ABSTRACT:Delamination is a key step to obtain individual layers from inorganic layered materials needed for fundamental studies and applications. For layered van-der-Waals materials like graphene the adhesion forces are small allowing for mechanical exfoliation, whereas for ionic layered materials like layered silicates the energy to separate adjacent layers is considerably higher. Quite counter intuitively, we show for a synthetic layered silicate (Na 0.5 -hectorite) that a scalable and quantitative delamination by simple hydration is possible for high and correlated. This is indicated by fulfilling the classical Hansen-Verlet and Lindeman criteria for melting. We provide insight into the requirements for layer separation and controlling the layer distances for a broad range of materials and outline an important pathway for the integration of layers into devices for advanced applications.

Block copolymer self-assembly in solution paves the way for the construction of well-defined compartmentalized nanostructures. These are excellent templates for the incorporation and stabilisation of nanoparticles (NPs), giving rise to highly relevant applications in the field of catalysis or sensing. However, the regio-selective incorporation of NPs in specific compartments is still an issue, especially concerning the loading with different NP types. Using crystallisation-driven self-assembly (CDSA), functional worm-like crystalline-core micelles (wCCMs) with a tailor-made, nanometre-sized patchy corona were prepared as versatile templates for the incorporation and stabilisation of metal and metal oxide NPs. Different strategies, like ligand exchange or co-precipitation of polymer stabilised NPs with one surface patch, were developed that allow the incorporation of NPs in specific regions of the patchy wCCM corona. Independent of the NP type and the incorporation method, the NPs showed no tendency for agglomeration and were fixed within the corona patches of the wCCMs. The binary loading of patchy micelles with metal and metal oxide NPs was realised by combining different loading strategies, yielding hybrids with homogeneously dispersed NPs guided by the patchy structure of the template.

In biological fluids, proteins bind to particles, forming so-called protein coronas. Such adsorbed protein layers significantly influence the biological interactions of particles, both in vitro and in vivo. The adsorbed protein layer is generally described as a two-component system comprising "hard" and "soft" protein coronas. However, a comprehensive picture regarding protein corona structure is lacking. Herein, we introduce an experimental approach that allows for in situ monitoring of protein adsorption onto silica microparticles. The technique, which mimics flow in vascularized tumors, combines confocal laser scanning microscopy with microfluidics and allows the study of the time-evolution of protein corona formation. Our results show that protein corona formation is kinetically divided into three different phases: phase 1, proteins irreversibly and directly bound (under physiologically relevant conditions) to the particle surface; phase 2, irreversibly bound proteins interacting with pre-adsorbed proteins, and phase 3, reversibly bound "soft" protein corona proteins. Additionally, we investigate particle-protein interactions on lowfouling zwitterionic-coated particles where the adsorption of irreversibly bound proteins does not occur, and on such particles only a "soft" protein corona is formed. The reported approach offers the potential to define new state-of-the art procedures for kinetics and protein fouling experiments. 9 Depending on the characterization method used, the protein corona is described according to either the Gibbs free energy ΔG, 8,10-12 which defines the adsorption and desorption rates of proteins, or binding force 13,14 between the proteins and particle surface. Proteins with a large ΔG have a low probability of desorption and therefore remain associated with the particle surface. These proteins are considered to form the "hard" protein corona. Distinction based on binding forces implies that "hard" protein corona proteins interact directly with the particle surface through long-range, strong protein-surface interactions, whereas proteins in the "soft" protein corona interact with other proteins through short-range, weak protein-protein interactions. Another theoretical distinction is based on the persistence of the protein to remain adsorbed throughout the nanoparticle's journey (i.e. from bloodstream to tissue and past-endocytic environments) as protein corona composition changes during biophysical events. 6-8,15,16 The concept of "persistent" proteins 5 originates from studies where the "hard" protein corona is used to follow the particle's past. 17-19 It is becoming increasingly important to clearly understand the complex process of protein corona formation, with a focus on the influence of the "soft" protein corona on physiological interactions. 4,7,13,20-24 However, to do so, it is crucial to acquire and understand further details such as the time-evolution of protein corona formation. Existing techniques for investigating the protein corona can be divided into ex situ and in situ ...

We report the fabrication of highly permeable membranes in poly(ethylene glycol) diacrylate (PEGDA) channels, for investigating ultra- or micro-filtration, at the microfluidic scale. More precisely, we used a maskless UV projection setup to photo-pattern PEG-based hydrogel membranes on a large scale (mm-cm), and with a spatial resolution of a few microns. We show that these membranes can withstand trans-membrane pressure drops of up to 7 bar without any leakage, thanks to the strong anchoring of the hydrogel to the channel walls. We also report in situ measurements of the Darcy permeability of these membranes, as a function of the deposited energy during photo-polymerization, and their formulation composition. We show that the use of PEG chains as porogens, as proposed in [Lee et al., Biomacromolecules, 2010, 11, 3316], significantly increases the porosity of the hydrogels, up to Darcy permeabilities of about 1.5 × 10-16 m2, while maintaining the strong mechanical stability of the membranes. We finally illustrate the opportunities offered by this technique, by investigating frontal filtration of colloidal dispersions in a straight microfluidic channel.

Liquid microjets play a key role in fiber spinning, inkjet printing, and coating processes. In all of these applications, the liquid jets carry dispersed particles whose spatial and orientational distributions within the jet critically influence the properties of the fabricated structures. Despite its importance, there is currently no knowledge about the orientational distribution of particles within microjets and droplets. Here, we demonstrate a microfluidic device that allows to determine the local particle distribution and orientation by X-ray scattering. Using this methodology, we discovered unexpected changes in the particle orientation upon exiting the nozzle to form a free jet, and upon jet break-up into droplets, causing an unusual biaxial particle orientation. We show how flow and aspect ratio determine the flow orientation of anisotropic particles. Furthermore, we demonstrate that the observed phenomena are a general characteristic of anisotropic particles. Our findings greatly enhance our understanding of particle orientation in free jets and droplets and provide a rationale for controlling particle alignment in liquid jet-based fabrication methodologies.