pβ') phase of the phospholipid dimyristoylphosphatidylcholine. Low angle X-ray scattering from oriented samples yielded 57 orders, more than twice as many as recorded previously. The determined electron density map has a sawtooth profile similar to the result from lower resolution data, but the features are sharper allowing better estimates for the modulated bilayer profile and the distribution of headgroups along the aqueous interface. Analysis of high resolution wide angle X-ray data shows that the hydrocarbon chains in the longer, major side of the asymmetric sawtooth are packed similarly to the LβF gel phase, with chains in both monolayers coupled and tilted by 18° in the same direction. The absence of Bragg rods that could be associated with the minor side is consistent with disordered chains, as often suggested in the literature. However, the new high resolution bilayer profile strongly suggests that the chains in the two monolayers in the minor side and the curved region are not in registry. This staggered monolayer modulated melting suggests a direction for improving theories of the ripple phase.
    Soft Matter 12/2014;
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    ABSTRACT: Most macroscopic machines rely on wheels and gears. Yet, rigid gears are entirely impractical on the nano-scale. Here we propose a more useful method to couple any rotary engine to any other mechanical elements on the nano- and micro-scale. We argue that a rotary molecular motor attached to an entangled polymer energy storage unit, which together form what we call the "tanglotron" device, is a viable concept that can be experimentally implemented. We derive the torque-entanglement relationship for a tanglotron (its "equation of state") and show that it can be understood by simple statistical mechanics arguments. We find that a typical entanglement at low packing density costs around 6kT. In the high entanglement regime, the free energy diverges logarithmically close to a maximal geometric packing density. We outline several promising applications of the tanglotron idea and conclude that the transmission, storage and back-conversion of topological entanglement energy are not only physically feasible but also practical for a number of reasons.
    Soft Matter 12/2014;
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    ABSTRACT: We report the formation of solvent-mediated gels as well as their hierarchical structures and rheological properties. The gelator used is a hybrid with a molecular structure of cholesterol-polyoxometalate-cholesterol, in which the cholesterol dissolves well in toluene and N,N-dimethylformamide (DMF), whereas the polyoxometalate cluster dissolves only in DMF. These solubility differences enable the gelator to form thermally reversible supramolecular organogels by mixing solvents of toluene and DMF when the volume fraction, ftol, of toluene is larger than 85.7 v/v%. We found a V-shaped correlation between the gelation times, tgel and ftol: tgel decreases from 1300 min to 2 min when ftol increases from 85.7 v/v% to 90.0 v/v%. It then increases from 2 min to 5800 min when ftol further increases from 90.0 v/v% to 100.0 v/v%. We observed ribbon-like self-assembled structures in the gels as well as a structural evolution from rigid and straight ribbons to twistable ones from ftol = 85.7 v/v% to ftol = 100.0 v/v%. These ribbons constitute two three-dimensional (3D) gel networks: one is constructed via physical connection of the rigid and straight ribbon, and the other is built up from ribbons splitting and intertwining. The latter has a better 3D gel network that offers improved rheological properties. Fundamentally, this solvent-mediated approach regulates the balance between solubility and insolubility of this gelator in the mixing solvents. It also provides a new method for the preparation of organogels.
    Soft Matter 12/2014; 11(4).
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    ABSTRACT: Atomistic molecular dynamic simulations have been performed for the non-ionic chromonic liquid crystal 2,3,6,7,10,11-hexa-(1,4,7-trioxa-octyl)-triphenylene (TP6EO2M) in aqueous solution. TP6EO2M molecules consist of a central poly-aromatic core (a triphenylene ring) functionalized by six hydrophilic ethyleneoxy (EO) chains, and have a strong tendency to aggregate face-to-face into stacks even in very dilute solution. We have studied self-assembly of the molecules in the low concentration range corresponding to an isotropic solution of aggregates, using two force fields GAFF and OPLS. Our results reveal that the GAFF force field, even though it was successfully used previously for modelling of ionic chromonics, overestimates the attraction of TP6EO2M molecules in water. This results in an aggregation free energy which is too high, a reduced hydration of EO chains and, therefore, molecular self-assembly into compact disordered clusters instead of stacks. In contrast, use of the OPLS force field, leads to self-assembly into ordered stacks in agreement with earlier experimental studies of triphenylene-based chromonics. The free energy of association follows a "quasi-isodesmic" pattern, where the binding free energy of two molecules to form a dimer is of the order of 2.5 RT larger than the corresponding energy of addition of a molecule into a stack. The obtained value for the binding free energy, ΔG = -12 RT, is found to be in line with the published values for typical ionic chromonics (-7 to -12 RT), and agrees reasonably well with the experimental results for this system. The calculated interlayer distance between the molecules in a stack is 0.37 nm, which is at the top of the range found for typical chromonics (0.33-0.37 nm). We suggest that the relatively large layer spacing can be attributed to the repulsion between EO side chains.
    Soft Matter 12/2014;