TY - JOUR AB - The epitaxial growth of a strained Ge layer, which is a promising candidate for the channel material of a hole spin qubit, has been demonstrated on 300 mm Si wafers using commercially available Si0.3Ge0.7 strain relaxed buffer (SRB) layers. The assessment of the layer and the interface qualities for a buried strained Ge layer embedded in Si0.3Ge0.7 layers is reported. The XRD reciprocal space mapping confirmed that the reduction of the growth temperature enables the 2-dimensional growth of the Ge layer fully strained with respect to the Si0.3Ge0.7. Nevertheless, dislocations at the top and/or bottom interface of the Ge layer were observed by means of electron channeling contrast imaging, suggesting the importance of the careful dislocation assessment. The interface abruptness does not depend on the selection of the precursor gases, but it is strongly influenced by the growth temperature which affects the coverage of the surface H-passivation. The mobility of 2.7 × 105 cm2/Vs is promising, while the low percolation density of 3 × 1010 /cm2 measured with a Hall-bar device at 7 K illustrates the high quality of the heterostructure thanks to the high Si0.3Ge0.7 SRB quality. AU - Shimura, Yosuke AU - Godfrin, Clement AU - Hikavyy, Andriy AU - Li, Roy AU - Aguilera Servin, Juan L AU - Katsaros, Georgios AU - Favia, Paola AU - Han, Han AU - Wan, Danny AU - de Greve, Kristiaan AU - Loo, Roger ID - 15018 IS - 5 JF - Materials Science in Semiconductor Processing KW - Mechanical Engineering KW - Mechanics of Materials KW - Condensed Matter Physics KW - General Materials Science SN - 1369-8001 TI - Compressively strained epitaxial Ge layers for quantum computing applications VL - 174 ER - TY - JOUR AB - High entropy alloys (HEAs) are highly suitable candidate catalysts for oxygen evolution and reduction reactions (OER/ORR) as they offer numerous parameters for optimizing the electronic structure and catalytic sites. Herein, FeCoNiMoW HEA nanoparticles are synthesized using a solution‐based low‐temperature approach. Such FeCoNiMoW nanoparticles show high entropy properties, subtle lattice distortions, and modulated electronic structure, leading to superior OER performance with an overpotential of 233 mV at 10 mA cm−2 and 276 mV at 100 mA cm−2. Density functional theory calculations reveal the electronic structures of the FeCoNiMoW active sites with an optimized d‐band center position that enables suitable adsorption of OOH* intermediates and reduces the Gibbs free energy barrier in the OER process. Aqueous zinc–air batteries (ZABs) based on this HEA demonstrate a high open circuit potential of 1.59 V, a peak power density of 116.9 mW cm−2, a specific capacity of 857 mAh gZn−1, and excellent stability for over 660 h of continuous charge–discharge cycles. Flexible and solid ZABs are also assembled and tested, displaying excellent charge–discharge performance at different bending angles. This work shows the significance of 4d/5d metal‐modulated electronic structure and optimized adsorption ability to improve the performance of OER/ORR, ZABs, and beyond. AU - He, Ren AU - Yang, Linlin AU - Zhang, Yu AU - Jiang, Daochuan AU - Lee, Seungho AU - Horta, Sharona AU - Liang, Zhifu AU - Lu, Xuan AU - Ostovari Moghaddam, Ahmad AU - Li, Junshan AU - Ibáñez, Maria AU - Xu, Ying AU - Zhou, Yingtang AU - Cabot, Andreu ID - 14434 JF - Advanced Materials KW - Mechanical Engineering KW - Mechanics of Materials KW - General Materials Science SN - 0935-9648 TI - A 3d‐4d‐5d high entropy alloy as a bifunctional oxygen catalyst for robust aqueous zinc–air batteries ER - TY - JOUR AB - Low‐cost, safe, and environmental‐friendly rechargeable aqueous zinc‐ion batteries (ZIBs) are promising as next‐generation energy storage devices for wearable electronics among other applications. However, sluggish ionic transport kinetics and the unstable electrode structure during ionic insertion/extraction hampers their deployment. Herein,  we propose a new cathode material based on a layered metal chalcogenide (LMC), bismuth telluride (Bi2Te3), coated with polypyrrole (PPy). Taking advantage of the PPy coating, the Bi2Te3@PPy composite presents strong ionic absorption affinity, high oxidation resistance, and high structural stability. The ZIBs based on Bi2Te3@PPy cathodes exhibit high capacities and ultra‐long lifespans of over 5000 cycles. They also present outstanding stability even under bending. In addition,  we analyze here the reaction mechanism using in situ X‐ray diffraction, X‐ray photoelectron spectroscopy, and computational tools and demonstrate that, in the aqueous system, Zn2+ is not inserted into the cathode as previously assumed. In contrast, proton charge storage dominates the process. Overall, this work not only shows the great potential of LMCs as ZIBs cathode materials and the advantages of PPy coating, but also clarifies the charge/discharge mechanism in rechargeable ZIBs based on LMCs. AU - Zeng, Guifang AU - Sun, Qing AU - Horta, Sharona AU - Wang, Shang AU - Lu, Xuan AU - Zhang, Chaoyue AU - Li, Jing AU - Li, Junshan AU - Ci, Lijie AU - Tian, Yanhong AU - Ibáñez, Maria AU - Cabot, Andreu ID - 14435 JF - Advanced Materials KW - Mechanical Engineering KW - Mechanics of Materials KW - General Materials Science SN - 0935-9648 TI - A layered Bi2Te3@PPy cathode for aqueous zinc ion batteries: Mechanism and application in printed flexible batteries ER - TY - JOUR AB - Multistable systems are characterized by exhibiting domain coexistence, where each domain accounts for the different equilibrium states. In case these systems are described by vectorial fields, domains can be connected through topological defects. Vortices are one of the most frequent and studied topological defect points. Optical vortices are equally relevant for their fundamental features as beams with topological features and their applications in image processing, telecommunications, optical tweezers, and quantum information. A natural source of optical vortices is the interaction of light beams with matter vortices in liquid crystal cells. The rhythms that govern the emergence of matter vortices due to fluctuations are not established. Here, we investigate the nucleation mechanisms of the matter vortices in liquid crystal cells and establish statistical laws that govern them. Based on a stochastic amplitude equation, the law for the number of nucleated vortices as a function of anisotropy, voltage, and noise level intensity is set. Experimental observations in a nematic liquid crystal cell with homeotropic anchoring and a negative anisotropic dielectric constant under the influence of a transversal electric field show a qualitative agreement with the theoretical findings. AU - Aguilera, Esteban AU - Clerc, Marcel G. AU - Zambra, Valeska ID - 11343 JF - Nonlinear Dynamics KW - Electrical and Electronic Engineering KW - Applied Mathematics KW - Mechanical Engineering KW - Ocean Engineering KW - Aerospace Engineering KW - Control and Systems Engineering SN - 0924-090X TI - Vortices nucleation by inherent fluctuations in nematic liquid crystal cells VL - 108 ER - TY - JOUR AB - We investigate the local self-sustained process underlying spiral turbulence in counter-rotating Taylor–Couette flow using a periodic annular domain, shaped as a parallelogram, two of whose sides are aligned with the cylindrical helix described by the spiral pattern. The primary focus of the study is placed on the emergence of drifting–rotating waves (DRW) that capture, in a relatively small domain, the main features of coherent structures typically observed in developed turbulence. The transitional dynamics of the subcritical region, far below the first instability of the laminar circular Couette flow, is determined by the upper and lower branches of DRW solutions originated at saddle-node bifurcations. The mechanism whereby these solutions self-sustain, and the chaotic dynamics they induce, are conspicuously reminiscent of other subcritical shear flows. Remarkably, the flow properties of DRW persist even as the Reynolds number is increased beyond the linear stability threshold of the base flow. Simulations in a narrow parallelogram domain stretched in the azimuthal direction to revolve around the apparatus a full turn confirm that self-sustained vortices eventually concentrate into a localised pattern. The resulting statistical steady state satisfactorily reproduces qualitatively, and to a certain degree also quantitatively, the topology and properties of spiral turbulence as calculated in a large periodic domain of sufficient aspect ratio that is representative of the real system. AU - Wang, B. AU - Ayats López, Roger AU - Deguchi, K. AU - Mellibovsky, F. AU - Meseguer, A. ID - 12137 JF - Journal of Fluid Mechanics KW - Mechanical Engineering KW - Mechanics of Materials KW - Condensed Matter Physics KW - Applied Mathematics SN - 0022-1120 TI - Self-sustainment of coherent structures in counter-rotating Taylor–Couette flow VL - 951 ER - TY - JOUR AB - In the class of strictly convex smooth boundaries each of which has no strip around its boundary foliated by invariant curves, we prove that the Taylor coefficients of the “normalized” Mather’s β-function are invariant under C∞-conjugacies. In contrast, we prove that any two elliptic billiard maps are C0-conjugate near their respective boundaries, and C∞-conjugate, near the boundary and away from a line passing through the center of the underlying ellipse. We also prove that, if the billiard maps corresponding to two ellipses are topologically conjugate, then the two ellipses are similar. AU - Koudjinan, Edmond AU - Kaloshin, Vadim ID - 12145 IS - 6 JF - Regular and Chaotic Dynamics KW - Mechanical Engineering KW - Applied Mathematics KW - Mathematical Physics KW - Modeling and Simulation KW - Statistical and Nonlinear Physics KW - Mathematics (miscellaneous) SN - 1560-3547 TI - On some invariants of Birkhoff billiards under conjugacy VL - 27 ER - TY - JOUR AB - Supramolecular self-assembly in biological systems holds promise to convert and amplify disease-specific signals to physical or mechanical signals that can direct cell fate. However, it remains challenging to design physiologically stable self-assembling systems that demonstrate tunable and predictable behavior. Here, the use of zwitterionic tetrapeptide modalities to direct nanoparticle assembly under physiological conditions is reported. The self-assembly of gold nanoparticles can be activated by enzymatic unveiling of surface-bound zwitterionic tetrapeptides through matrix metalloprotease-9 (MMP-9), which is overexpressed by cancer cells. This robust nanoparticle assembly is achieved by multivalent, self-complementary interactions of the zwitterionic tetrapeptides. In cancer cells that overexpress MMP-9, the nanoparticle assembly process occurs near the cell membrane and causes size-induced selection of cellular uptake mechanism, resulting in diminished cell growth. The enzyme responsiveness, and therefore, indirectly, the uptake route of the system can be programmed by customizing the peptide sequence: a simple inversion of the two amino acids at the cleavage site completely inactivates the enzyme responsiveness, self-assembly, and consequently changes the endocytic pathway. This robust self-complementary, zwitterionic peptide design demonstrates the use of enzyme-activated electrostatic side-chain patterns as powerful and customizable peptide modalities to program nanoparticle self-assembly and alter cellular response in biological context. AU - Huang, Richard H. AU - Nayeem, Nazia AU - He, Ye AU - Morales, Jorge AU - Graham, Duncan AU - Klajn, Rafal AU - Contel, Maria AU - O'Brien, Stephen AU - Ulijn, Rein V. ID - 13355 IS - 1 JF - Advanced Materials KW - Mechanical Engineering KW - Mechanics of Materials KW - General Materials Science SN - 0935-9648 TI - Self‐complementary zwitterionic peptides direct nanoparticle assembly and enable enzymatic selection of endocytic pathways VL - 34 ER - TY - JOUR AB - In this paper, we explore the stability and dynamical relevance of a wide variety of steady, time-periodic, quasiperiodic, and chaotic flows arising between orthogonally stretching parallel plates. We first explore the stability of all the steady flow solution families formerly identified by Ayats et al. [“Flows between orthogonally stretching parallel plates,” Phys. Fluids 33, 024103 (2021)], concluding that only the one that originates from the Stokesian approximation is actually stable. When both plates are shrinking at identical or nearly the same deceleration rates, this Stokesian flow exhibits a Hopf bifurcation that leads to stable time-periodic regimes. The resulting time-periodic orbits or flows are tracked for different Reynolds numbers and stretching rates while monitoring their Floquet exponents to identify secondary instabilities. It is found that these time-periodic flows also exhibit Neimark–Sacker bifurcations, generating stable quasiperiodic flows (tori) that may sometimes give rise to chaotic dynamics through a Ruelle–Takens–Newhouse scenario. However, chaotic dynamics is unusually observed, as the quasiperiodic flows generally become phase-locked through a resonance mechanism before a strange attractor may arise, thus restoring the time-periodicity of the flow. In this work, we have identified and tracked four different resonance regions, also known as Arnold tongues or horns. In particular, the 1 : 4 strong resonance region is explored in great detail, where the identified scenarios are in very good agreement with normal form theory. AU - Wang, B. AU - Ayats López, Roger AU - Meseguer, A. AU - Marques, F. ID - 12146 IS - 11 JF - Physics of Fluids KW - Condensed Matter Physics KW - Fluid Flow and Transfer Processes KW - Mechanics of Materials KW - Computational Mechanics KW - Mechanical Engineering SN - 1070-6631 TI - Phase-locking flows between orthogonally stretching parallel plates VL - 34 ER - TY - JOUR AB - Several Ising-type magnetic van der Waals (vdW) materials exhibit stable magnetic ground states. Despite these clear experimental demonstrations, a complete theoretical and microscopic understanding of their magnetic anisotropy is still lacking. In particular, the validity limit of identifying their one-dimensional (1-D) Ising nature has remained uninvestigated in a quantitative way. Here we performed the complete mapping of magnetic anisotropy for a prototypical Ising vdW magnet FePS3 for the first time. Combining torque magnetometry measurements with their magnetostatic model analysis and the relativistic density functional total energy calculations, we successfully constructed the three-dimensional (3-D) mappings of the magnetic anisotropy in terms of magnetic torque and energy. The results not only quantitatively confirm that the easy axis is perpendicular to the ab plane, but also reveal the anisotropies within the ab, ac, and bc planes. Our approach can be applied to the detailed quantitative study of magnetism in vdW materials. AU - Nauman, Muhammad AU - Kiem, Do Hoon AU - Lee, Sungmin AU - Son, Suhan AU - Park, J-G AU - Kang, Woun AU - Han, Myung Joon AU - Jo, Youn Jung ID - 9282 IS - 3 JF - 2D Materials KW - Mechanical Engineering KW - General Materials Science KW - Mechanics of Materials KW - General Chemistry KW - Condensed Matter Physics SN - 2053-1583 TI - Complete mapping of magnetic anisotropy for prototype Ising van der Waals FePS3 VL - 8 ER - TY - JOUR AB - Solution synthesis of particles emerged as an alternative to prepare thermoelectric materials with less demanding processing conditions than conventional solid-state synthetic methods. However, solution synthesis generally involves the presence of additional molecules or ions belonging to the precursors or added to enable solubility and/or regulate nucleation and growth. These molecules or ions can end up in the particles as surface adsorbates and interfere in the material properties. This work demonstrates that ionic adsorbates, in particular Na⁺ ions, are electrostatically adsorbed in SnSe particles synthesized in water and play a crucial role not only in directing the material nano/microstructure but also in determining the transport properties of the consolidated material. In dense pellets prepared by sintering SnSe particles, Na remains within the crystal lattice as dopant, in dislocations, precipitates, and forming grain boundary complexions. These results highlight the importance of considering all the possible unintentional impurities to establish proper structure-property relationships and control material properties in solution-processed thermoelectric materials. AU - Liu, Yu AU - Calcabrini, Mariano AU - Yu, Yuan AU - Genç, Aziz AU - Chang, Cheng AU - Costanzo, Tommaso AU - Kleinhanns, Tobias AU - Lee, Seungho AU - Llorca, Jordi AU - Cojocaru‐Mirédin, Oana AU - Ibáñez, Maria ID - 10123 IS - 52 JF - Advanced Materials KW - mechanical engineering KW - mechanics of materials KW - general materials science SN - 0935-9648 TI - The importance of surface adsorbates in solution‐processed thermoelectric materials: The case of SnSe VL - 33 ER - TY - JOUR AB - We derive optimal-order homogenization rates for random nonlinear elliptic PDEs with monotone nonlinearity in the uniformly elliptic case. More precisely, for a random monotone operator on \mathbb {R}^d with stationary law (that is spatially homogeneous statistics) and fast decay of correlations on scales larger than the microscale \varepsilon >0, we establish homogenization error estimates of the order \varepsilon in case d\geqq 3, and of the order \varepsilon |\log \varepsilon |^{1/2} in case d=2. Previous results in nonlinear stochastic homogenization have been limited to a small algebraic rate of convergence \varepsilon ^\delta . We also establish error estimates for the approximation of the homogenized operator by the method of representative volumes of the order (L/\varepsilon )^{-d/2} for a representative volume of size L. Our results also hold in the case of systems for which a (small-scale) C^{1,\alpha } regularity theory is available. AU - Fischer, Julian L AU - Neukamm, Stefan ID - 10549 IS - 1 JF - Archive for Rational Mechanics and Analysis KW - Mechanical Engineering KW - Mathematics (miscellaneous) KW - Analysis SN - 0003-9527 TI - Optimal homogenization rates in stochastic homogenization of nonlinear uniformly elliptic equations and systems VL - 242 ER - TY - JOUR AB - We report the observation of an anomalous nonlinear optical response of the prototypical three-dimensional topological insulator bismuth selenide through the process of high-order harmonic generation. We find that the generation efficiency increases as the laser polarization is changed from linear to elliptical, and it becomes maximum for circular polarization. With the aid of a microscopic theory and a detailed analysis of the measured spectra, we reveal that such anomalous enhancement encodes the characteristic topology of the band structure that originates from the interplay of strong spin–orbit coupling and time-reversal symmetry protection. The implications are in ultrafast probing of topological phase transitions, light-field driven dissipationless electronics, and quantum computation. AU - Baykusheva, Denitsa Rangelova AU - Chacón, Alexis AU - Lu, Jian AU - Bailey, Trevor P. AU - Sobota, Jonathan A. AU - Soifer, Hadas AU - Kirchmann, Patrick S. AU - Rotundu, Costel AU - Uher, Ctirad AU - Heinz, Tony F. AU - Reis, David A. AU - Ghimire, Shambhu ID - 13996 IS - 21 JF - Nano Letters KW - Mechanical Engineering KW - Condensed Matter Physics KW - General Materials Science KW - General Chemistry KW - Bioengineering SN - 1530-6984 TI - All-optical probe of three-dimensional topological insulators based on high-harmonic generation by circularly polarized laser fields VL - 21 ER - TY - JOUR AB - Recent discoveries have shown that, when two layers of van der Waals (vdW) materials are superimposed with a relative twist angle between them, the electronic properties of the coupled system can be dramatically altered. Here, we demonstrate that a similar concept can be extended to the optics realm, particularly to propagating phonon polaritons–hybrid light-matter interactions. To do this, we fabricate stacks composed of two twisted slabs of a vdW crystal (α-MoO3) supporting anisotropic phonon polaritons (PhPs), and image the propagation of the latter when launched by localized sources. Our images reveal that, under a critical angle, the PhPs isofrequency curve undergoes a topological transition, in which the propagation of PhPs is strongly guided (canalization regime) along predetermined directions without geometric spreading. These results demonstrate a new degree of freedom (twist angle) for controlling the propagation of polaritons at the nanoscale with potential for nanoimaging, (bio)-sensing, or heat management. AU - Duan, Jiahua AU - Capote-Robayna, Nathaniel AU - Taboada-Gutiérrez, Javier AU - Álvarez-Pérez, Gonzalo AU - Prieto Gonzalez, Ivan AU - Martín-Sánchez, Javier AU - Nikitin, Alexey Y. AU - Alonso-González, Pablo ID - 10866 IS - 7 JF - Nano Letters KW - Mechanical Engineering KW - Condensed Matter Physics KW - General Materials Science KW - General Chemistry KW - Bioengineering SN - 1530-6984 TI - Twisted nano-optics: Manipulating light at the nanoscale with twisted phonon polaritonic slabs VL - 20 ER - TY - THES AB - Fabrication of curved shells plays an important role in modern design, industry, and science. Among their remarkable properties are, for example, aesthetics of organic shapes, ability to evenly distribute loads, or efficient flow separation. They find applications across vast length scales ranging from sky-scraper architecture to microscopic devices. But, at the same time, the design of curved shells and their manufacturing process pose a variety of challenges. In this thesis, they are addressed from several perspectives. In particular, this thesis presents approaches based on the transformation of initially flat sheets into the target curved surfaces. This involves problems of interactive design of shells with nontrivial mechanical constraints, inverse design of complex structural materials, and data-driven modeling of delicate and time-dependent physical properties. At the same time, two newly-developed self-morphing mechanisms targeting flat-to-curved transformation are presented. In architecture, doubly curved surfaces can be realized as cold bent glass panelizations. Originally flat glass panels are bent into frames and remain stressed. This is a cost-efficient fabrication approach compared to hot bending, when glass panels are shaped plastically. However such constructions are prone to breaking during bending, and it is highly nontrivial to navigate the design space, keeping the panels fabricable and aesthetically pleasing at the same time. We introduce an interactive design system for cold bent glass façades, while previously even offline optimization for such scenarios has not been sufficiently developed. Our method is based on a deep learning approach providing quick and high precision estimation of glass panel shape and stress while handling the shape multimodality. Fabrication of smaller objects of scales below 1 m, can also greatly benefit from shaping originally flat sheets. In this respect, we designed new self-morphing shell mechanisms transforming from an initial flat state to a doubly curved state with high precision and detail. Our so-called CurveUps demonstrate the encodement of the geometric information into the shell. Furthermore, we explored the frontiers of programmable materials and showed how temporal information can additionally be encoded into a flat shell. This allows prescribing deformation sequences for doubly curved surfaces and, thus, facilitates self-collision avoidance enabling complex shapes and functionalities otherwise impossible. Both of these methods include inverse design tools keeping the user in the design loop. AU - Guseinov, Ruslan ID - 8366 KW - computer-aided design KW - shape modeling KW - self-morphing KW - mechanical engineering SN - 2663-337X TI - Computational design of curved thin shells: From glass façades to programmable matter ER - TY - JOUR AB - Advances in shape-morphing materials, such as hydrogels, shape-memory polymers and light-responsive polymers have enabled prescribing self-directed deformations of initially flat geometries. However, most proposed solutions evolve towards a target geometry without considering time-dependent actuation paths. To achieve more complex geometries and avoid self-collisions, it is critical to encode a spatial and temporal shape evolution within the initially flat shell. Recent realizations of time-dependent morphing are limited to the actuation of few, discrete hinges and cannot form doubly curved surfaces. Here, we demonstrate a method for encoding temporal shape evolution in architected shells that assume complex shapes and doubly curved geometries. The shells are non-periodic tessellations of pre-stressed contractile unit cells that soften in water at rates prescribed locally by mesostructure geometry. The ensuing midplane contraction is coupled to the formation of encoded curvatures. We propose an inverse design tool based on a data-driven model for unit cells’ temporal responses. AU - Guseinov, Ruslan AU - McMahan, Connor AU - Perez Rodriguez, Jesus AU - Daraio, Chiara AU - Bickel, Bernd ID - 7262 JF - Nature Communications KW - Design KW - Synthesis and processing KW - Mechanical engineering KW - Polymers SN - 2041-1723 TI - Programming temporal morphing of self-actuated shells VL - 11 ER - TY - JOUR AB - We demonstrate a method for manipulating small ensembles of vortices in multiply connected superconducting structures. A micron-size magnetic particle attached to the tip of a silicon cantilever is used to locally apply magnetic flux through the superconducting structure. By scanning the tip over the surface of the device and by utilizing the dynamical coupling between the vortices and the cantilever, a high-resolution spatial map of the different vortex configurations is obtained. Moving the tip to a particular location in the map stabilizes a distinct multivortex configuration. Thus, the scanning of the tip over a particular trajectory in space permits nontrivial operations to be performed, such as braiding of individual vortices within a larger vortex ensemble—a key capability required by many proposals for topological quantum computing. AU - Polshyn, Hryhoriy AU - Naibert, Tyler AU - Budakian, Raffi ID - 10622 IS - 8 JF - Nano Letters KW - mechanical engineering KW - condensed matter physics KW - general materials science KW - general chemistry KW - bioengineering SN - 1530-6984 TI - Manipulating multivortex states in superconducting structures VL - 19 ER - TY - JOUR AB - For the Restricted Circular Planar 3 Body Problem, we show that there exists an open set U in phase space of fixed measure, where the set of initial points which lead to collision is O(μ120) dense as μ→0. AU - Guardia, Marcel AU - Kaloshin, Vadim AU - Zhang, Jianlu ID - 8418 IS - 2 JF - Archive for Rational Mechanics and Analysis KW - Mechanical Engineering KW - Mathematics (miscellaneous) KW - Analysis SN - 0003-9527 TI - Asymptotic density of collision orbits in the Restricted Circular Planar 3 Body Problem VL - 233 ER - TY - JOUR AB - The ability to reversibly assemble nanoparticles using light is both fundamentally interesting and important for applications ranging from reversible data storage to controlled drug delivery. Here, the diverse approaches that have so far been developed to control the self-assembly of nanoparticles using light are reviewed and compared. These approaches include functionalizing nanoparticles with monolayers of photoresponsive molecules, placing them in photoresponsive media capable of reversibly protonating the particles under light, and decorating plasmonic nanoparticles with thermoresponsive polymers, to name just a few. The applicability of these methods to larger, micrometer-sized particles is also discussed. Finally, several perspectives on further developments in the field are offered. AU - Bian, Tong AU - Chu, Zonglin AU - Klajn, Rafal ID - 13366 IS - 20 JF - Advanced Materials KW - Mechanical Engineering KW - Mechanics of Materials KW - General Materials Science SN - 0935-9648 TI - The many ways to assemble nanoparticles using light VL - 32 ER - TY - JOUR AB - Efficient isomerization of photochromic molecules often requires conformational freedom and is typically not available under solvent-free conditions. Here, we report a general methodology allowing for reversible switching of such molecules on the surfaces of solid materials. Our method is based on dispersing photochromic compounds within polysilsesquioxane nanowire networks (PNNs), which can be fabricated as transparent, highly porous, micrometer-thick layers on various substrates. We found that azobenzene switching within the PNNs proceeded unusually fast compared with the same molecules in liquid solvents. Efficient isomerization of another photochromic system, spiropyran, from a colorless to a colored form was used to create reversible images in PNN-coated glass. The coloration reaction could be induced with sunlight and is of interest for developing “smart” windows. AU - Chu, Zonglin AU - Klajn, Rafal ID - 13370 IS - 10 JF - Nano Letters KW - Mechanical Engineering KW - Condensed Matter Physics KW - General Materials Science KW - General Chemistry KW - Bioengineering SN - 1530-6984 TI - Polysilsesquioxane nanowire networks as an “Artificial Solvent” for reversible operation of photochromic molecules VL - 19 ER - TY - JOUR AB - Biological membranes typically contain a large number of different components dispersed in small concentrations in the main membrane phase, including proteins, sugars, and lipids of varying geometrical properties. Most of these components do not bind the cargo. Here, we show that such “inert” components can be crucial for the precise control of cross-membrane trafficking. Using a statistical mechanics model and molecular dynamics simulations, we demonstrate that the presence of inert membrane components of small isotropic curvatures dramatically influences cargo endocytosis, even if the total spontaneous curvature of such a membrane remains unchanged. Curved lipids, such as cholesterol, as well as asymmetrically included proteins and tethered sugars can, therefore, actively participate in the control of the membrane trafficking of nanoscopic cargo. We find that even a low-level expression of curved inert membrane components can determine the membrane selectivity toward the cargo size and can be used to selectively target membranes of certain compositions. Our results suggest a robust and general method of controlling cargo trafficking by adjusting the membrane composition without needing to alter the concentration of receptors or the average membrane curvature. This study indicates that cells can prepare for any trafficking event by incorporating curved inert components in either of the membrane leaflets. AU - Curk, Tine AU - Wirnsberger, Peter AU - Dobnikar, Jure AU - Frenkel, Daan AU - Šarić, Anđela ID - 10359 IS - 9 JF - Nano Letters KW - mechanical engineering KW - condensed matter physics SN - 1530-6984 TI - Controlling cargo trafficking in multicomponent membranes VL - 18 ER -