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The effect of bilingualism on the development of phonological awareness of Chinese children was investigated in 2 studies comparing bilingual speakers of both Cantonese and Mandarin with monolingual speakers of Mandarin. Cantonese-speaking children had developed more advanced onset and rime awareness by 2nd grade as they learned Mandarin in school and became bilingual. Bilingualism seemed to accelerate the development of phonological awareness. But the advantage had mostly disappeared by 4th grade. On the other hand, in the 1st grade, Cantonese-speaking children had more advanced tone awareness than Mandarin-speaking children. This was likely because Cantonese has a more complicated tone system than Mandarin.

Since the first discovery of spontaneous emulsification, the process has remained uncontrollable for centuries leading to unstable emulsion droplets with limited uses. Herein, by in situ observation it was found that uniform water-in-oil (W/O) nanoemulsion droplets can be spontaneously formed and selforganized during solvent evaporation. Amphiphilic bottlebrush block copolymers are strongly adsorbed at the water/oil interface to stabilize the droplets, and their rod-like molecular conformation enables good control of the droplet spherical curvature. After solvent removal, solidified thin films or microparticles with hexagonal closest packed nanopore arrays are produced in one-step templated by the ordered W/O emulsions. The pore diameter is precisely tunable in a wide range (160 ≤ D ≤ 395 nm) by changing the spherical curvature of the water droplets dependent on the degree of polymerization of the bottlebrush block copolymer (BBCP) (89 ≤ DP ≤ 151). The well-ordered porous structures give rise to full-spectrum structural colors. This work provides a general method for scalable production of well-ordered porous materials with greatly reduced energy consumption.

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This manuscript describes the versatility of highly directional, noncovalent interactions, i.e., quadruple hydrogen bonding (QHB), to afford novel polyurea segmented supramolecular polymers for melt extrusion three-dimensional (3D) printing processes. The molecular design of the polyurea elastomers features (1) flexible polyether segments and relatively weak urea hydrogen-bonding sites in the soft segments to provide elasticity and toughness, and (2) strong ureido-cytosine (UCyt) QHB in the hard segments to impart enhanced mechanical integrity. The resulting polyureas were readily compression-molded into mechanically-robust, transparent, and creasable films. Optimization of polyurea composition offered a rare combination of high tensile strength (95 MPa), tensile elongation (788% strain), and toughness (94 MJ/m3), which are superior to a commercially available Ninjaflex elastomer. The incorporation of QHB facilitated melt processability, where hydrogen bonding dissociation provided low viscosities at printing temperatures. During cooling, directional self-assembly of UCyt QHB facilitated the solidification process and contributed to part fidelity with the formation of a robust physical network. The printed objects displayed high layer fidelity, smooth surfaces, minimal warpage, and complex geometries. The presence of highly directional QHB effectively diminished mechanical anisotropy, and the printed samples exhibited comparable Young’s moduli along (x–y direction, 0°) and perpendicular to (z-direction, 90°) the layer direction. Remarkably, the printed samples exhibited ultimate tensile strains approaching 500% in the z-direction prior to failure, which was indicative of improved interlayer adhesion. Thus, this design paradigm, which is demonstrated for novel polyurea copolymers, suggests the potential of supramolecular polymers with enhanced mechanical performance, melt processability, recyclability, and improved interlayer adhesion for melt extrusion additive manufacturing processes.