Folding robots and metamaterials The same principles used to make origami art can self-assembling tunable metamaterials—artificial materials engineered have properties that may not be found in nature (see the Perspective by You). Felton et al. made complex self-folding from flat templates. Such could potentially sent through a collapsed building or tunnels then assemble themselves autonomously into their final functional form. Silverberg created mechanical metamaterial was folded tessellated...

Self-actuating materials capable of transforming between three-dimensional shapes have applications in areas as diverse biomedicine, robotics, and tunable micro-optics. We introduce a method photopatterning polymer films that yields temperature-responsive gel sheets can transform flat state prescribed shape. Our approach is based on poly(N-isopropylacrylamide) copolymers containing pendent benzophenone units allow cross-linking to be tuned by irradiation dose. describe simple halftone...

Well-ordered mesostructured silica and titania films were prepared using poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) triblock copolymer species (Pluronic P123) as the structure-directing agents. By varying volume ratio between inorganic components of precursor solution, thin with cubic, 2D hexagonal, lamellar mesostructures prepared. The regions over which three phases obtained correspond well those water−block binary phase diagram when considered in terms fraction...

Block copolymers have the capacity to self-organize into a myriad of aggregate structures when placed in selective solvents, offering great promise for construction delivery vehicles and complex nanoscale assemblies. A key feature these materials is their propensity become kinetically trapped nonequilibrium states, meaning that they adopt depend sensitively on processing route taken. While this makes it challenging fully explore landscape possible morphologies, also means careful attention...

A novel and highly scalable approach to generating a reusable, "smart" polymer adhesive based on surface wrinkling is presented. The patterning the film combination of swelling lateral confinement. control adhesion, or adhesion utilizes mechanism contact line splitting. This enhancement controlled by wrinkle wavelength, which tuned degree

Self-folding microscale origami patterns are demonstrated in polymer films with control over mountain/valley assignments and fold angles using trilayers of photo-crosslinkable copolymers a temperature-sensitive hydrogel as the middle layer. The characteristic size scale folds W = 30 μm figure merit A/ (2) ≈ 5000, here represent substantial advances fabrication self-folding origami.

ConspectusThe formation of well-defined and functional three-dimensional (3D) structures by buckling thin sheets subjected to spatially nonuniform stresses is common in biological morphogenesis has become a subject great interest synthetic systems, as such programmable shape-morphing materials hold promise areas including drug delivery, biomedical devices, soft robotics, biomimetic systems. Given their ability undergo large changes swelling response wide variety stimuli, hydrogels have...

We have investigated the rheological properties of lyotropic liquid crystals (LCs) formed by self-assembled neutral lipids and water, their relationship with topology structure, dependence on temperature water content. The phase diagram a representative monoglyceride-water system, determined combining cross-polarized optical microscopy small-angle X-ray scattering (SAXS), included four structures: lamellar, hexagonal, gyroid bicontinuous cubic (Ia3d), double diamond (Pn3m), as well several...

Ionic elastomeric material electronics Wearable devices often need to be soft or flexible, and ideally, these properties would extend beyond packaging also include the electronics. Some ionic conductors have been made in form of stretchable, transparent devices, but leaks from materials is a concern. Kim et al. demonstrate diodes transistors that harness double layers rectify switch currents (see Perspective by Gao Lee). This achieved without trapped liquids fixing anions cations an...

Abstract Liquid crystal elastomers (LCEs) are an attractive platform for dynamic shape‐morphing due to their ability rapidly undergo large deformations. While recent work has focused on patterning the director orientation field achieve desired target shapes, this strategy cannot be generalized material systems where high‐resolution surface alignment is impractical. Instead of programming local anisotropic deformation, alternative prescribed by magnitude stretch ratio in a thin LCE sheet with...

Two-photon polymerization (TPP) currently offers the highest resolution available in 3D printing (∼100 nm) but requires femtosecond laser pulses at very high peak intensity (∼1 TW/cm2). Here, we demonstrate based on triplet-triplet-annihilation photopolymerization (TTAP), which achieves submicron while using a continuous visible LED light source with comparatively low (∼10 W/cm2). TTAP enables submicrometer feature sizes exposure times of ∼0.1 s/voxel without requiring coherent or pulsed...

The unidirectional expansion of a thin surface-attached polymer gel upon swelling by solvent generates biaxial compressive stress within the gel. For sufficiently large stresses, mechanical instability can occur in which free surface locally buckles and folds against itself to form creases. This has important implications for design biomaterials, smart surfaces, sensors, since it places fundamental limit on amount that layer may undergo without forming topographical features. However, while...

Thin poly(N-isopropylacrylamide) (PNIPAM) hydrogels were allowed to swell under two conditions: as freestanding layers and substrate-attached layers. Through a combination of particle tracking defocusing methods, the positions beads embedded within gels monitored over time via fluorescence microscopy, providing convenient method track kinetics swelling for with thicknesses order 100 µm. These data are compared predictions linear poroelastic theory, specialized polymer gels. This along single...

We introduce a method for the formation of block copolymer micelles through interfacial instabilities emulsion droplets. Amphiphilic polystyrene-block-poly(ethylene oxide) (PS-PEO) copolymers are first dissolved in chloroform; this solution is then emulsified water and chloroform extracted by evaporation. As droplets shrink, organic solvent/water interface becomes unstable, spontaneously generating new leading to dispersion as micellar aggregates aqueous phase. Depending on composition...

We report on the solution-state assembly of all-conjugated polythiophene diblock copolymers containing nonpolar (hexyl) and polar (triethylene glycol) side chains. The substituents provide a large contrast in solubility, enabling formation stably suspended crystalline fibrils even under very poor solvent conditions for poly(3-hexylthiophene) block. For appropriate block ratios, complexation triethylene glycol chains with added potassium ions drives helical nanowires that further bundle into...

The process by which spatial variations in growth transform two-dimensional elastic membranes into three-dimensional shapes is both a fundamentally interesting mechanism of shape selection and powerful tool for the preparation responsive materials. From perspective lithographic patterning thin gel sheets, it most straightforward to prepare materials consisting discrete regions with different degrees swelling. However, sharp swelling at boundaries between such make impossible sheet adopt...

We investigate the formation of polymer vesicles, or polymersomes, polystyrene-block-poly(ethylene oxide) diblock copolymers using double emulsion droplets controlled architecture as templates. To engineer structure it is important to consider concentration copolymer in middle phase emulsion. describe how presence excess can induce a transition from complete wetting partial phase, resulting shells with inhomogeneous thicknesses.

Patterning deformation within the plane of thin elastic sheets represents a powerful tool for definition complex and stimuli-responsive 3D buckled shapes. Previous experimental methods, however, have focused on that access limited number shapes pre-programmed into sheet, restricting degree dynamic control. Here, we demonstrate on-demand reconfigurable buckling poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAM) hydrogel network films containing gold nanoparticles (AuNPs) by patterned...

Nanoparticles with concentric layered structures were generated from a lamellae-forming poly(styrene-b-isoprene) diblock copolymer using controlled precipitation tetrahydrofuran/water mixture. Chloroform, good solvent for both blocks, was used to swell and anneal the nanoparticles suspended in aqueous media. The three-dimensional morphologies of particles reconstructed by transmission electron microtomography throughout process annealing. A transition lamellae PI cylinders PS matrix occurred...

The creasing instability of elastomer films under compression is studied by a combination experiment and numerical simulation. Experimentally, we attach stress-free film on much thicker stiffer pre-stretched substrate. When the substrate partially released, uniaxially compressed, leading to formation an array creases beyond critical strain. profile folded surface extracted using confocal fluorescence microscopy, yielding depths, spacings, shapes creases. Numerically, onset development are...

A series of porous block copolymer (BCP) particles with controllable morphology and pore sizes was fabricated by tuning the interfacial behavior BCP droplets in oil-in-water emulsions. synergistic adsorption polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) BCPs sodium dodecyl sulfate (SDS) to surface emulsion droplet induced a dramatic decrease tension generated instability at particle surface. In particular, SDS concentration P4VP volume fraction PS-b-P4VP were key parameters determining...