Moisture-sensitive torsional cotton artificial muscle and textile*

Abstract

Developing moisture-sensitive artificial muscles from industrialized natural fibers with large abundance is highly desired for smart textiles that can respond to humidity or temperature change. However, currently most of fiber artificial muscles are based on non-common industrial textile materials or of a small portion of global textile fiber market. In this paper, we developed moisture-sensitive torsional artificial muscles and textiles based on cotton yarns. It was prepared by twisting the cotton yarn followed by folding in the middle point to form a self-balanced structure. The cotton yarn muscle showed a torsional stroke of 42.55 °/mm and a rotational speed of 720 rpm upon exposure to water moisture. Good reversibility and retention of stroke during cyclic exposure and removal of water moisture were obtained. A moisture-sensitive smart window that can close when it rains was demonstrated based on the torsional cotton yarn muscles. This twist-based technique combining natural textile fibers provides a new insight for construction of smart textile materials.

Wool Can Be Cool: Water‐Actuating Woolen Knitwear for Both Hot and Cold

“…Equation (13) indicates that the loop distance in the wale direction of the knitted fabric increases with an increase in loop length and a decrease in the diameter of the plied yarns. It can also be deduced that the dimensional changes in the wale direction are larger than those in the course direction with an increase in l arc and a decrease in r py , as observed from Equations (13) and (14), which is consistent with the experimental results ( Figure S7, Supporting Information). Moreover, the porosity of the knitted fabric can be expressed as…”

“…Considering the knitted fabric to be a two-dimensional topological network, the knitted loop structure and a unit of the knitted fabric are shown in Figure 6. The loop distance between adjacent knitted loops along the wale and course directions can be expressed as Equations (13) and (14), respectively. Here, l arc is the length of the arc in the loop (Figure 6).…”

“…Moisture-sensitive natural cotton yarn smart muscles with expansion-contraction behavior have recently been proposed for the fabrication of thermoregulatory clothing. [14] However, the proposed techniques require a high degree of twist and plying approach, which makes the raw materials incompatible with conventional textile processing.…”

Recent Advances in Twisted‐Fiber Artificial Muscles

“…Reproduced with permission. [ 37 ] Copyright 2020, Chinese Academy of Sciences.…”

“…The Liu and co‐workers developed cotton artificial muscle fibers actuated by moisture and used it for smart fabrics. [ 37 ] The humidity‐responsive cotton artificial muscle fibers were constructed from twisted and plied cotton fibers, which used torque‐balanced fiber structures to avoid the need for torsional tethering. The cotton artificial muscle fiber produced a completely reversible torsional stroke of 42.55° mm −1 , which was at the same level as that of the water‐actuated coiled CNT fiber (61.30° mm −1 ).…”