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In the advancement of paper-based microfluidic devices, it is reported that the two-ply channel transports fluid noticeably faster than traditional single-ply channels. In this work, the capillary flows in two-ply channels, consisting of a gap of width w between two porous sheets with porosity ε and thickness d, are investigated through many-body dissipative particle dynamics simulations. The advancing meniscus varies with position, characterized by the penetration lengths in the gap (Lg), the porous sheet (Lp), and the maximum value (Lmax). Lmax is always located within the porous sheet but near the gap. The time evolution of the penetration lengths can be described by Washburn's expression, L2 = (S)t, and the imbibition rates Sp, Sg, and Smax depend on ε, d, and w, differing from each other. Two distinct imbibition characteristics are identified: Sg > Sp for low porosities and Sg < Sp for high porosities. Both Sg and Sp decrease with d but increase with w. As ε increases, a minimum of Smax occurs due to the synergistic competition between Sp and Sg. Compared to the single-ply channel, which consists of a single porous sheet, the imbibition rate of the two-ply channel is significantly enhanced by at least four times due to side-imbibition from the gap (acting as a reservoir) toward the porous sheet. [ABSTRACT FROM AUTHOR]

ABSTRACT Three random copolymers comprised pendant styrene and 4-(1-pyrenyl)-styrene (PyS) moieties in different molar ratios (21.4:1 ( P1), 3.9:1 ( P2), and 1.4:1 ( P3)) were synthesized and employed as charge storage polymeric electret for nonvolatile organic field-effect transistor (OFET) memory application. The impact of varying the molar ratio in side-chain electron-donating pyrene moieties on the thermal, optical, photophysical, electrochemical, and electrical properties of the resulting pendant copolymers was evaluated to establish structure-property relationship. The OFET memory with P3 electret layer exhibits a largest memory window of 41.8 V, long retention time of 104 s with memory ratio of 105, and stable reversibility of at least 100 cycles due to enhanced field-induced holes trapping ability from higher PyS composition ratio. Therefore, polymer electret with pendant functional moieties shows potential for use as trapping layer in OFET memory devices. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 910-917 [ABSTRACT FROM AUTHOR]