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A Transparent Membrane for Active Noise Cancelation
Author(s) -
Rothemund Philipp,
Morelle Xavier P.,
Jia Kun,
Whitesides George M.,
Suo Zhigang
Publication year - 2018
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201800653
Subject(s) - materials science , membrane , self healing hydrogels , acoustics , sound transmission class , absorption (acoustics) , noise (video) , electrical impedance , elastomer , reflection (computer programming) , composite material , computer science , physics , genetics , image (mathematics) , artificial intelligence , polymer chemistry , electrical engineering , biology , programming language , engineering
A method for active noise cancelation that uses an optically transparent membrane is described. The membrane consists of a prestretched hydrophobic elastomer, attached to a rigid frame and sandwiched between two hydrogels swollen with an aqueous solution of salt. The elastomer functions as a dielectric, and the hydrogel functions as an ionic conductor. When the two hydrogels are subjected to a sinusoidal voltage, the membrane generates sound. A linear model for the reflection, transmission, and generation of sound by the membrane in an impedance tube is presented and validated. Active noise cancelation is demonstrated using the linear model and feedforward control. Compared to passive sound absorption, the sound transmission loss across the membrane is improved with active control from an average value of 7 dB to an average value of 16 dB. The transparent membrane may be used to cancel noises through a window, while maintaining its transparency.