Themed collection Soft Matter Emerging Investigators Series
A new order of liquids: polar order in nematic liquid crystals
Given the widespread adoption of display technology based on nematic liquid crystals, the discovery of new nematic phases at thermodynamic equilibrium, although extremely rare, generates much excitement.
Worm blobs as entangled living polymers: from topological active matter to flexible soft robot collectives
Living worms form “blobs,” active entangled physical structures with emergent properties. We show how these worms provide a fascinating platform to study active polymer physics.
Fluid manipulation via multifunctional lubricant infused slippery surfaces: principle, design and applications
Water-repellent interfaces with high performance have emerged as an indispensable platform for developing advanced materials and devices.
Solvent-assisted self-assembly of block copolymer thin films
Solvent-assisted block copolymer self-assembly is a compelling method for advancing practical applications of these materials due to the exceptional level of the control of BCP morphology and significant acceleration of ordering kinetics.
Quantifying the trade-off between stiffness and permeability in hydrogels
Hydrogels have a distinct trade-off between mechanical stiffness and water permeability due to the spacing of polymer strands.
A simple simulation-derived descriptor for the deposition of polymer-wrapped carbon nanotubes on functionalized substrates
Analysis of solvent structure obtained from all-atom molecular dynamics simulations reveals a descriptor that predicts the experimental deposition of polymer-wrapped carbon nanotubes.
Repulsive torques alone trigger crystallization of constant speed active particles
Active particles which repel each other through torques crystallize without reducing their intrinsic speed.
Temperature-dependent reentrant phase transition of RNA–polycation mixtures
In this letter, we report that RNA–polycation mixtures display a temperature-controlled dual-response phase behavior with concurrent UCST and LCST transitions.
Elasticity tunes mechanical stress localization around active topological defects
Topological defects play diverse roles in biology. We find that tuning the passive elasticity substantially changes the intensity and extent of stresses, and in active systems can invert the defect motion and stress pattern.
Branched copolymer surfactants impart thermoreversible gelation to LAPONITE® gels
Composite solutions of LAPONITE® and branched copolymer surfactants give thermoreversible sol–gel transitions due to nanostructural assembly processes.
Soft Matter Emerging Investigators Series: Exploring how cation entropy influences electric double layer formation and electrochemical reactivity
Stimuli-directed selective detection of Cu2+ and Cr2O72− ions using a pH-responsive chitosan-poly(aminoamide) fluorescent microgel in aqueous media
In this work, the preparation of a pH-responsive fluorescent microgel, (NANO-PAMAM-CHT), is presented for the selective detection of Cu2+ and Cr2O72− ions.
Hydrophobically modified complex coacervates for designing aqueous pressure-sensitive adhesives
The rheology of complex coacervates can be elegantly tuned via the design and control of specific non-covalent hydrophobic interactions between the complexed polymer chains.
Geometric learning of knot topology
Unambiguous knot classification is a long-standing problem. In this paper, the authors use Machine Learning to classify all knots up to 10 crossings with more than 95% accuracy and also to distinguish knots with multiple identical knot polynomials.
Rate-dependent stress-order coupling in main-chain liquid crystal elastomers
This study reports rate-dependent measurements and relaxation of stress, director rotation, and shear strain in main-chain nematic LCEs subjected to uniaxial tension with various initial directors, which is further explained by an analytical model.
Effects of crowding on the diffusivity of membrane adhered particles
We investigate changes in the diffusivity and rheology of particles tethered to a lipid bilayer as they become highly crowded.
The cohesive properties and pyrolysis mechanism of an aprotic ionic liquid tetrabutylammonium bis(trifluoromethanesulfonyl)imide
This work proposed a novel method to calculate the wide-temperature-range cohesive properties of organic salts in both the liquid and solid states, and first calculate the charge separation distance in the single ion pair of the vapor.
Capillary detachment of a microparticle from a liquid–liquid interface
Microparticles at a liquid–liquid interface are common in many material systems, from Pickering emulsions to capillary suspensions. Confocal and colloidal probe microscopy are combined to measure meniscus shape and detachment forces.
Effect of small amounts of akaganeite (β-FeOOH) nanorods on the gelation, phase behaviour and injectability of thermoresponsive Pluronic F127
Composite hydrogels containing small amounts of paramagnetic akaganeite (β-FeOOH) nanorods in PF127 triblock copolymer show enhanced thermal stability and injectability which could find applications in tissue engineering and drug delivery.
Soft, flexible pressure sensors for pressure monitoring under large hydrostatic pressure and harsh ocean environments
A soft, flexible pressure sensor is developed to measure hydrostatic pressure in the ocean environment, which can be potentially integrated with many platforms including diver equipment and marine animal tags for real-time pressure monitoring.
Crossover behavior in stress relaxations of poroelastic and viscoelastic dominant hydrogels
AFM measurement reveals that two distinct mechanisms determine the crossover phenomenon in the stress relaxation of hydrogels. This contributes to a better understanding of similar mechanical behaviors of cells and tissues.
Influence of surfactant on glass transition temperature of poly(lactic-co-glycolic acid) nanoparticles
Presented is an experimental study of PVA and DMAB stabilized PLGA particles and the measurement of their Tg's with mDSC.
Microfluidic nanobubbles: observations of a sudden contraction of microbubbles into nanobubbles
Utilizing a microfluidic flow-focusing chip to generate monodisperse bulk nanaobubbles. We make the surprising observation of a critical microbubble diameter above and below which the scale of bubble shrinkage dramatically changes.
Investigating the cut-off effect of n-alcohols on lipid movement: a biophysical study
Cellular membranes are responsible for absorbing the effects of external perturbants for the cell's survival.
Magnetic field enabled in situ control over the structure and dynamics of colloids interacting via SALR potentials
A model system of tunable, competing short-range attraction (SA) and long-range repulsion (LR) among colloidal particles is developed which encompasses a diverse range of assembled states, including fractal clusters and a Wigner glass state.
Investigating structure and dynamics of unentangled poly(dimethyl-co-diphenyl)siloxane via molecular dynamics simulation
Poly(dimethyl-co-diphenyl)siloxane has improved mechanical properties compared with polydimethylsiloxane. We used atomistic molecular dynamics simulation to investigate how the diphenyl contents slow down the relaxation dynamics of the copolymers.
A coarse-grained simulation model for colloidal self-assembly via explicit mobile binders
Developing a model for assembly of colloids with mobile binding sites, we probe the physics of assembly of adhesion patches between particles. We find design rules for assembly of low valence chains, and also study the folding behavior of these ‘colloidomers’.
Deforming active droplets in viscoelastic solutions
In a viscoelastic environment, characterized by Deborah number (De), active droplets get deformed and perform zig-zag motion. This unique motion is inextricably linked to the swimming mode employed by them.
Dynamic shapes of floppy vesicles enclosing active Brownian particles with membrane adhesion
The combined effect of self-propulsion and membrane adhesion of colloidal particles in a fluid vesicle is studied numerically. Novel ring-, sheet-, and branched-polymer-like particle arrangements are obtained.
Prediction of zwitterion hydration and ion association properties using machine learning
Hydration and ion association data for a library of zwitterions was produced by molecular dynamics simulations. Machine learning was applied to reveal how chemical design influences target properties.
Torsion-induced stick-slip phenomena in the delamination of soft adhesives
Propagation of stick-slip waves along the circumference of soft adhesive cylinders under combined torsion and compression is shown experimentally and explained by a theoretical model.
Preparation of polymer nanoparticle-based complex coacervate hydrogels using polymerisation-induced self-assembly derived nanogels
pH-responsive nanogels synthesised by reversible addition-fragmentation chain-transfer mediated polymerisation-induced self-assembly were used to prepare shear-thinning polymer nanoparticle-based complex coacervate hydrogels.
Boundary design regulates the diffusion of active matter in heterogeneous environments
The transport of self-propelled particles in porous media is sensitive to boundary design; effective temperature corrections to Brownian models tend to overestimate the diffusivity of active swimmers after normalizing by their bulk self-diffusivity.
Diffusiophoresis of a spherical particle in porous media
We develop a mathematical model that can predict the diffusiophoretic motion of a charged colloidal particle driven by a binary monovalent electrolyte concentration gradient in porous media.
Long term phase separation dynamics in liquid crystal-enriched microdroplets obtained from binary fluid mixtures
Herein, we compare the phase separation dynamics of binary liquid–liquid crystal mixtures in droplet-based confinement to behaviour in the bulk using experiments, computer simulations and thermodynamic considerations.
Two-dimensional diffusiophoretic colloidal banding: optimizing the spatial and temporal design of solute sinks and sources
We numerically explore diffusiophoretic banding of colloidal particles in two dimensions by spatio-temporally designing solute sources and sinks. We discover an optimal design set by a balance of interpole diffusion and molar rate decay timescales.
To thread or not to thread? Effective potentials and threading interactions between asymmetric ring polymers
Using computer simulations of a system of two unlinked rings we show and explain how the threading roles of the rings can be exchanged when their length and bending stiffness are varied.
Machine learning enabled quantification of the hydrogen bonds inside the polyelectrolyte brush layer probed using all-atom molecular dynamics simulations
Machine learning method has been employed to quantify the changes in water–water hydrogen bonding inside densely grafted polyelectrolyte brush layer, as compared to the water–water hydrogen bonding outside the brush layer.
Effect of variations in manufacturing and material properties on the self-folding behaviors of hydrogel and elastomer bilayer structures
Thermal expansion model is adopted to predict the folding angles of the temperature-responsive nanocomposite hydrogel/elastomer bilayer structures to study the effect ofinevitable variations in manufacturing and material properties on folding angles.
High-χ, low-N micelles from partially perfluorinated block polymers
High-χ conditions from fluorophobic block polymers enable persistent micelles with core blocks consisting of just 11 mer units and having elongated conformations.
Interplay between substrate rigidity and tissue fluidity regulates cell monolayer spreading
Using a cell-based computational model of a spreading cell monolayer, we show that the interplay between tissue fluidity and substrate rigidity regulates the rate of collective spreading.
Yield precursor in primary creep of colloidal gels
Colloidal gels under moderate stress show an early precursor to yield detectable at macroscopic length scales. This precursor arises from accumulation of local plastic events.
Information-theoretical measures identify accurate low-resolution representations of protein configurational space
Different clustering strategies can produce qualitatively different low-resolution representations of a protein’s conformational space. The resolution-relevance framework pinpoints those that better preserve important, biologically relevant features.
Modulating membrane fusion through the design of fusogenic DNA circuits and bilayer composition
Control over lipid-membrane fusion is valuable in nanomedicine and synthetic biology. Here we provide guiding principles to program it by using fusogenic DNA nanostructures and exploring the effect of lipid composition on fusion efficiency.
Experimental investigation and finite element modelling of PMMA/carbon nanotube nanobiocomposites for bone cement applications
Multi-walled carbon nanotubes (MWCNTs) are one of the preferred candidates for reinforcing polymeric nanobiocomposites, such as acrylic bone types of cement.
Force-driven active dynamics of thin nanorods in unentangled polymer melts
Molecular simulation and scaling theory demonstrate the combination of an anisotropic “skinny” shape and a strong external force enables a nano-needle to pierce through a polymer matrix with reduced viscous resistance.
Self-assembly of carbon nanodots induced by liquid–liquid phase separation in a surface microdroplet
The film, porous and granular nanostructures are generated from evaporating carbon dot-laden ternary droplets. Liquid–liquid phase separation during evaporation is unravelled as a critical role in the controlled self-assembly of carbon nanodots.
Experimental determination of the bulk moduli of hollow nanogels
Small-angle neutron scattering with contrast variation is used to determine the bulk moduli of hollow nanogels. The cavity makes these nanogel extremely compressible at very low applied stress.
Self-assembly of globular proteins with intrinsically disordered protein polyelectrolytes and block copolymers
Intrinsically disordered polypeptides are a versatile class of materials, combining the biocompatibility of peptides with the disordered structure and diverse phase behaviors of synthetic polymers.
Quantitative analysis of biomolecule release from polystyrene-block-polyethylene oxide thin films
The concept of biomolecule release from co-assembled PS-b-PEO films (left) is depicted. The main findings (right) display an analysis of protein stability, a release comparison depending on cargo size, and tuning release by adjusting film thickness.
Controlling fine touch sensations with polymer tacticity and crystallinity
Humans can distinguish thin films of polystyrene which differed only in their degree of crystallinity.
A microfluidic platform for characterizing the structure and rheology of biofilm streamers
We present a microfluidic platform with isolated micropillars as nucleation sites for the reproducible formation of biofilm streamers, whose biochemical composition, morphology, and rheology can be systematically characterized in situ.
Subtle changes in pH affect the packing and robustness of fatty acid bilayers
Extremely small shifts in pH could have impacted the ability of fatty-acid-based primitive cells to thrive, with survival under osmotic stress and the ability to retain encapsulated material severely impacted at higher pHs.
Spontaneously rotating clusters of active droplets
We investigate the aggregation of hexagonally ordered clusters and the spontaneous emergence of their rotating and rising states in sedimenting suspensions of self-propelling isotropic oil droplets.
Dynamic effect of polymers at the surfactant–water interface: an ultrafast study
Interfaces play a role in controlling the rates and outcomes of chemical processes.
Rapid, interface-driven domain orientation in bottlebrush diblock copolymer films during thermal annealing
Thick (>20 μm) films of bottlebrush block copolymers self-assemble within minutes of thermal annealing between hard interfaces. Photonic properties are modified by thickness-dependent gradients of grain size and orientation between the surface and bulk.
In situ characterization of crystallization and melting of soft, thermoresponsive microgels by small-angle X-ray scattering
By combining thermoresponsive core–shell gold–PNIPAM microgels with USAXS, the crystallization and melting of soft colloidal crystals is investigated in detail with Bragg peak analysis.
From nematic shells to nematic droplets: energetics and defect transitions
We investigate the defect transitions that occur when a nematic shell is transformed into a droplet. Two different scenarios are observed depending on the initial defect structure of the shell, including an abrupt expulsion of the shell inner droplet.
Mechanical stress affects dynamics and rheology of the human genome
Using a novel noninvasive approach, we measure dynamics and rheology of the genome in live human cells before and after applying mechanical stress. We find that mechanical stress alters both dynamics and material properties of the genome.