We report that an exceptionally large volume of highly ordered arrays (single grains) on the order of millimeters in scale can be rapidly created through a unique innate guiding mechanism of brush block copolymers (BBCPs). The grain volume is over 10(9) times larger than that of typical self-assembled linear BCPs (LBCPs). The use of strong interactions between nanoparticles (NPs) and BBCPs enables high loadings of functional materials, up to 76 wt % (46 vol %) in the target domain, while maintaining excellent long-range order. Overall, this work provides a simple method to precisely control the spatial orientation of functionalities at nanometer length scales over macroscopic volumes, thereby enabling the production of hybrid materials for many important applications.

Biological materials have the ability to withstand extreme mechanical forces due to their unique multilevel hierarchical structure. Here, we fabricated a nacre-mimetic nanocomposite comprised of silk fibroin and graphene oxide that exhibits hybridized dynamic responses arising from alternating high-contrast mechanical properties of the components at the nanoscale. Dynamic mechanical behavior of these nanocomposites is assessed through a microscale ballistic characterization using a 7.6 μm diameter silica sphere moving at a speed of approximately 400 m/s. The volume fraction of graphene oxide in these composites is systematically varied from 0 to 32 vol % to quantify the dynamic effects correlating with the structural morphologies of the graphene oxide flakes. Specific penetration energy of the films rapidly increases as the distribution of graphene oxide flakes evolves from noninteracting, isolated sheets to a partially overlapping continuous sheet. The specific penetration energy of the nanocomposite at the highest graphene oxide content tested here is found to be significantly higher than that of Kevlar fabrics and close to that of pure multilayer graphene. This study evidently demonstrates that the morphologies of nanoscale constituents and their interactions are critical to realize scalable high-performance nanocomposites using typical nanomaterial constituents having finite dimensions.

The fracture behavior of glassy polymers is strongly coupled to molecular parameters such as entanglement density as well as extrinsic parameters such as strain rate and test temperature. Here we use laser-induced projectile impact testing (LIPIT) to study the extreme strain rate (≈10 7 s −1 ) puncture behavior of free-standing polycarbonate (PC) thin films. We demonstrate that changes to the PC molecular mass and the degree of plasticization can lead to substantial changes in the specific puncture energy. We relate these changes to the alteration of the entanglement density of the polymer that determines the underlying failure mechanism as well as the size of the deformation zone.

Metallic microparticles can acquire remarkable nanoscale morphologies after experiencing high velocity collisions, but materials science regarding the extreme events has been limited due to a lack of controlled experiments. In this work, collision dynamics and nonlinear material characteristics of aluminum microparticles are investigated through precise single particle collisions with two distinctive substrates, sapphire and aluminum, across a broad range of collision velocities, from 50 to 1,100 m/s. An empirical constitutive model is calibrated based on the experimental results, and is used to investigate the mechanics of particle deformation history. Real-time and post-impact characterizations, as well as model based simulations, show that significant material flow occurs during the impact, especially with the sapphire substrate. A material instability stemming from plasticity-induced heating is identified. The presented methodology, based on the use of controlled single particle impact data and constitutive models, provides an innovative approach for the prediction of extreme material behavior.

We report the directed assembly of quantum dots (QDs) within wellordered photonic nanocomposites using a family of (polynorbornene-graf tpoly(styrene))-block-(polynorbornene-graf t-poly(ethylene oxide)) (PS-b-PEO) brush block copolymers (BBCPs). Cadmium selenide (CdSe) nanoparticles (NPs) modified with 11-mercaptoundecylhydroquinone are selectively incorporated within the PEO domains of the self-assembled BBCPs via strong hydrogen-bonding interactions between the ligands on QDs and PEO brushes of the BBCPs. Wellordered QD arrays were readily created within a periodic lamellar polymer matrix, or one-dimensional photonic crystal, with a widely tunable lattice spacing ranging from 46.2 to up to 145 nm. The loading concentration of the QDs can be up to 30 wt % (15 vol %) while maintaining a well-ordered lamellar morphology, providing an optical gain material platform for the systematic investigation of optical properties. Strong photoluminescence and third harmonic generation from the well-ordered QD arrays were observed via multiphoton excitation using femtosecond (fs) laser light at several optical wavelengths from 700 to 1550 nm.