Fabrication of Polymer Composite Fibers Embedding Ultra-Long Micro/Nanowires

Fabrication of polymer composite fibers embedding ultra-long micro/nanowires via an iterative melt co-drawing and bundling technique is reported in this study. The poly(methyl methacrylate) (PMMA) porous array templates were prepared with section-cutting the PMMA/polystyrene (PS) (shell/core) composite fibers and dissolution of inner PS. The results showed that the PS cores or pores in the PMMA matrix are regularly arranged with hexagonal, and their diameter and spacing exhibits a uniform distribution. Especially, the core diameter can be precisely controlled from millimeter-scale to nanometer-scale by multi-step melt co-drawing. Based on the PMMA porous array templates, the Cu nanowires were successfully prepared by electrochemical deposition. Moreover, to fabricate PMMA ultra-long micro/nanowires, the composite fibers with converse shell/core component of PS/PMMA were initially prepared, and then the outer PS was dissolved. The obtained PMMA micro/nanowires were characterized with smooth complete orientation structure. The study provides an experimental basis for fabricating such polymer composite fibers, micro/nano porous array templates, and micro/nanowires with precise and controllable manner to meet the real application requirements.

A structural polymer for highly efficient all-day passive radiative cooling

All-day passive radiative cooling has recently attracted tremendous interest by reflecting sunlight and radiating heat to the ultracold outer space. While some progress has been made, it still remains big challenge in fabricating highly efficient and low-cost radiative coolers for all-day and all-climates. Herein, we report a hierarchically structured polymethyl methacrylate (PMMA) film with a micropore array combined with random nanopores for highly efficient day- and nighttime passive radiative cooling. This hierarchically porous array PMMA film exhibits sufficiently high solar reflectance (0.95) and superior longwave infrared thermal emittance (0.98) and realizes subambient cooling of ~8.2 °C during the night and ~6.0 °C to ~8.9 °C during midday with an average cooling power of ~85 W/m2 under solar intensity of ~900 W/m2, and promisingly ~5.5 °C even under solar intensity of ~930 W/m2 and relative humidity of ~64% in hot and moist climate. The micropores and nanopores in the polymer film play crucial roles in enhancing the solar reflectance and thermal emittance.

Natural forest-inspired Ag lithiophilic porous arrays grown in the Cu foam hosts with bi-continuous electronic/ionic pathways for highly stable Li metal anodes

A pine forest-inspired superior Li host with high lithiophilicity and bi-continuous electronic/ionic pathway was successfully fabricated by in-situ growth of the needle-branch-like Ag hierarchical porous array onto the skeleton surface...