Controlled Kinematics for 2D Microfilament Weaves

In the textile industry, complex techniques, such as weaving, knitting, bonding and felting, are used to produce fabrics by controlling the kinematics of long, flexible filaments. Achieving similar kinematic control to produce similar assemblies at smaller sizescales is significantly challenging. Barber et al. (Nat. Comm., 2023) reported an approach to autonomously link microfilaments into bundles. However, assembly of microfilaments into 2D structures, such as weaves, requires a more ordered and precise regulation to intertwine filaments at arbitrary angles. Inspired by the mechanism of the loom, we proposed to use polydimethylsiloxane (PDMS) microfilaments and composite filaments of that incorporating iron (III) oxide (Fe₃O₄) magnetic particles to form plain woven multifilament assemblies. Warp PDMS microfilaments are fabricated through nanoimprint lithography. Upon releasing in water, those filaments spontaneously coil driven by interfacial tension difference between the top and bottom. Transitioning between liquids with varying surface tensions, different curvatures is controlled reversibly, compared to the irreversible curvature change by plasticization (Barber et al. Adv. Mat., 2018). For weft, low viscosity PDMS prepolymers are cured within a microfluidic device shaped like a sperm, with magnetic particles concentrating in the head. The body of the ‘sperm’ will be served as weft, after passing underneath the slits opened by warp in the magnetic field. The ability to create 2D woven microfilament assemblies opens the door for creating ultra-thin membranes and conductive materials with advantageous combinations of stretching and bending properties.