Coiled actuator system and method

Abstract

A method for making a coiled actuator fiber is provided. The method includes twisting a fiber to create a twisted fiber (100), wrapping the twisted fiber around a core (510) to create a coil in the twisted fiber, and removing at least a portion of the core to create a coiled actuator fiber. In some embodiments, the fiber can be a yarn having one or more fibers or a fiber including a single elongated element. In some embodiments, a portion of the core includes a removable sacrificial portion. The removable sacrificial portion can be dissolvable in a solvent or physically removable. In some embodiments, the core further includes an indissolvable portion that is indissolvable, and creating the coiled actuator can include removing the sacrificial portion by treating the twisted fiber over the core to remove the sacrificial portion and leaving the indissolvable portion.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 62 / 483,839, entitled "COILED ACTUATOR SYSTEM AND METHOD," filed April 10, 2017, which is incorporated herein by reference in its entirety for all purposes.

[0002] This application is also related to U.S. patent application Ser. No. XX / XXX,XXX, entitled "COILED ACTUATOR SYSTEM AND METHOD" filed on April 10, 2018 and having Attorney Docket No. 0105198-019US0, and to U.S. patent application Ser. No. 15 / 160,439, entitled "SYSTEM AND METHOD FOR THERMALLY ADAPTIVE MATERIALS," filed on May 20, 2016, which are hereby incorporated by reference in their entireties for all purposes.

[0003] (Government Rights) This invention was made with United States Government support under DE-AR0000536 awarded by the United States Department of Energy. The United States Government has certain rights in this invention. [Brief description of the drawings]

[0004] [Figure 1] FIG. 1 is a diagram of a twisted fiber, filament, or yarn showing the fiber bias angle (α fiber).

[0005] [Diagram 2] FIG. 1 is a diagram of a twisted and coiled fiber or yarn showing the fiber bias angle (α fiber), coil bias angle (α coil), coil diameter (D), and fiber diameter (d).

[0006] [Diagram 3]3a and 3b are diagrams of two examples of coiled fibers or yarns with different coil bias angles.

[0007] [Figure 4] 4a and 4b are diagrams of another example of a twisted fiber or yarn created by removing a sacrificial layer to increase the distance or spacing between the coils.

[0008] [Diagram 5] 5a and 5b show further examples of coiled fibers or yarns made by wrapping a twisted fiber or yarn around a mandrel or core material, such as another fiber or yarn, to produce a released coiled fiber or yarn after the mandrel or core material is removed.

[0009] [Figure 6] Figure 6a shows a further example of a coiled fiber or yarn made by wrapping a twisted fiber or yarn around a core material that includes a central core covered with a removable material, and Figure 6b shows an example of a coiled fiber or yarn made after dissolving or reacting the removable material, leaving the core material in the center of the coiled fiber or yarn.

[0010] [Figure 7] Figure 7a shows an example of a twisted fiber or yarn that has been coiled around a mandrel or core such that the fiber or yarn does not contact its nearest neighbors, and Figure 7b further shows the resulting coiled fiber or yarn after removing the mandrel or core.

[0011] [Figure 8]Figure 8a shows another example of a twisted fiber or yarn that has been coiled around a mandrel or core along with a second fiber or yarn that acts as a spacer for the twisted fiber or yarn, and Figure 8b shows the coiled fiber or yarn that is produced after removing the mandrel or core and the spacer fiber or yarn.

[0012] [Figure 9] Figure 9a shows two twisted fibers or yarns coiled around a mandrel or core, and Figure 9b shows two coiled fiber or yarn actuators created after removing the mandrel or core of Figure 9a. The two coiled actuators are shown nested within each other.

[0013] [Figure 10] 1 illustrates an example of a twisted fiber manufacturing process including process monitoring and feedback.

[0014] [Figure 11] FIG 11a shows an example of a fiber coiling system including a fiber source spool that supplies fiber to a take-up spool that receives and takes up the fiber. FIG 11b shows the fiber coiling system of FIG 11a with the coil origin region moved toward the take-up spool compared to FIG 11a. FIG 11c shows the fiber coiling system of FIG 11a with the coil origin region moved toward the source spool compared to FIG 11a.

[0015] [Figure 12] Figure 12a is a diagram of a kink or typical snare that can occur in a fiber or yarn through twist insertion, and Figure 12b is a diagram of a cylindrical snare that can be created in a fiber or yarn through twist insertion.

[0016] [Figure 13]Figure 1 shows an environmentally responsive coiled fiber actuator. Microscope images show coils of similar geometry fabricated by two different methods. Scale bar length is 0.5 mm. [Figure 14] Figure 1 shows an environmentally responsive coiled fiber actuator. Microscope images show coils of similar geometry fabricated by two different methods. Scale bar length is 0.5 mm.

[0017] [Figure 15] Figure 15a shows an example embodiment of a bimorph including one or more coiled fiber actuators, and Figure 15b shows an example embodiment of a bimorph including one or more coiled fiber actuators. [Figure 16] Figure 16a shows an example embodiment of a bimorph including one or more coiled fiber actuators, and Figure 16b shows an example embodiment of a bimorph including one or more coiled fiber actuators. [Figure 17] Figure 17a shows an example embodiment of a bimorph including one or more coiled fiber actuators, and Figure 17b shows an example embodiment of a bimorph including one or more coiled fiber actuators. [Figure 18] FIG. 18 shows an example embodiment of a bimorph that includes one or more coiled fiber actuators.

[0018] [Figure 19] 1 shows effective coefficient of linear thermal expansion (CTE) data for over 200 example twisted and coiled homochiral fiber actuators with various coil index values ​​(C). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] It should be noted that the figures are not drawn to scale, and that elements of similar structure or function are generally designated by similar reference numerals throughout the figures for illustrative purposes. It should also be noted that the figures are intended only to facilitate the description of the preferred embodiments. The figures do not illustrate all aspects of the described embodiments and do not limit the scope of the present disclosure.

[0020] In various embodiments, a coiled actuator ("artificial muscle") can be created through a twist insertion process. For example, a fiber can be twisted until it coils. In another example, a fiber can be twisted until it nearly coils and then wrapped around a mandrel or fiber or yarn core. Although various examples discussed herein refer to fibers, it should be clear that various embodiments can include any suitable elongated element, including fibers, filaments, ribbons, threads, wires, and the like. Additionally, as used herein, "fiber" can encompass any such elongated element, including a thread including one or more fibers or other elements, a fiber including a single elongated element, and the like. Thus, unless otherwise indicated by context, the term "fiber" should be construed to broadly encompass any such elongated element or elements.

[0021] In some embodiments, the coiled actuator fibers discussed herein can be used to actuate a textile fabric. For example, such textile fabrics can be used to create apparel that responds to various types of environmental conditions, including temperature, moisture, humidity, and the like. In some implementations, the textile fabric can have a minimal loading and / or can need to be actuated at or near body temperature, and various embodiments can be configured to provide the desired operation under such operating conditions. Further embodiments can be configured for a variety of other suitable purposes or applications, and examples relating to configurations for use by a human or animal user should not be construed as limiting the many applications of the actuators disclosed herein.

[0022] Various embodiments may have many advantages for some applications or implementations For example, actuators of some embodiments may include greater thermal response values ​​for actuators made using convenient manufacturing techniques, where the actuators have controlled coil contact temperatures and thermal response ranges.

[0023] Coiled thermal fiber actuators or coiled thermal yarn actuators according to various embodiments can be fabricated through coiling by twisting until they become kinked or entangled (self-coiling or coiling by twisting), through coiling (coiling by wrapping) around a mandrel or other suitable material that serves as a core around which a fiber or fibers can be wrapped, or through other suitable methods. In various examples, such cores can be partially or fully removable, including removal via dissolution, as discussed in more detail herein.

[0024] In some instances, conventional yarn making equipment such as spinning or twisting machines cannot reliably produce fiber or yarn actuators of desired controlled geometry that are coiled by twisting. The production of such yarns can be sensitive to variables such as ambient temperature, ambient humidity, input filament crystallinity and orientation, friction, input filament defects, spindle speed, feed or take-up speed variations, input filament diameter, yarn tension, and the like.

[0025] However, as discussed in more detail herein, in various embodiments, careful balancing of yarn tension, yarn feed rate, twist insertion / m, package winding speed, flyer (or ring and traveler) rotation speed during yarn spinning, etc., can result in highly twisted or coiled actuators with controllable geometry. To compensate for variations in the above variables, one or more of these parameters may need to be changed or adjusted during production, but some conventional manufacturing machines do not allow such parameters to be changed during production. Furthermore, parameters of one position or spindle may need to be changed differently than parameters of another position or spindle, which may not be possible in some systems when several positions are driven by a common drive. Thus, a novel machine that provides such functionality is disclosed herein.

[0026] Examples of methods for inserting twist into filament yarns or fibers (either monofilament or multifilament) include ring twisting, friction spinning, double twist, etc. Ring spinning can be a process that uses the action of a guide called a traveler that circulates freely around a ring to insert twist and simultaneously wind the formed yarn onto a bobbin. In some manufacturing environments, the spindles can be driven using a common belt drive system. The amount of twist inserted into the fiber can be determined by the speed of the yarn exiting the supply roll and the rotational speed of the spindle. The rotational speed of the traveler (also known as the follower) can be a speed that can slow the rotational speed of the spindle due to friction and tension. The difference in the rotational speed of the traveler and the spindle allows the yarn to be wound onto a bobbin. Flyer spinning and roving may follow a similar principle to ring spinning, where a flyer rotates around a rotating spindle at a different speed, resulting in twist insertion and winding of the yarn. In double twist, the twist level can be controlled by setting the yarn feed speed and the spindle rotation speed, or the take-up reel rotation speed and the spindle rotation speed. The motors controlling the yarn feed, spindle and / or take-up reel at different locations of the manufacturing apparatus may be driven by a common belt drive system for economic or other purposes.

[0027] Winding the highly twisted fiber around a mandrel or other core, such as another fiber or yarn, in some embodiments provides a means to obtain coils with larger diameters, larger openness, and increased coil spring index values, as well as a method for thermal responsiveness. However, in some instances, mandrel winding may not be well suited for mass production due to the challenge of removing the mandrel from the coiled fiber or yarn actuator being fabricated. Mandrel winding may be better suited for mass production in some instances where the process involves a short mandrel, perhaps a mandrel tapered at one end, that can hold a fiber, fibers, or yarn on one side to feed it for winding around the mandrel. As the fiber coils and advances around the mandrel, it can come off the end of the mandrel and be wound onto a cone or drum. For fiber or yarn actuators, in some embodiments, the twisted fiber, fibers, or yarns used in the wrapping or winding process are set (by heat, steam, chemical or mechanical treatment) prior to wrapping or winding, but in some embodiments may be set after the wrapping or winding process. In some examples, as described in more detail herein, a sacrificial material can be used as a core in the process of coiling the fiber or yarn through wrapping or winding around the sacrificial material, which can be subsequently removed through physical means, dissolving, melting, washing, chemical methods, etc.

[0028] One approach that can address coil shape (e.g., thermal responsiveness) and / or coil spacing (e.g., operating temperature range) can include the use of sacrificial materials. In one such embodiment, a coextruded multicomponent fiber, such as a core-sheath structure, can be twisted and coiled (e.g., coiled by twist insertion or through winding around a mandrel or other core, and the coiled actuator can be selectively untwisted) to form a thermal actuator. By melting or chemically reacting portions of the sheath and removing the sheath portions, the spring index of the coil can be improved while at the same time increasing the coil spacing in some instances. In some instances, removal of the sheath (or sheaths) can be done either before or after heat setting.

[0029] Some twisting techniques, spinning techniques, twisting machines and spinning machines may be limited in their rotation speed by the need to rotate the yarn or fiber package. False twisting techniques can overcome these practical rotation speed limitations by spinning a much smaller mass, but in various examples, such methods cannot insert true twist and cannot allow for the production of highly twisted and coiled fibers and yarns with the desired properties. In some examples, the high rotation speed of some false twisting techniques can be utilized in the twisting or coiling process. By undoing the imparted twist on the side where the fiber or yarn is fed to the twisting machine, the opposite side of the twisting unit can impart true twist and not just remove the imparted twist on the opposite side of the twisting unit. Undoing the twist can be done on the yarn feed side of the machine through two similar approaches. One approach is to feed individual short fibers to the unit and form the yarn at the site of the twisting unit, similar to open-end spinning. In various examples, the machine can form the yarn at the rotation site so that large masses do not need to be spun and false twisting does not occur. A second approach is to twist the extruded fiber as part of an in-line process, where the twist is released near the extrusion site in a melt, gel or solution by molecular escape.

[0030] FIG. 1 shows an example 100A of a twisted fiber 100, in which the fiber bias angle (α 繊維 ) is shown. The level of twist in fiber 100, in this example represented by dashed line 105, is twisted throughout fiber 100. In various embodiments, the twist level can be observed and determined directly from fiber 100 through inspection under a microscope. As shown in FIG. 1, the fiber bias angle α 繊維 can be determined by measuring the angle between the twist observed at the fiber surface and the axial direction of the fiber 100. For untwisted fibers, the fiber bias angle will be 0° in various instances.

[0031] Fibers, filaments, and yarns can be twisted during processing and end-use application. The fiber and yarn actuators described herein can have what are described as "high twist levels" (or "highly twisted"), and in some examples, these actuators can have a fiber bias angle α in some embodiments. 繊維 20° or more, and in a further embodiment the fiber bias angle α 繊維 In some instances, "highly twisted" or having a "high twist level" may include an amount of twist sufficient to provide a fiber bias angle α between 25° and 50°. 繊維 The amount of twist can include an amount of twist that causes the fiber bias angle to be 10° or more, 15° or more, 20° or more, 25° or more, 30° or more, 35° or more, 40° or more, 45° or more, 50° or more, or 55° or more. When twist is inserted into a fiber or yarn, increasing the fiber bias angle, the fiber or yarn tends to snarl. The onset of this snarl depends on many variables, including environmental conditions, the material, the processing history of the material, and the tension under which the fiber or yarn is subjected. The fiber or yarn is generally twisted at a fiber bias angle α of 10° or more, 15° or more, 20° or more, 25° or more, 30° or more, 35° or more, 40° or more, 45° or more, 50° or more, or 55° or more. When twist is inserted into a fiber or yarn, increasing the fiber bias angle, the fiber or yarn tends to snarl. The onset of this snarl depends on many variables, including environmental conditions, the material, the processing history of the material, and the tension under which the fiber or yarn is subjected. 繊維 When the fiber bias angle α is greater than 40°, and in some cases around 45°, tangling often occurs. 繊維It is beneficial to create highly twisted fibers or yarns with twist angles of 30°-40°, which, by wrapping around a core, are less likely to become entangled when creating highly twisted filaments that can be used to create coiled fiber actuators.

[0032] The conditions for producing such highly twisted fibers 100 may vary depending on environmental conditions, material identity, material processing history, and fiber diameter, and in some instances, the larger the fiber diameter, the greater the fiber bias angle α 繊維 In yarns, the effective fiber bias angle α 繊維 can be understood to be the angle of the filaments at the surface of a twisted or highly twisted yarn.

[0033] For fiber materials such as nylon, polyester, etc., the coefficient of thermal expansion (CTE) value may be around 0.05 mm / m / °C in some examples, and about 0.1 mm / m / °C or less in further examples. In the illustrated fiber or sheet, the orientation of the polymer chains can result in anisotropic properties, and the CTE value may drop by a factor of 10 or more in the stretch direction in some examples, or may even be negative in further examples. However, the thermo-mechanical response of the fiber 100 can be effectively amplified in some examples through the use of a coil or spring structure. Commonly used fibers and yarns can be coiled or "tubularly entangled" through the insertion of high twist levels to create coiled fiber thermal actuators according to some embodiments that can be referred to as "artificial muscles" (essentially fibers or yarns that are coiled like a spring so that they have excellent, i.e., very high, thermal expansion properties).

[0034] FIG. 2 is a diagram of an example 100B of a twisted and coiled fiber 100, showing the fiber bias angle (α 繊維 ), coil bias angle (α コイル), coil diameter (D), and fiber diameter (d) are shown. The fiber 100 of FIG. 1 is shown in a coiled configuration that defines a cavity 220 extending inside the coiled fiber 100. In this example, adjacent coil portions 240 of the coiled fiber 100 are spaced apart to define a space 260 between adjacent coil portions 240. For example, the first coil portion 240A and the second coil portion 240B of the coiled fiber 100 define a first space 260A, and the second coil portion 240B and the third coil portion 240C of the coiled fiber 100 define a second space 260B. In this example, the first space 260A and the second space 260B define a continuous space 260 extending inside the coiled fiber 100. In a further example, as described in more detail herein, the coil portions 240 of the coiled fiber 100 can be connected such that some or all of the spaces 260 between the portions 240 of the coiled fiber 100 are eliminated (e.g., FIG. 3b).

[0035] As shown in FIGS. 1 and 2, the twisted fiber 100 has a fiber bias angle α 繊維 For a fiber 100 that is twisted to coil, the fiber bias angle α 繊維 can be determined by the materials and process conditions used to form the coil. However, in some embodiments, this does not determine the optimal or desired fiber bias angle α for a particular targeted temperature response. 繊維 By forming a coil through winding or wrapping around a mandrel or other core, the desired fiber bias angle α 繊維 In some embodiments, a coil can be formed from one or more highly twisted fibers 100 such that a desired fiber bias angle α 繊維 can be 30° to 50°, and in some instances, more preferably 35° to 45°.

[0036] The coil diameter (D) and fiber diameter (d) can be used to calculate the coil spring index (C). For example, the spring index (C) can be defined in spring mechanics as C=D / d, where d is the fiber diameter and D is the nominal diameter of the coil as measured through the fiber centerline as shown in FIG. 2. A coil or spring with a high spring index (C) can have a larger diameter as well as a wider opening, while a coil with a lower spring index (C) can approach a tightly wound coil with a smaller diameter. Properties such as the effective coefficient of thermal expansion (CTE) and stiffness (e.g., modulus of elasticity) of a coiled actuator can depend on the geometry of the coil (e.g., fiber bias angle α). 繊維 Including the fiber structure, the spring index C and the coil bias angle α コイル (Also contributes to the spring force.) In some embodiments, by varying the spring exponent (C), the actuation stroke and / or stress may be tunable to desired parameters.

[0037] In various embodiments, the thermal response of the coiled fiber 100 can be controlled through the geometry of the coil 100. In some applications, it is beneficial to maximize the thermal response of the coiled fiber 100, which in some instances may require a large coil diameter (D) (e.g., relative to the fiber diameter (d)). In some instances, coiled fibers 100 formed without winding on a mandrel, yarn, fiber, or other core may be limited to small coil diameters (D) and small values ​​of coil spring index (C). To overcome this limitation with fiber and yarn actuators made by self-coiling, to achieve a large coil diameter (D) as well as a coil spring index (C) substantially greater than about 1.7, greater than 2.0, or greater than 2.5 and an effective coefficient of thermal expansion (CTE) of -2 mm / m / K or greater, the as-formed coils of some embodiments are untwisted (i.e., twisted in the opposite direction to the twist insertion direction that caused the coiling) to remove excess residual torsional and residual compressive mechanical stresses. This untwisting can change the shape of the coil and increase the coil diameter, although in various embodiments it is not necessary to perform this operation until the coil is removed to achieve the desired results. In some embodiments, the maximum coil diameter (D) is achieved by controlled untwisting under a low load (e.g., ≦50% of the load used during the coiling step) or even near zero load (e.g., ≦10% of the load used during the coiling step, negligible tensile load, etc.) rather than the tensile load that was suitable for the coiling process. In some embodiments, untwisting can be used to affect the coil spring index (C) and / or shape of the coil created through the winding process.

[0038] Coil bias angle (α コイル The coil bias angle (α) can be determined by measuring the angle between the axial direction of the twisted fiber 100 and an imaginary line perpendicular to the direction in which the coiled fiber 100 extends. When the coiled fiber 100 is stretched like a spring, the coil bias angle (α コイル ) can be increased, and for a given coiled fiber 100, fully compressing the coiled fiber 100 until the coil portions 240 of the fiber 100 abut one another results in a coil bias angle (α コイル) can reach its minimum value.

[0039] In addition to the coil spring index (C), which can reflect the overall coil diameter (D) relative to the fiber diameter (d) of the fiber 100 constituting the coil, the coil bias angle α コイル can be a measure of the structure of the coil that is related to the coil's properties. When the coil is formed under the influence of excessive or high twist (twist coiling), the sections 240 of the coiled fiber 100 physically contact each other, and each coil section 240 can touch its neighboring coil sections 240. When such coils are optimally stacked, the coil bias angle α コイル , and maximizing responsiveness to changes in temperature or other environmental parameters. In some examples, when the coiled fiber 100 is physically stretched and the coil is elongated to create spaces 260 between the coil portions 240, the coil bias angle α コイル may increase and temperature responsiveness may decrease.

[0040] Various coiled fiber actuators that are coiled through twist insertion (twist-induced coiling) have coil bias angles α コイル However, in some examples as described herein, forming a coil by winding around a core (coiling by winding) can result in a coil with a minimal potential coil bias angle α コイル We can provide some additional control over the coil spring index (C) versus the coil bias angle α コイル reaches a minimum (adjacent coils touch each other) or the coil bias angle α コイル In some applications, it may be beneficial to maximize the thermal response of the actuator, and the coil bias angle α コイル The coil bias angle α コイルControl of may also involve control of the coil-to-coil contact temperature and the environmental responsiveness range of the actuator.

[0041] As in FIG. 1, the level of twist in fiber 100 is represented by dashed line 105, with fiber 100 being twisted throughout. At the bottom of the diagram in FIG. 2, twisted fiber 100 is shown in cross section, with dashed arrows representing the direction of twist in twisted fiber 100. As shown in the example of FIG. 2, the twist is in the Z direction, as in the coil, so the coiled fiber 100 can be defined as homochiral. Further examples of coiled fiber 100 can have any suitable chirality. Near the top of the diagram, the fiber or coil is shown in dashed lines to indicate that the fiber 100 coil can continue for any length. Thus, in various embodiments, the coiled fiber 100 as discussed herein can have any suitable length. The shaded portion of the twisted fiber represents the portion of the coiled fiber 100 that is located toward the back of the illustrated page.

[0042] 3a and 3b show the example coiled fiber 100B of FIG. 2 in two different configurations with different coil bias angles. The spring index (C) of the coiled fiber 100 of FIG. 3a is comparable to the spring index of the coiled fiber 100 of FIG. 3b. In various examples, the coiled fiber 100B of FIG. 3b can be stretched, such as through mechanical stress or a temperature change to expand, into a configuration similar to that of the coiled fiber of FIG. 3a. Similarly, the coiled fiber 100B of FIG. 3a can be compressed, such as through mechanical stress or a temperature change to compress, into a configuration similar to that of the coiled fiber of FIG. 3b. In some embodiments, the example coiled fiber 100 of FIG. 3a and 3b is homochiral, and a decrease in temperature can cause the coiled fiber 100 to linearly expand.

[0043] 4a and 4b illustrate the use of a sacrificial material 410 to control the coil shape of the coiled fiber 100. For example, FIG. 4a illustrates a core coiled fiber 100 (i.e., an islands-in-the-sea fiber) having a shell 410, which can be a removable material. For example, in some embodiments, the shell 410 can be removable (e.g., via washing, chemical dissolution, etc.), and the resulting coiled fiber 100 can have additional spaces between the coils of the fiber 100 and / or different coil index values, as shown in the example of FIG. 4b. For example, as shown in FIG. 4b, spaces 260 can be provided between each portion 240 of the coiled fiber 100. Although the coiled fiber 100 of FIGS. 4a and 4b does not show any twist in the fiber 100, in further embodiments, the coiled fiber 100 can include any suitable amount of twist.

[0044] 5a and 5b illustrate the use of a sacrificial core 510 to control the coil shape, showing the twisted fiber 100 wrapped around the core 510, which can define the inner diameter of the coiled fiber 100. The dashed lines of the core 510 indicate that the core 510 can have any suitable length. The core 510 can be disposed within the cavity 220 of the coiled fiber 100 and can include elements including mandrels, filaments, threads, and the like. In various embodiments, the core 510 as shown in FIG. 5a can be removed (e.g., physically, chemically, or in other suitable manner) to result in an unfixed coiled fiber 100 as shown in FIG. 5b. In one embodiment, the central core 510 can include a filament or thread that includes a soluble polymer, such as polyvinyl alcohol, ethylene vinyl alcohol, and the like, that can be dissolved in water or other solvents at any suitable temperature, such as room temperature, 40° C., 60° C., 80° C., high or low temperatures.

[0045] In fabrication methods in which one or more twisted fibers 100 are wound around a sacrificial core 510, the core 510 does not need to be completely removed, and in some cases it may be desirable to leave a portion of the core 510. Remaining a portion of the core 510 within the cavity 220 of the coiled actuator fiber 100 can be beneficial in many other ways, including when the remaining material is electrically conductive (e.g., metal, composite, organic, etc.) allowing the material to be heated, or when the material is extensible (e.g., due to its chemistry, mechanical structure, etc.) and can be easily stretched linearly, but improves the strength of the material against bending or buckling.

[0046] Illustratively, a water soluble fiber can be used as the core 510 in a covered yarn, where a covering fiber or fibers are twisted before or during a winding operation that constitutes a winding process on the core 510, and the core 510 can be removed through a washing process after the wound fiber 100 is set. Numerous materials are suitable for use as the sacrificial core 510, such as water soluble polymer filaments or yarns, organic soluble polymer filaments or yarns, or filaments or yarns that readily dissolve or decompose in the presence of acids, bases, oxidizing agents, reducing agents, or other chemical reagents.

[0047] As a non-limiting example, an "islands in the sea" yarn can be used as a sacrificial core 510, and when the "sea" component of the yarn is washed out, the fine fiber yarn can remain inside the cavity 220 of the coil actuator. These fibers can be useful for moisture management or limiting the range of motion of the fiber actuator. In the case of a homochiral fiber actuator, at the coil contact temperature, an effective minimum length can be achieved (i.e., when some or all of the portions 240 of the coiled fiber 100 abut such that the space 260 is partially or completely eliminated. A homochiral fiber actuator will have physical space between its coils at temperatures below the coil contact temperature), but as the temperature is reduced and the coil expands, the presence of one or more fibers running through the cavity 220 of the coiled fiber 100 can limit the extent of motion of the coiled fiber 100. "Islands in the sea" yarns can be made from multicomponent extruded fibers where at least one component is soluble or otherwise removable, allowing fine features to be formed, including "islands" of non-sacrificial material within a "sea" of sacrificial material. At some point during processing, the sacrificial material can be removed, leaving behind "islands," which can be fine-feature fibers that are difficult to process at high speeds on some machines if not protected by the "sea" of sacrificial material.

[0048] For example, Figures 6a and 6b show another example 100E of a coiled fiber 100 that can be made by wrapping a twisted fiber 100 around a core 510 that includes a removable shell material 610 and an inner material 620. In the example of Figure 6a, the core 510 can include an outer layer, or shell material 510, that can be soluble or otherwise removable, and after the twisted fiber 100 is wrapped around the core 510, the removable shell material 610 can be dissolved or otherwise removed, freeing the coiled fiber 100 to move away leaving behind a reduced central core inner material 620, as shown in Figure 6b. While this remaining core material is shown as one strand of one material, in some embodiments it can include multiple materials and / or multiple strands.

[0049] For actuators including one or more coiled fibers 100 made by winding, including coiled fibers 100 with or without spaces 260 between portions 240 of the coiled fiber 100, the coil spacing can be controlled through controlling the number of twists or wraps per meter around the core 510. For example, FIG. 7a shows another example 100F of a twisted fiber 100 coiled around a core 510 (e.g., a mandrel or central core having one or more materials, as discussed herein) such that each fiber yarn coil portion 240 does not contact its nearest neighbors, such that spaces 260 are created in the coiled fiber 100. Removal of the core 510 (e.g., via dissolution, physical removal, etc.) as shown in FIG. 7b allows the coiled fiber 100 to be freed to operate unhindered in response to changes in environmental conditions (e.g., temperature, humidity, etc., as discussed herein).

[0050] The spacing between the coiled portions 240 can also be controlled through the use of spacing fibers 830, as shown in FIG. 8a. For example, as shown in example 100G of FIG. 8a, the twisted fiber 100 can be coiled around a core 510 (e.g., a mandrel or core having one or more materials as discussed herein) and wrapped with spacing fibers 830 that act as spacers for the twisted fiber 100. The spacing fibers 830 can be disposed between each of the coiled portions 240 to prevent the coiled portions 240 from contacting each other. This approach can provide a way to control the spacing between the coils in the coiled fiber 100. FIG. 8b shows the coiled fiber 100 remaining after the spacing fibers 830 and the core 510 have been removed. As discussed herein, the spacing fibers 830 and the core 510 can be removable in a variety of suitable ways, including dissolving with a solvent, physically removing, and the like.

[0051] FIG. 9a shows a first twisted fiber 1001 and a second twisted fiber 1002 coiled around a core 510 (e.g., a mandrel), with the two twisted fibers 1001, 1002 positioned side-by-side with each other. FIG. 9a shows a structure 900 including two fibers 1001, 1002 wrapped around a removable core 510, and FIG. 9b shows the structure 900 after the two nested coiled actuator fibers 1001, 1002 have been removed from the core 510. The two fibers 1001, 1002 are illustrated to show the twist, with both coils shown as homochiral coils. In the example structure 900 of FIGS. 9a and 9b, the second fiber 1002 is shown to be approximately 80% smaller in size than the first fiber 1001. In a further example, the two fibers 1001, 1002 can be the same size, or can be of suitable different sizes or diameters. In some embodiments, upon exposure to a change in environmental condition, such as a decrease in temperature, the two nested coil fibers 1001, 1002 (shown in physical contact with each other in Figures 9a and 9b) making up the structure 900 can each expand, increasing the linear length of the nested structure 900. As with the other figures, while portions of example actuators are shown, such fiber or thread material can have any length.

[0052] The sacrificial core 510 may be partially or completely removed to provide a coiled fiber actuator in a loose state on a spool or in-line during the process, although the sacrificial core may also be removed at the fabric or final product stage. As one non-limiting example, a fusible sacrificial core may be used to coil highly twisted filaments, and the sacrificial core may be removed after knitting or weaving a fabric containing the wound structure. In such cases, the sacrificial core may provide dimensional stability and ease of handling during fabric construction and processing.

[0053] The coiled fiber 100 can be produced in a variety of suitable ways. For example, a coiling machine can be used to create coils from linear fiber 100, as discussed in more detail herein. In some embodiments, such a coiling machine can include sensors that monitor the coiling of fiber 100 and modify the parameters of the coiling machine based on data obtained from such sensors. For example, in some embodiments, it can be beneficial to monitor fiber properties and use real-time information to control production. The output of the sensors can be used in a feedback loop to adjust machine parameters to result in highly twisted yarns with desired geometric and mechanical properties and minimal defects. One or more parts of the coiling machine can be individually controllable.

[0054] When twisting the fiber 100 to coiling, it may be desirable to know where along the feed path the yarn has coiled so that parameters such as yarn tension, yarn feed rate, twist insertion / m, package winding speed, or flyer rotation speed can be adjusted to prevent defects. Examples of defects can include yarn breaks, yarn snagging, or undesirable or uncontrolled snare. Some sensors can detect defects (e.g., yarn breaks) and output a signal to stop the machine or alert an engineer that a problem has occurred.

[0055] One example of a strategy for producing a coiled fiber 100 with a controllable shape is to determine the twist level along the length of the fiber 100 and adjust the spindle speed, flyer speed, and / or take-up reel speed to wind the highly twisted (and possibly coiled) yarn onto a bobbin or spool. In some examples, defects may occur if the twisted or coiled fiber 100 is not properly wound onto the bobbin. The twist level along the length of the fiber 100 can be determined by adding one or more sensors along the fiber path 100. The sensor output can be used in a feedback loop to adjust machine parameters to prevent defects and / or create a coiled fiber 100 with a desired shape. Such sensors can include optical sensors (e.g., CCD or camera systems, encoders, laser micrometers, optical micrometers, laser interferometers, etc.), mechanical sensors (e.g., spring-loaded mechanical switches, etc.), and / or electrical sensors (e.g., potentiometers, strain sensors, piezo sensors, etc.).

[0056] The shape of the twisted fiber 100 can be measured during production either directly (e.g., by measuring the diameter of the twisted fiber 100) or indirectly (e.g., by measuring other properties that correlate with the shape of the twisted fiber 100). The sensor output can be used in a feedback loop to adjust machine parameters (e.g., tension, twist rate, feed speed, take-up speed, etc.) in real time until the desired twist level and shape is achieved.

[0057] Properties that may be correlated with the twist level and shape of the working fiber 100 include, but are not limited to, filament hue / reflectance, luster, filament or fiber diameter (d), impedance, distortion, fiber smoothness or texture, local fiber velocity, etc. For example, highly twisted areas of the fiber 100 may have a significantly lower velocity than areas with lower twist levels. In some embodiments, Hall effect type sensors may be used when twisting conductive filaments or fibers 100.

[0058] In various embodiments, one or more tension sensors or feeders can be positioned along the fiber path, and data from such sensors can be used to control the shape of the twisted fiber during production. Highly twisted fiber 100 can experience axial contraction, which in some instances can increase tension in the fiber 100 unless the feed rate is adjusted to compensate for the axial contraction. Machines that impart false twist or impart true twist in the fiber 100 can be equipped with sensors that measure coil shape (directly or indirectly) and / or associated process control systems.

[0059] Sensor outputs, such as the size of the fiber 100 at a given location along the fiber path, can be fed back to the machine's process controls to inform take-up speed, tension, twist rate, feed rate, or other process variables. In some embodiments, it may be beneficial to consider the outputs of multiple sensors along the fiber path and / or outputs from one or more process measurements, such as fiber size, fiber speed, tension, and ambient conditions such as temperature and humidity. Some sensors, such as a camera, can provide more than one piece of information, for example indicating both fiber diameter (d) and fiber speed.

[0060] As a non-limiting example, the sensor can be used to monitor and control twist levels during the production of highly twisted filaments, yarns or fibers 100. Fiber bias angle α 繊維 can contribute to the performance characteristics of a fiber or yarn actuator, and the twist level in a filament, single fiber, multiple fibers, or yarns can be monitored during production to determine the twisting process and the resulting fiber bias angle α. 繊維 For example, the twist information can be used to modify the winding speed or tension on the fiber. A camera is one example of a sensor that can provide information about the twist level of the filament, which can be via determining the fiber diameter (d) (which can become thicker as it is twisted) and the fiber bias angle α. 繊維 or via another suitable method.

[0061] In another non-limiting example, sensors can be used to monitor the coiling of the environmentally responsive actuator fiber 100, which can provide information useful in controlling the production of the coiled fiber 100. For example, a camera or other suitable vision system can provide information regarding the twist level of the fiber 100, which can be used to monitor the twist level of the fiber 100 prior to coiling, which can be used to monitor the rate of coiling or the location of coiling along the fiber 100, and such information can be used in determining an appropriate take-up speed and / or in adjusting tension for the coiled fiber 100. In some embodiments, such a system can determine the coil diameter (D), which in some examples can be important in the final properties of the fiber 100, and the coil diameter information can be provided to a machine control system to increase or decrease tension, which can directly affect the coil diameter (D) when producing the coiled fiber 100.

[0062] Various information obtained from sensors that directly monitor the process or monitor the ambient conditions can be incorporated into the coiling machine control system. As non-limiting examples, in-line process measurements of coil diameter (D), along with ambient humidity, temperature measurements, etc., can be used to inform control of the tension and / or winding speed of the fiber 100 being processed.

[0063] For example, Figure 10 is a schematic diagram of a manufacturing method 1000 that, in some embodiments, is monitored and controlled by sensors to partially or fully automate the process, eliminating the need for user interaction during any or all of the method 1000. At 1010, the fiber or yarn from a source is tensioned and fed to a location where the material is twisted at 1020. The twisted and possibly coiled fiber or yarn can then be wound onto a bobbin or spool at 1030. The three stages 1010, 1020, 1030 are shown as boxes with solid lines, and the movement of the material from tensioning to twisting to winding is shown by solid arrows. Process sensors 1040 and ambient sensors 1050 are represented by boxes with dashed edges, and dashed arrows shown between the various boxes indicate feedback for the control of stages 1010, 1020, 1030.

[0064] As an example of how sensors (e.g., sensors 1040, 1050) can affect process conditions and control, environmental sensors monitoring temperature and humidity can inform fiber tension set points and allow the feeder to insert more material into the twist zone if tension becomes too high. In other words, in some examples, data obtained from one or both of sensors 1040, 1050 can be used to determine and implement fiber tension settings and / or feed rates, which can include increasing or decreasing tension and / or increasing or decreasing feed rates. Such feed rates can include feeding from a fiber source and / or feeding into the twist zone. For example, temperature and / or relative humidity data obtained from ambient sensor 1050 can inform the twist rate, as under some environmental conditions it may be desirable to increase or decrease the twist rate.

[0065] In some embodiments, a sensor 1040 (e.g., a camera) monitoring the process can provide information for controlling both tension 1010 and winding speed 1030. As a non-limiting example, the process sensor(s) 1040 can include a vision system, such as a camera, that can be used to monitor the formation of coils in the fiber during the process of further twisting the highly twisted fiber to induce coiling. Prior to coiling, the thickness of the fiber or yarn can be a particular thickness that the vision system can know and measure through pixel counting or other suitable process as part of the image analysis. While twist insertion can also change the thickness of the fiber, coiling can significantly change the effective thickness of the fiber, increasing the pixel count across the width of the material.

[0066] In the twisting process, once the coil has started to form, it can be grown by inserting additional twist to expand the coil throughout the twisted fiber or yarn. Within the field of view of the vision system, image analysis can be used to determine the presence of the coil, and by comparing frames in the video, the coil's speed of advance and retreat can be determined. At 1030, when the coiled fiber or yarn is wound onto a spool or bobbin, if the winding speed is too fast, the coil will move out of the field of view of the process sensor 1040 (e.g., out of the field of view of the vision system). Alternatively, if the winding speed is too slow, the coil expansion will likely progress throughout the field of view of the process sensor 1040, and the coil structure may move backwards in the system towards the tension feeder. The coil expansion moving backwards towards the tension feeder and the coil expansion moving forward towards the winding bobbin may be undesirable. Thus, the process control can use information from the process sensor 1040 (e.g., image or video analysis of data obtained from a camera or other vision system) to keep the process stable. In other words, data obtained from the process sensors 1040 can be used to control variables such as tension, feed rate, twist rate, winding speed, etc. to maintain the coil formation origin at a desired location or within a desired range of locations.

[0067] For example, Figure 11a shows an example of a fiber coiling system 1100 that includes a fiber source spool 1102 that supplies fiber 100 to a take-up spool 1104 that receives and takes up the fiber 100. It should be noted that the configuration of fiber coiling system 1100 in Figure 11a is merely an example of one configuration of such a fiber coiling system 1100, and that any other suitable fiber source, fiber take-up elements, and tensioning elements are within the scope and spirit of the present disclosure.

[0068] As further shown in Figure 11a, the fiber 100 can include a straight portion 1110 exiting a source spool 1102 and a coiled portion 1120 that is wound onto a take-up spool 1104. A coiling origination region 1130 separates the straight portion 1110 and the coiled portion 1120 and is the location where the straight portion 1110 of the fiber 100 becomes the coiled portion 1120 as the fiber travels from the source spool 1102 to the take-up spool 1104. In addition, Figure 11a shows a coiling origination window 1140 that can be monitored by one or more process sensors 1040, such as a camera 1150, as shown in the example system 1100 of Figure 11a.

[0069] The coil formation origin window 1140 can include a desired location where the coil formation origin region 1130 should be located. As the fiber 100 moves between the source spool 1102 and the take-up spool 1104 and coils at the coil formation origin region 1130 on the fiber 100, the coil formation origin region 1130 can move toward the take-up spool 1104 (e.g., as shown in FIG. 11b) and can move toward the source spool 1102 (e.g., as shown in FIG. 11c), potentially moving the coil formation origin region 1130 out of the coil formation origin window 1140 (e.g., as shown in FIGS. 11b and 11c). Thus, the system 1100 can monitor the position and movement of the coil formation origin region 1130 via one or more process sensors 1040 and adjust the operating configuration of the system 1100 in real time to maintain the coil formation origin region 1130 within the coil formation origin window 1140 and / or move the coil formation origin region back within the coil formation origin window 1140.

[0070] As an example, if the expanding coil portion 1120 moves towards the take-up bobbin or take-up spool 1104, the take-up speed on the take-up spool 1104 can be slowed down and the coil formation origin region 1130 can be moved towards the source spool 1102. As another example, if the expanding coil portion 1120 moves towards the fiber feeder spool 1102, the take-up speed on the take-up spool 1104 can be increased. By monitoring not only the location of the coil formation origin region 1130 but also the speed of the coil formation origin region 1130, the take-up speed on the take-up spool 1104 can be made adjustable according to the rate of expansion of the coil formation origin region 1130. However, in further embodiments, sufficient process stability can be obtained through only identifying the location of the expanding coil formation origin region 1130. In some embodiments, the take-up speed on the take-up spool 1104 can be held constant, and changes in the location and / or speed of the expansion (growth) of the coiled origin region 1130 during the manufacturing process can be fed back to control the twist rate of the fiber 100, which can increase the twist into the coil more quickly, thereby moving the expansion (growth) of the coiled origin region 1130 away from the take-up spool 1104 and towards the fiber source spool 1102. In further embodiments, slowing the twist rate of the fiber 100 can slow the coiling rate and move the expansion (growth) of the coiled origin region 1130 away from the fiber source spool 1102 and towards the take-up spool 1104.

[0071] As another example, a process sensor 1040 in a manufacturing method 1000 as shown in FIG. 10 can provide information to a control system to affect the shape of the coiled fiber 100 produced by the system 1100. As an example, image or video analysis of data from a camera 1150 or the like can be used to determine the coil spring index (C) of the coiled material by referencing the fiber diameter (d) relative to the coil diameter (D) (see FIGS. 1 and 2). Both the fiber diameter (d) and the coil diameter (D) can be measured in a variety of suitable ways (e.g., through pixel counting across images or frames of the material during processing). In some embodiments, the coil spring index (C) can be a relative measurement rather than an absolute measurement, so referencing pixel counting can be a simple way to determine the coil spring index (C) to partially understand the shape of the as-formed coil portion 1120. Thus, in some examples, calibration may not be necessary. In various embodiments, if the monitored or determined coil spring index (C) is found to be too low or below a predetermined minimum coil spring index threshold, the tension in the fiber 100 can be decreased. Alternatively, if the monitored or determined coil spring index (C) is found to be too high or above a predetermined maximum coil spring index threshold, the tension in the fiber 100 can be increased.

[0072] In some embodiments, it may be desirable to increase the speed at which twisted coil actuators are manufactured. However, in some examples, a faster twisting rate may increase the likelihood that the fiber will form undesirable kinks or typical snarls (see FIG. 12a) rather than twisting into a cylindrical coil (see FIG. 12b). In some examples, a higher tension on the fiber 100 may reduce the likelihood of entanglement (typical snarls) due to the tighter twist. However, a higher tension may also produce a tighter coil of the fiber 100, resulting in a lower spring index (C).

[0073] An example of an alternative approach may be to limit the physical space for the twisting fiber 100 so that the fiber 100 does not have the physical space required for the distortion associated with the formation of a kink or a typical snarl (see FIG. 12a). In some embodiments, both a typical snarl and a tubular twist require the fiber 100 to physically distort, but in some instances, a kink or a typical snarl may be positioned perpendicular to the fiber draw direction and require more space. In some instances, limiting the space that can be provided to the entangled fiber or yarn, such as through the use of a restraining tube, may allow for the removal of the space required for the formation of a kink or a typical snarl while at the same time retaining sufficient physical space to allow a tubular twist to form.

[0074] For example, in some embodiments, the coiling machine 100 can include a constraining tube through which the fiber 100 passes, the inner diameter of the constraining tube being equal to or greater than the desired coil diameter (D) or maximum coil diameter, and equal to or less than the diameter or width of a kink or typical snare that may be generated by the fiber 100 in the absence of the constraining tube.

[0075] As discussed herein, the coil shape and / or coil spacing can affect the properties of the twisted and coiled actuator for various embodiment actuators. However, control of the coil shape and / or coil spacing can be performed in a variety of suitable ways. For example, one approach can be to control the manufacturing temperature and / or moisture level during manufacturing. In some instances, it may be beneficial to use different temperatures (or moisture levels) during the twisting and untwisting steps, just as in some instances it may be beneficial to use different tensile loads during twisting and untwisting. Alternatively, it may be beneficial to vary the tension depending on the temperature.

[0076] In various embodiments, one or more coiled fibers 100 as discussed herein can be formed into a coiled fiber actuator that can respond to environmental conditions such as temperature, humidity, moisture, etc. To practically use such coiled fiber actuators, in some embodiments, it may be desirable to control the range or limits of the thermal response (e.g., stroke, Δlength / Δtemperature) and / or temperature response. For a given fiber material, the coil bias angle α of the coil can be adjusted to 0.5° C. to 10° C. コイル The shape or structure of the coil, including and coil diameter (D) or openness, can affect the degree of thermal responsiveness (e.g., a larger coil diameter (D) can have a larger coil spring index (C) and such a coil can be more thermally responsive). In addition, one end of the temperature response range can be controlled through the spacing of the coils (e.g., if the coil portions 240 are abutted against each other, contraction of the coiled actuator will require compression of the material and the degree of thermal responsiveness may be greatly reduced).

[0077] For practical use of a coiled actuator, in some instances it may be desirable to have a desired thermal response (e.g., the amount of actuation for a given temperature change, i.e., Δstrain / ΔT) of the coiled actuator, and it may be desirable for the coiled actuator to respond over the temperature range that is relevant for the application. In some cases it may be beneficial to control the operating range, as well as the minimum useful length (e.g., at a particular temperature) and the maximum length (e.g., at another temperature), so that it will only operate effectively between these two temperatures and between these two lengths.

[0078] In some embodiments of thermal actuators with a negative coefficient of thermal expansion (actuators in which the fiber twist and the coil twist are in the same direction (e.g., homochiral coils)), above a certain temperature, the coils may contact each other (coil contact temperature) and reach the actuator's minimum effective length. In various examples, a homochiral coiled fiber actuator will have physical space between its coils when its temperature is below its coil contact temperature. Artificial muscles can be used in robotics applications, where they can move a mass. In these applications, a load can be first attached to the coiled actuator, allowing the coils of the actuator to stretch and pull apart, lifting the load when the actuator contracts. However, applications in which the actuator is not pre-stretched or pre-attached to the actuator may require the coiled fiber to actuate within the temperature range of interest, in some embodiments. For garments and other applications where actuation near body temperature may be desired, the actuator may in some instances not reach a compressed state (where the coil is in contact with an adjacent coil) until temperatures outside the desired operating range, and may be operable throughout the range. However, some existing methods for making coiled actuators produce actuators that require low temperatures (e.g., less than 10° C.) to stretch when the actuator is unloaded, as may be the case in some apparel examples. Control over the physical spacing between the coils and the coil contact temperature where adjacent coils contact, as well as high responsiveness to temperature drops, may be important to make coiled textile actuators practical for actuating textiles, particularly for apparel and bedding.

[0079] In various embodiments, control of the spacing 260 between the coil portions 240 can be used to control the coil contact temperature, above which some coil actuators can be effectively shut down. To increase the spacing 260 between the coil portions 240, excess residual twist and residual compressive stress in the as-fabricated coil can be reduced or eliminated through untwisting, as described above. The coiled fiber actuator can be heat set (e.g., annealed), and the set conditions can also contribute to the spacing between the coils. The coil can be temperature responsive by design and can respond to large temperatures during heat setting, which can exceed 200° C. in some instances, depending on the material. In some instances, depending on the particular annealing conditions (e.g., time, temperature, the presence of any co-agents such as water, etc.), a significant amount of residual compressive stress in the material can be eliminated. In various embodiments, any portion that remains or is fabricated through heat setting can affect the coil spacing.

[0080] Heat setting can be performed at various suitable temperatures and various suitable times. For example, in some embodiments, heat setting can be performed at 140°C, 170°C, or 200°C. In further examples, heat setting can be performed at temperatures of 150°C or less, 140°C or less, or 130°C or less, etc. In further examples, heat treatment can be performed at temperatures above 100°C, above 110°C, above 120°C, above 130°C, or above 140°C. The temperature range of such heat treatment can be within a range between any of these example temperatures. In some examples, the coiled actuator can be heat treated within the desired temperature range for various suitable periods of time, including 15 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, or 4 hours. Additionally, heat treatment can be performed within a suitable range bounded by any of these example periods.

[0081] For the same heat-setting conditions, three non-limiting example cases are described herein. The first example is where the textile actuator is free to move during the setting procedure. The high temperature of the process can cause the coil to compress, and the actuator can then be set in that compressed position. Once the heat-setting procedure is over, the coil may tend to expand as the temperature drops, but in some instances some residual compressive forces may work against the coil expansion, and the coils may remain in contact with each other at room temperature or the relevant temperature range of the intended application.

[0082] In a second example heat-setting procedure, the fiber actuator is physically constrained during the annealing process to prevent the temperature rise from physically drawing the coils closer together. There are many ways to accomplish this, for example, one embodiment includes constraining the entire fiber lot during the setting procedure, such as by winding the fiber actuator on a spool and wrapping the spool with a sheet or tape that can withstand the conditions of the setting procedure. In some embodiments, after the setting process, the cooled actuator coils may tend to expand and move apart more than would be the case for a heat-set actuator that is free to contact during the setting process. The coil contact temperature of a fiber actuator that is constrained during the heat-setting process may be higher than for a similar actuator that is heat-set without physical constraints, and this higher coil contact temperature may allow the actuator to be used unloaded at room temperature and body temperature, or other desired temperatures. As discussed herein, body temperature can include temperatures including about 37.0° C., 38.0° C., 39.0° C., etc., and temperatures typically found on the skin or in the environment surrounding the skin, including about 27.0° C., 28.0° C., 29.0° C., 30.0° C., 31.0° C., 32.0° C., 33.0° C., 34.0° C., 35.0° C., 36.0° C., etc. As discussed herein, room temperature can include temperatures including about 10.0° C., 15.0° C., 20.0° C., 25.0° C., 30° C., etc.

[0083] The heat setting procedure in the third example is similar to the second example in that the fiber actuator is constrained during the heat setting process, but in the third example, the actuator is constrained by intentionally stretching it during the process. In some embodiments, this allows the coil contact temperature to move to even higher values. In each of these three cases, temperature, time, and the presence of any chemical agents that aid in the setting of the material may be additional factors.

[0084] In some embodiments, in environmentally responsive twisted and coiled fiber and yarn actuators, if the set procedure is modified to move the coil contact temperature to a higher value, the coil (coil bias angle α コイル At lower temperatures (as reflected by an increase in |CTE| ≥ 2 mm / m / K) the actuator may become more stretched and its thermal response may decrease. In some example applications in garments and textiles, it may be desirable to have both a high thermal response (e.g., |CTE| ≥ 2 mm / m / K) and a high coil contact temperature (e.g., 20°C, and in some cases more preferably 40°C).

[0085] In some embodiments, in coiling through winding, untwisting can be used to increase the coil diameter (D) and can affect the coil spacing 260. Additionally, the spacing 260 between the coil sections 240 in some embodiments can be controlled by winding the working twisted fiber 100 around the mandrel or other core material 510 with some spacing 260 between the coil sections 240 (see FIG. 7a) and / or by winding the working fiber 100 with a sacrificial fiber 830 around the mandrel or other core material 510, with the sacrificial fiber 830 acting as a physical spacer between the coil sections 240 (see FIG. 8a). The sacrificial material 830 can be physically removed (e.g., uncoiled), dissolved, removed by chemical means, etc. The diameter or size of the sacrificial material can correspond to the diameter or size of the twisted fiber 100 being coiled, or the sacrificial material 830 can be larger or smaller than that as a way of controlling the spacing 260 between the coils in the final actuator fiber 100.

[0086] In some embodiments, the coil contact temperature can be used to limit the actuator's range of motion. In some applications, it may be beneficial to limit the minimum length of the actuator, and by controlling the coil contact temperature, that minimum length can be set for that temperature or any higher temperature. In some instances, some change may be seen as the temperature continues to increase, but since the coil is not free to move, the change may be fairly small (this description assumes that the coiled actuator expands as the temperature decreases, as is the case with homochiral coils, but a heterochiral coil, where the coil direction is opposite to the twist direction, may have the opposite behavior, compressing to a minimum size as the temperature decreases and the coils come into contact, and when a coil portion 240 comes into direct contact with an adjacent coil portion 240 (see, for example, FIG. 3b), the coil portion 240 may have substantially less thermal contraction at temperatures below the coil contact temperature).

[0087] Control of the coil contact temperature can provide some control over the stiffness (e.g., effective modulus) of the actuator. In various embodiments, when the coil portions 240 come together, the stiffness of the actuator can be increased, which can be exploited in designs incorporating fiber actuators.

[0088] In some examples, the extension of the actuator can be controlled by wrapping the fiber around it so that the actuator becomes a protected, environmentally responsive core within the yarn. As the actuating core lengthens, the outer fiber (e.g., continuous filament, staple fiber, etc.) can be pulled in a direction of increasing straightness to a point where the outer fiber straightens sufficiently to exercise its resistance to tensile extension. At this point, in various examples, the actuator can enter a thermal response region (where further extension may be significantly hindered by the wrapping fiber) and the maximum length of the actuator is effectively achieved. In some embodiments, wrapping or covering the coiled actuator can provide many other benefits, including feel, appearance, protection from snags, controlled wicking, moisture handling, chemical resistance, improved overall volume of the actuating yarn, etc. Wrapping can also be used to counteract the torque of the fiber actuator. For example, both ends of the actuator can be constrained to convert the twisting action of the coil into a linear dimension change in response to temperature changes. This constraint requirement can be eliminated if the actuator is wrapped or layered with fibers of the opposite twist direction (e.g., a Z-twist actuator can be wrapped with S-direction fibers or layered with S-direction fibers).

[0089] Although the various examples disclosed herein relate to thermal responsiveness of the coiled actuators, these materials may have moisture and / or chemical sensitivity in addition to or instead of thermal responsiveness, and references to responsiveness or adaptability to temperature or environment are intended to include moisture, water and / or chemical sensitivity.

[0090] Various embodiments described herein may include monofilament or multifilament yarns. However, in further examples, staple yarns may be used to create coiled thermal actuators. In some embodiments, individual fibers in such yarns may be crosslinked through surface interactions, or the yarn in its drawn form with coils apart may be impregnated with crosslinking or polymerization agents to improve the long-term health of the thermally responsive yarn. In some examples, the yarn itself may act as a vehicle for distributing liquid polymerization agents through wicking. Similarly, a material may be used as a coating over the staple or multifilament yarns to act as a filler or brightener. Such materials may include sizing agents applied as a solution or may include polymers applied through a melt process. In some embodiments, the protective material may be removed after the fiber or yarn actuator is twisted and coiled, where the protective material serves as a sacrificial material to aid in the fabrication of the actuator.

[0091] Desired shape (e.g., high spring index C, small coil bias angle α コイル An example approach to making a coil having a twisted portion 260 between coil portions 240 (e.g., controlled spacing 260 between coil portions 240) can include braiding one or more pre-twisted (but in some instances uncoiled) fibers 100 with one or more sacrificial fibers. Braiding can be done with or without a core 510. The braided yarn can be heat set and the sacrificial fibers and core can be removed through physical means, dissolving, melting, washing, chemical methods, etc.

[0092] Desired shape (e.g., high spring index C, small coil bias angle α コイルAnother example approach to making a coil having a twisted core (e.g., controlled spacing 260 between coil portions 240) can include wrapping or winding one or more pre-twisted (but in some examples, uncoiled) fibers 100 around one or more sacrificial fibers or yarns. The one or more sacrificial fibers can define the shape of the central cavity 220 of the coil formed around the one or more sacrificial fibers. The wrapped or wrapped fiber or yarn can be heat set and the sacrificial fiber or fibers can be removed through physical means, dissolving, melting, washing, chemical methods, etc., to release the wrapped fiber coil from the core. In this example approach to making an actuator, the sacrificial core can act as a template or structure around which the fiber can be wound. The fiber or yarn used to wind the core can be a monofilament or continuous filament yarn, or it can be a staple yarn that is optionally prepared with a removable sizing and / or lubricant to facilitate the formation of the coiled structure.

[0093] In some instances, when including fine yarns that may have a high spring index, the effective modulus may be too low to achieve the desired thermal or mechanical performance. To increase the effective modulus, the coils may be wound on an elastic or inelastic core during manufacturing, which may remain part of the yarn in the final product. The coils may in some instances be wound on a multicomponent core, in which case a portion of the core may be removed by dissolution, chemical means, physical means, etc. after winding / heat setting.

[0094] Crossed yarn wrapping can also involve wrapping one or more fibers 100 around a sacrificial core 510, where a first set of one or more fibers 100 are wrapped around the core 510 in one direction (S or Z) followed by an additional wrapping operation in which a second set of one or more fibers 100 are wrapped around the core 510 and the first wrap (which can include one or more fibers 100 of the first set) in the opposite direction (Z or S). In some embodiments, both the first set of fibers 100 and the second set of fibers 100 can be highly twisted to result in nested coil actuators in which a Z-twisted outer homochiral coil surrounds an S-twisted inner homochiral coil, or an S-twisted outer homochiral coil surrounds a Z-twisted inner homochiral coil, creating a balanced or partially balanced actuating yarn. In some embodiments, only the first set of fibers or the second set of fibers are highly twisted, and the other set of fibers may be present for support, restraint, protection, bulk, or other suitable purpose.

[0095] For smaller diameter fibers or yarns (e.g., less than 0.25 mm), commercially available winding or wrapping equipment can provide the appropriate level of twist or coiling per linear length to achieve the coil bias angle α. コイルIt may not be possible to create a compact coiled actuator with minimal stiffness. In one non-limiting example, a winding machine capable of coiling less than 5000 coils per meter can wrap a highly twisted 100 micrometer filament around a central sacrificial fiber or yarn, leaving more than 100 micrometers of space between each coil. Such spacing can be left in the coiled material, but instead, a highly twisted second filament (or a second and a third, or a second, third and fourth, etc.) can be wound simultaneously around the central core to form two coils, each nested inside the other. In some examples, the environmental responsiveness is unchanged by the presence of the nested coil, but a nested coil or multiple nested coils may have some differences in properties. For example, the presence of a second coil may reduce the range of contraction. In another example, the overall stiffness of the nested coils may be higher than the stiffness of the individual coils. In terms of manufacturing, the addition of a second filament, in various examples, does not necessarily add processing time to the coiling step and may improve reliability since the two (or more) filaments can stabilize each other and effectively constrain each other during the manufacturing process.

[0096] In some embodiments, the application of heat may not be necessary to set the coil into the desired shape. For example, mechanical setting through plastic deformation may be used. In some instances, chemical methods may be used to remove residual mechanical stresses and set the coil into the desired shape.

[0097] Fibers with special cross sections, including hollow-center precursor fibers, can be used to increase the insulating value and reduce the weight of some actuators made from the fibers. In various embodiments, non-circular cross sections can increase the surface area of ​​the fiber 100 to enhance wicking, dryness, feel, etc.

[0098] Coiled actuators or artificial muscles including one or more of the coiled fibers 100 discussed herein can have a variety of suitable applications in apparel, bedding, curtains, thermal insulation, and the like. For example, in some embodiments, apparel such as a coat, sweater, and the like can include an adaptive textile including a plurality of coiled actuators including a plurality of coiled fibers 100, the adaptive textile including a first layer of the adaptive textile configured to surround and face the body of a wearer and a second layer configured to face the wearer's external environment. Such configurations can include linear and / or exterior surfaces upon which the adaptive textile can be positioned. In another embodiment, only one adaptive layer may be used in a garment or other product.

[0099] In various embodiments, apparel including adaptive fabrics can be configured to change configuration based on the wearer's body temperature and / or the temperature of the external environment, which can include increasing or flattening to provide more or less insulation based on temperature. For example, when the environmental temperature is lower than a desired comfort temperature for the user's immediate environment (e.g., around 27°C), the outer and / or inner layers of the adaptive fabric can be configured to increase in volume to provide better insulation from cold air for the user, with the lower the temperature the greater the degree of increase in volume and insulation. Alternatively, when the environmental temperature is higher than a comfortable temperature for the user, the outer and / or inner layers of the adaptive fabric can be configured to flatten to provide less insulation for the user.

[0100] Additionally, the adaptive fabric of the apparel can be configured to change configuration based on moisture associated with a wearer's body to direct such moisture away from the wearer's body. For example, if a user sweats and generates moisture while wearing apparel including the adaptive fabric, the adaptive fabric can be configured to increase its porosity and / or flatten to direct such moisture from within the apparel, in a direction outside the apparel and away from the user.

[0101] Adaptive fabrics or adaptive woven fabrics including multiple coiled actuators can be made in a variety of suitable ways and can have a variety of suitable characteristics. For example, the difference in coefficient of thermal expansion (ΔCTE) between two materials is a term that can indicate the range of motion or deflection of a structure such as a bimorph or other structure having multiple coiled actuators. In some example materials, the ΔCTE term can be 100-200 μm / m / K, which may not be desirable for some embodiments. Thus, various embodiments of bimorphs can include highly twisted coil actuators as described herein (e.g., Figures 15a, 15b, 16a, 16b, 17a, 17b, and 18), which in some embodiments can have effective CTE values ​​of 1000 μm / m / K or more, resulting in comparable ΔCTE values. In some examples, such CTE values ​​can be useful in bimorphs and bilayer structures with desired deflection or bending characteristics.

[0102] In various embodiments, the coiled actuator can function as a thermally responsive tensile actuator (linear motion) and / or torsional actuator (rotary motion). In further embodiments, the structures described herein can convert the linear motion of the coiled actuator into orthogonal motion through the use of complementary materials. Such embodiments may be desirable for use in thermally responsive yarns, wefts, felts, fabrics, and the like that can be used to construct garments and other articles that thicken when exposed to low temperatures.

[0103] In various embodiments, it may be desirable to pair materials to provide a large difference between the CTE values ​​(ΔCTE) of the two paired materials. Thus, a coiled actuator 1210 with a large CTE may be desirable for use in bimorphs and bimorph-containing structures. In some embodiments, the coiled actuator may have a positive CTE (e.g., expansion with increasing temperature, heterochiral coils with opposite twist and coil directions) or a large negative CTE (e.g., contraction with increasing temperature, homochiral coils with the same twist and coil directions). In various embodiments, and as described herein, pairing oppositely coiled actuators with the same filament material can provide a large ΔCTE.

[0104] In various embodiments, the bimorph can include a twisted coil actuator where linear displacement of the actuator due to temperature change can induce out-of-plane or orthogonal deflection in the bimorph, resulting in an effective change in height or thickness of the bimorph.

[0105] 15a and 15b show an example 1500A of a bimorph 1500 comprising a coiled actuator fiber 100 and a filament 1520 connected at a first end 1530 and a second end 1540. The coiled actuator fiber 100 and the filament 1520 can be connected only at the first end 1530 and the second end 1540 and / or can be connected along a portion of their length.

[0106] In various embodiments, the coiled actuator fiber 100 can expand or contract lengthwise in response to a change in temperature. For example, the coiled actuator fiber 100 can contract when cooled (heterochiral fiber actuator, where the twist direction and coil direction are opposite) or expand when cooled (homochiral fiber actuator, where the twist direction and coil direction are the same). In various embodiments, the filament 1520 can expand, contract, or show no substantial change lengthwise.

[0107] Figure 15a shows a bimorph 1500A (left) in a flat configuration at a first temperature and bimorph 1500A (right) in a first contracted configuration due to a temperature change. Figure 15b shows the bimorph 1500A (left) of Figure 15a in a flat configuration at a first temperature and bimorph 1500A (right) in a second contracted configuration due to a temperature change opposite to that shown in Figure 15a. For example, Figure 15a may show a configuration change due to a negative temperature change and Figure 15b may show a configuration change due to a positive temperature change.

[0108] In various embodiments, the coiled actuator fiber 100 and filament 1520 can both be configured to bend as shown in the example embodiments of Figures 15a and 15b, where lengths of the coiled actuator fiber 100 and filament 1520 are adjacent in both the bent and straight configurations. In further embodiments, the coiled actuator fiber 100 and filament 1520 can be configured to bend in different ways, where the coiled actuator fiber 100 and filament 1520 can be non-adjacent in the flat and / or bent configurations.

[0109] 16a shows an example embodiment 1500B of a bimorph 1500 having a coiled actuator fiber 100 and a filament 1620, where the coiled actuator fiber 100 maintains a straight configuration whether the bimorph 1500 is in a flat configuration (left) or a bent configuration (right). In this example, the coiled actuator fiber 100 is shown to contract due to a change in temperature, causing the filament 1620 to bend away from the coiled actuator fiber 100.

[0110] Similarly, Figure 16b shows another example 1500C of a bimorph 1500 comprising a first filament 1620A and a second filament 1620B, along with a coiled actuator fiber 100 between the first filament 1620A and the second filament 1620B. In this example, the bimorph 1500C is shown to contract due to a change in temperature, causing the filaments 1620A, 1620B to bend away from the coiled actuator fiber 100, which maintains a straight configuration.

[0111] 17a and 17b show two examples 1500D, 1500E of a bimorph 1500 comprising a first coiled actuator fiber 100A1 and a second coiled actuator fiber 110B1 connected at a first end 1530 and a second end 1540. In some embodiments, the coiled actuator fibers 100A1, 110B1 can be connected along a portion of their length. FIG. 17a shows an example embodiment 1500D in which the coiled actuator fibers 100A1, 110B1 have opposite thermal responses and remain adjacent in both flat (left) and bent (right) configurations. In contrast, FIG. 17b shows an example embodiment 1500E in which the coiled actuator fibers 100A1, 110B1 are adjacent in the flat (left) configuration and can separate in the bent (right) configuration.

[0112] 18 shows an example embodiment of a bimorph 1500F having a coiled actuator fiber 100 and a filament 1520 that maintains a straight configuration when the bimorph 1500 is in a flat configuration (left) and a bent configuration (right). In this example 1500F, the coiled actuator fiber 100 is shown to expand due to a change in temperature, which causes the coiled actuator fiber 100 to bend away from the filament 1520.

[0113] In various embodiments, one or more twisted coil actuator fibers 100 are connected to one or more rigid opposing filaments 1520 that can act as immobile structures (relative to which the actuator fiber 100 can be displaced in orthogonal directions) resulting in a structure that experiences minimal linear expansion as its effective thickness changes. Figure 18 shows an example of such a structure.

[0114] In addition to the desired effective CTE value, the coiled actuator fiber 100 may provide several processing or fabrication advantages, such as mechanical connection paths not available in sheet structures, as well as the ability to create both positive and negative CTE coils from the same length of material, as discussed herein. A large spring constant for the coiled actuator fiber 100 may maximize the effective CTE value of the coiled actuator fiber 100 while leaving an open cavity 220 in the center of the coil. Coiled actuator fibers 100 may be desirable due to the porosity, density, and breathability that may be present in such structures.

[0115] In various embodiments, one or more coiled actuator fibers 100 and / or bimorphs 1500 can be woven or sewn into a fabric or thin film to create a bimorph sheet structure with a large effective ΔCTE value and correspondingly large deflection. In further embodiments, one or more coiled actuator fibers 100 can be sewn or bonded to a sheet to create a bimorph sheet. In some embodiments, one or more coiled actuators having alternating coil sections with alternating expansion and contraction sections of opposite chirality can be sewn or bonded to the surface of a sheet or fabric. When the temperature is changed, the positive and negative thermally responsive areas in the alternating chirality coiled actuator fiber 100 can form a sheet structure in which the sheet or ribbon assumes a sinusoidal shape. The alternating chirality coiled actuator embodiments can have applications in a variety of fields. For example, various embodiments can be configured for the production of thermally adaptive garments, where alternating chirality coils can be used in a traditional lockstitch to create alternating regions of positive and negative CTE on the surface of the fabric to induce undulation in the fabric as the temperature changes. In some embodiments, the second yarn or fiber in the lockstitch need not be a high CTE coil actuator material or a twisted coil actuator material.

[0116] In some embodiments, multiple coiled actuator fibers 100 can be arranged in parallel and woven or stitched together to create a sheet or layer with a desired CTE in a single direction. In further embodiments, such sheets with different CTEs (e.g., a sheet with a largely positive CTE and a sheet with a largely negative CTE) can be paired to create a flat bimorph sheet with a desired differential thermal expansion and a desired radius of curvature.

[0117] In further embodiments, the coiled actuator fiber 100 can be sewn onto a thin film, membrane, or fabric, thereby imparting thermally responsive properties to such thin film, membrane, or fabric. Thus, various embodiments can eliminate the need to incorporate an insulating material or fabric more deeply into the selected material. In such embodiments, the thermally responsive material can also be part of the fabric, be a major part of the insulating material, be the substrate, or be secured to another material via an adhesive or thermal bond.

[0118] Additionally, the coiled actuator fiber 100 can be used to create branched structures similar to that of goose down. For example, in some embodiments, the twisted fiber 100 can be pulled through a layer of fine fibers during the coiling process, trapping or capturing the fine fibers within the coil to create a branched structure with good insulating, feel, and structural properties in the context of greater variable insulating properties.

[0119] The coiled actuator fiber 100 can function as a linear or torsional actuator. In various embodiments, pairing two different materials can produce out-of-plane or orthogonal motion as discussed herein. In some embodiments, a woven or knitted structure that pairs twisted coils with different CTE properties in an antagonistic manner can include a thermally responsive bimorph 1500. In some embodiments, multiple materials can be woven together in various suitable ways to create an overall physical structure of the textile that changes in response to temperature. Such a woven structure can include coiled actuator fiber 100 or other suitable materials or structures that change configuration or length in response to temperature.

[0120] In various embodiments, a woven or knitted structure can act as a constraint by aligning the fibers so that their overall motion is cohesive and not characterized by random individual twisting of disparate fiber groups, which may be desirable for thermally adaptive materials and maximizing their deflection or changes in their effective thickness.

[0121] In further embodiments, the temperature-sensitive structure may include non-compliant constraints, such as fibers, threads, or fabrics, against which the actuating material acts, such that the non-compliant material remains linear, straight, or flat and the actuating material expands and becomes bulky, or the actuating material remains linear, straight, or flat and the non-compliant material becomes bulky as the actuating material contracts. Appropriate constraints, such as through weaving or knitting, or the use of adhesives, can provide the desired temperature responsiveness in such structures. In some embodiments, it may be beneficial to use constraints that limit the range of motion of the material.

[0122] In further embodiments, the coiled actuator fiber 100 or artificial muscle comprising one or more coiled fibers 100 may be used as a mechanical actuator for: (i) a woven fabric or braiding yarn; (ii) a mechanical mechanism for opening and closing shutters or blinds to regulate light transmission or airflow; (iii) a mechanical actuator for a medical device or toy; (iv) a pump, valve actuator, or fluid mixer, large or small; (v) a mechanical relay for opening and closing electronic circuits or opening and closing locks; (vi) a torsional actuator for a rotating electrode for sensitive electrochemical analyte analysis; (vii) a mechanical actuator for an optical device; (viii) a mechanical actuator for an optical device for opening and closing light shutters, translating or rotating lenses or light diffusers, producing deformations that change the focal length of standard lenses, or rotating or translating pixels on a display to achieve a changing image on the display; (ix) a mechanical actuator for providing tactile information; (x) a mechanical actuator for providing tactile information for a tactile device in a surgeon's glove or a braille display; (xi) a smart actuator for enabling changes in surface structure. (xii) mechanical drive systems for surfaces; (xiii) mechanical drive systems for providing realistic facial expressions to humanoid robots; (xiv) smart packaging for temperature sensitive materials that open and close vents or change porosity in response to ambient temperature; (xv) mechanical systems that open and close valves in response to ambient temperature or temperature due to photothermal heating; (xvi) mechanical drives that control the orientation of solar cells with respect to the direction of the sun using photothermal or electrical heating; (xvii) photothermally actuated microdevices; (xviii) thermally or photothermally actuated energy harvesters that use temperature fluctuations to generate mechanical energy that is harvested as electrical energy; (xix) tight-fitting garments that use thermal actuation to facilitate insertion into the garment; (xx) devices for providing adjustable compliance, where the device provides adjustable compliance by electrothermal actuation; (xxi) translational or rotational positioners, and the like.

[0123] The described embodiments are susceptible to various modifications and alternative forms, specific examples of which have been shown by way of example and are described in more detail herein. It is to be understood, however, that the described embodiments are not limited to the particular forms or methods disclosed, but rather, the disclosure is intended to cover all modifications, equivalents, and alternatives. EXAMPLES

[0124] First and second embodiments Figures 13 and 14 show two environmentally responsive coiled fiber actuators fabricated according to the methods described herein. The microscopy images in Figures 13 and 14 show coils with geometries fabricated by the two different methods. The scale bar is 0.5 mm in length.

[0125] In Figure 13, highly twisted fiber coils were fabricated from 0.1 mm polyamide filaments by twisting under tension until induced coiling, then twisting the coil in the opposite direction under reduced load (untwisting) and heat setting. The coiling index was measured and found to be approximately 2.9, and the axial linear thermal expansion coefficient of the fiber actuator was measured and found to be -4.2 mm / m / K.

[0126] In Figure 14, highly twisted fiber coils were fabricated from 0.1 mm polyamide filaments by twisting them under tension before inducing coiling, then winding them around a sacrificial fiber core, followed by heat setting and removal of the core. The coiling index was measured and found to be approximately 2.8, and the linear thermal expansion coefficient in the axial direction of the fiber actuator was measured and found to be -4.6 mm / m / K. Both coiled fiber actuators were fabricated from the same polyamide filament, and both coils are homochiral, have negative thermal expansion coefficients, and expand on cooling but not on heating. The coils coiled by twisting the material (Figure 13) show small spaces between each other, while the coils coiled by wrapping the material (Figure 14) are touching or nearly touching.

[0127] Additional Examples Using these techniques described above, thermal actuators have been produced with CTE values ​​on the order of magnitude of greater than 5 mm / m / K (for coils with negative thermal expansion, this means values ​​less than -5 mm / m / K or less than -0.005 / K), and actuators have also been produced with CTE values ​​on the order of magnitude of greater than 2 mm / m / K. Any of these example embodiments can be used to create responsive woven fabrics that operate near body temperature and are suitable for apparel applications.

[0128] FIG. 19 shows the effective coefficient of linear thermal expansion (CTE) data for over 200 twisted and coiled homochiral fiber actuators with various coil index values ​​(C). The dashed lines represent linear fits to the data (R 2=0.7). There is no data for mandrel wound or core wound actuators, all data represents coils made through twisting until coiling occurs. To obtain coil index values ​​above about 1.75, as-formed coils were partially untwisted to improve both the coil index value and the degree of linear expansion coefficient. Generally, coils with higher coil spring index (C) have coil contact temperatures high enough to allow expansion and contraction near body temperature. These improved spring index coils made with different materials and under different conditions also show variability in coil spacing and coil bias angle, which explains some of the larger data scatter at the higher C values. The data represents coils made from polyamides, polyesters and polyolefins fibers with various fiber or yarn sizes ranging from 0.05 mm to over 0.3 mm in diameter. The data also represents coils that were heat set under various conditions.

[0129] Table 1 summarizes the measured thermal expansion coefficient data from a series of twisted and coiled polyester fiber actuators heat set at different temperatures. Six fiber actuators were fabricated for each annealing temperature of 140°C, 170°C, and 200°C (18 fiber actuators in total). All actuators were fabricated under similar conditions and were nominally identical prior to the annealing step. At each temperature, half of the annealed fiber actuators were S-twisted homochiral actuators and half were Z-twisted homochiral actuators. All three heat-setting conditions were suitable for producing thermally responsive materials with large strokes, although the lower temperatures (140°C and 170°C) produced fiber actuators with significantly greater degrees of thermal response. Each heat-setting procedure was performed for 2 hours. TIFF0007604421000001.tif26143 Table 1: Summary data for twisted and coiled polyester fiber actuators heat set at different temperatures.

[0130] Lower heat setting conditions can also be used for materials with higher melting points. For example, autoclave conditions (121°C saturated and pressurized steam for 15-20 minutes) may be sufficient to loosen much of the twist tension of highly twisted polyamides, thereby reducing the tension required to reliably process highly twisted and / or coiled materials. Generally, it is desirable to heat set above the glass transition temperature of the material, which is typically less than 100°C for common polymers used in woven fabrics, such as polyesters and polyamides. For polyolefin materials, the glass transition temperature can be much lower, often less than 0°C, and heat setting temperatures below 100°C are often sufficient.

[0131] Using the techniques described herein, it has been shown that twisting the fiber to induce coiling can produce homochiral coiled fiber actuators with effective linear thermal expansion coefficient values ​​greater than -9 mm / m / K. Additional optimization is possible, and such values ​​are not an upper limit on performance. Furthermore, methods of wrapping twisted fibers around a core can produce similar results, and in some instances allow for greater control over the structure of the coils produced, thereby paving the way for improved performance.

[0132] The embodiments of the present disclosure can be described in terms of the following items (clauses). (Item 1) 1. A method of constructing a thermally adaptive garment configured to be worn and at least partially cover a portion of a user's body, comprising: creating a plurality of coiled actuator fibers; creating a thermally adaptive textile comprising a plurality of the created coiled actuator fibers; creating a garment body defined by the thermally adaptable fabric; Equipped with Each of the plurality of coiled actuator fibers comprises: The fibers are twisted to obtain a fiber bias angle α 繊維 To produce a highly twisted fiber having a twist angle of 25° to 50°, winding the highly twisted fiber around a sacrificial core to create a coil in the highly twisted fiber; setting the highly twisted coil of fiber disposed on the sacrificial core by applying heat or a chemical setting agent to the highly twisted coil of fiber; removing the sacrificial core by dissolving the sacrificial core in a solvent; Coil spring index (C) of 2.0 or more, Coil part contact temperature above 20℃, Thermal response of |CTE|≧2mm / m / K, Fiber bias angle α of 25°~50° 繊維 , and producing a coiled actuator fiber having the following characteristics: It is made by The garment body includes: an inner portion having an inner surface configured to face the body of a wearer; an exterior portion having an exterior surface configured to face an external environment of the wearer; the thermally adaptive fabric is configured to assume a primary configuration in response to a first environmental temperature range; The method of claim 1, wherein the thermally adaptive fabric is configured to assume a lofted configuration in response to a second environmental temperature range distinct from the first environmental temperature range. (Item 2) 2. The method of claim 1, wherein the fiber comprises one of a yarn comprising one or more fibers or a fiber comprising a single elongated element. (Item 3) 3. The method of claim 1 or 2, wherein the sacrificial core is removed through dissolution in water. (Item 4) 4. The method of any of claims 1 to 3, wherein the sacrificial core comprises a monofilament, filament yarn or staple yarn of a water-soluble polymer. (Item 5) 5. The method of any of the preceding claims, wherein the sacrificial core is removed after the coiled actuator fiber is incorporated into a fabric. (Item 6) 1. A method of making a plurality of coiled actuator fibers, comprising: Each of the plurality of coiled actuator fibers comprises: The fibers are twisted to obtain a fiber bias angle α 繊維 producing a twisted fiber having a twist angle of 25° to 50°; winding the twisted fiber around a sacrificial core to create a coil in the twisted fiber; setting the highly twisted coil of fiber disposed on the sacrificial core by applying heat or a chemical setting agent to the coil of twisted fiber; removing the sacrificial core by dissolving the sacrificial core in a solvent, Coil spring index (C) of 2.0 or more, Coil part contact temperature above 20℃, Thermal response of |CTE|≧2mm / m / K, Fiber bias angle α of 25°~50° 繊維 , and producing a coiled actuator fiber having two or more of the following characteristics: A method produced by the method. (Item 7) 7. The method of claim 6, wherein the fiber comprises one of: a yarn comprising one or more fibers or other elements; a fiber comprising a single elongated element. (Item 8) 1. A method of making a coiled actuator fiber, comprising: twisting the fibers to produce twisted fibers; winding the twisted fibers around a core to create a coil of the twisted fibers; removing at least a portion of the core to form a coiled actuator fiber; The method includes: (Item 9) 9. The method of claim 8, wherein the fiber comprises one of a yarn comprising one or more fibers or a fiber comprising a single elongated element. (Item 10) setting the coiled actuator fiber by thermal or chemical treatment. 10. The method according to item 8 or 9, further comprising: (Item 11) Item 11. The method of item 10, wherein the step of setting the twisted fiber coil occurs before partially or completely removing the core. (Item 12) Item 11. The method of item 10, wherein the step of setting the twisted fiber coil occurs on a spool of the coiled actuator fiber. (Item 13) 13. The method of any of items 8 to 12, wherein the coiled actuator fiber has a coil spring index (C) of 2.0 or more. (Item 14) 14. The method of any one of items 8 to 13, wherein the coil portion contact temperature of the coiled actuator fiber is 10° C. or higher. (Item 15) 15. The method of any of items 8 to 14, wherein the thermal response of the coiled actuator fiber is |CTE|≧2 mm / m / K. (Item 16) winding at least two twisted fibers around a core to create a coil of said twisted fibers. 16. The method according to any one of items 8 to 15, further comprising: (Item 17) a.Dissolution, b. Chemical reactions, or C. A combination of these 17. The method according to any of items 8 to 16, wherein the core is removed through (Item 18) 18. The method of claim 17, wherein the core further comprises a non-removable portion that is insoluble or chemically unreactive under the same conditions as the removable portion, and a portion of the core remains. (Item 19) The step of twisting the fiber to produce the twisted fiber includes twisting the fiber to produce a fiber bias angle α 繊維 19. The method according to any one of items 8 to 18, comprising the step of: (Item 20) The step of twisting the fiber to produce the twisted fiber includes twisting the fiber to produce a fiber bias angle α 繊維 20. The method according to any one of items 8 to 19, comprising a step of adjusting the angle to 30° to 40°. (Item 21) a. The coiled fiber is at body temperature and b. When in a no-load state, 1. A method of making a coiled fiber actuator having physical spaces between the coils, comprising: during a setting process, the coiled fiber actuator is placed under physical constraints that prevent substantial expansion or contraction of the coiled fiber actuator; C. Heat or d. Chemical treatment The method is set by at least one of (Item 22) 22. The method of claim 21, wherein the coiled actuator fiber has a coil spring index (C) of 2.0 or greater. (Item 23) 23. The method of claim 21 or 22, wherein the thermal response of the coiled fiber actuator is |CTE|≧2 mm / m / K. (Item 24) 24. The method of any of claims 21 to 23, wherein the physical constraint applied during setting is applied to a spool of the coiled fiber actuator. (Item 25) The physical constraint applied during the set includes: c. preventing substantial expansion or contraction of the coiled fiber actuator during the setting process; and 25. The method of any of claims 21-24, further comprising: holding the coiled fiber actuator in a position where there is a physical space between its coils. (Item 26) 26. The method of any of claims 21 to 25, wherein the coiled fiber actuator is heat set at a temperature of 121°C or greater. (Item 27) c. the coiled fiber is at room temperature; d. When in no-load condition, 27. The method of any one of claims 21 to 26, wherein the coiled fiber actuator has physical spaces between its coils. (Item 28) c. The coiled fiber is at body temperature and d. When in no-load condition, 1. A method of making a coiled fiber actuator having physical spaces between the coils, comprising: After initially forming the coil, the coiled fiber actuator is d. in a direction opposite to the twist direction used to form the coil; e. under tension less than that applied to the fiber when it was first coiled; f. To the extent that most of the coils formed initially remain intact, Twisted, the partially untwisted coiled fiber actuator comprising: C. Heat or d. Chemical treatment The method is set by at least one of (Item 29) 29. The method of claim 28, wherein the coiled actuator fiber has a coil spring index (C) of 2.0 or greater. (Item 30) 30. The method of claim 28 or 29, wherein the thermal response of the coiled fiber actuator is |CTE|≧2 mm / m / K. (Item 31) 31. The method of any of claims 28 to 30, wherein the coiled fiber actuator is heat set at a temperature of 121°C or greater. (Item 32) e. the coiled fiber is at room temperature; f. When in no-load condition, Item 32. The method of any one of items 28 to 31, wherein the coiled fiber actuator has physical spaces between its coils. (Item 33) g. The coiled fiber is at body temperature and h. When in no-load condition, 1. A method of making a coiled fiber actuator having physical spaces between the coils, comprising: The coiled fiber actuator comprises: d. twisting the fibers to produce twisted fibers; e. winding the twisted fiber around a sacrificial core to create a coil in the twisted fiber; f. Removing at least a portion of the sacrificial core to create a coiled actuator fiber. It is made by The coiled fiber actuator comprises: C. Heat or d. Chemical treatment The method is set by at least one of (Item 34) 34. The method of claim 33, wherein the core is removed through dissolution. (Item 35) 35. The method according to claim 33 or 34, wherein the core is completely removed. (Item 36) 36. The method of any of claims 33 to 35, wherein the twisted fibers are set before being wrapped around a core to create a coil. (Item 37) 37. The method of any of claims 33 to 36, wherein the fiber bias angle of the twisted fibers is 20° or more. (Item 38) 38. The method of any of items 33 to 37, wherein the thermal response of the coiled fiber actuator is |CTE|≧2 mm / m / K. (Item 39) 39. The method of any of claims 33 to 38, wherein the coiled fiber actuator is heat set prior to removing the core. (Item 40) i. the coiled fiber is at room temperature; j. When in no-load condition, 40. The method of any of claims 33-39, wherein the coiled fiber actuator has physical spaces between its coils. (Item 41) 1. A coiled fiber or yarn actuator made from a highly twisted fiber or yarn wrapped or coiled around a sacrificial core, A coiled fiber or coiled yarn actuator, wherein the sacrificial core has been partially or completely removed. (Item 42) Item 42. The coiled fiber actuator or coiled yarn actuator of item 41, wherein the fiber bias angle is between 25° and 45°. (Item 43) Item 43. The coiled fiber or coiled yarn actuator of item 41 or 42, wherein the sacrificial core is removed through dissolution. (Item 44) Item 44. The coiled fiber or coiled yarn actuator of any of items 41 to 43, wherein the sacrificial core is removed through dissolution in water. (Item 45) 45. The coiled fiber actuator or coiled yarn actuator of any of claims 41 to 44, wherein the sacrificial core is a monofilament, filament yarn or staple fiber yarn of a water soluble polymer. (Item 46) 46. ​​The coiled fiber or coiled yarn actuator of any of claims 41 to 45, wherein the coiled fiber or coiled yarn actuator has been set by thermal or chemical means prior to removing the sacrificial core. (Item 47) 1. A method of making a coiled fiber or coiled yarn actuator, comprising: a. twisting a fiber or yarn; b. wrapping or coiling the twisted fiber or yarn around a sacrificial core; c. partially or completely removing the sacrificial core; The method includes: (Item 48) 1. A method for altering a coil shape in a coiled fiber actuator or coiled yarn actuator, comprising: d. applying a tension equal to or less than the tension applied during formation of the coil; e. untwisting the coil to increase a coil index of the coiled fiber actuator or coiled yarn actuator; The method includes: (Item 49) Item 49. The method of claim 48, wherein the tension applied during untwisting is less than 50% of the tension applied during formation of the coil. (Item 50) During untwisting, a diameter of the coil is monitored; f.Tension, g. Winding speed, or h.Twisting speed 50. The method of claim 48 or 49, wherein the diameter data is used in controlling at least one of the process parameters: (Item 51) 1. A coiled fiber or yarn actuator made from a highly twisted fiber or yarn, comprising: coiled through insertion of twist under a first tension; A coiled fiber actuator or coiled yarn actuator untwisted under a second tension sufficient to change the coil index of the coiled fiber actuator or coiled yarn actuator. (Item 52) 52. The coiled fiber actuator or coiled yarn actuator of claim 51, wherein a second coiled fiber actuator or coiled yarn actuator made under identical twisting, coiling, and setting conditions, but without the untwisting step, has a lower coil contact temperature than the coil made from the same process including the untwisting step. (Item 53) i. A coil index of 2.0 or greater; or j. Coil contact temperature above room temperature 53. The coiled fiber actuator or coiled yarn actuator of claim 51 or 52, having at least one of (Item 54) 1. A method of making a coiled fiber or coiled yarn actuator, comprising: k. twisting the fiber or yarn under a first tension; ii. coiling the twisted fiber or yarn by either i. inserting twist until coiled, or ii. winding the twisted fiber or yarn around a sacrificial core or mandrel to coil; m. untwisting the coil under a second tension; The method includes: (Item 55) 55. The method of claim 54, wherein the second tension is less than the first tension. (Item 56) 56. The method of claim 54 or 55, wherein the second tension is 10% or less of the first tension. (Item 57) n. The coiled actuator is above room temperature; and o. No load condition; A coiled fiber actuator or coiled yarn actuator having physical spaces between the coils, Under physical restraints that prevent substantial expansion or contraction during the setting process, k. Heat or l. Chemical treatment a coiled fiber actuator or a coiled yarn actuator, the coiled fiber actuator or the coiled yarn actuator being set by at least one of (Item 58) Item 58. The coiled fiber or coiled yarn of item 57, wherein the coiled fiber or coiled yarn actuator before setting has coils in contact with adjacent coils at room temperature. (Item 59) 59. The coiled fiber or coiled yarn of item 57 or 58, wherein the coiled fiber actuator or coiled yarn actuator prior to setting is under minimal tension. (Item 60) p. relative or absolute fiber or yarn diameter; q. Fiber or yarn speed and r. the twist position of the fiber or yarn; A sensor comprising a camera and image analysis for determining at least one from a list of d. tension; e. Winding speed and f. twisting speed; a sensor that provides production control information regarding at least one process variable from the list of process variables used in the manufacture or processing of the fiber or yarn. (Item 61) 61. A textile actuator made by the process using the sensor described in item 60. (Item 62) A fiber actuator having a coil index value of 2.0 or greater, the coil being fabricated through twist insertion until a tubular twist is induced. (Item 63) Item 63. The fiber actuator of item 62, wherein the coil contact temperature is greater than 20° C.

Claims

1. 1. A method of making a coiled actuator fiber, comprising: twisting the fibers to produce twisted fibers; winding the twisted fiber around a core yarn or fiber to create a coil in the twisted fiber, thereby producing a coiled twisted fiber; setting the coiled, twisted fiber by thermal or chemical treatment; removing at least a portion of the core yarn or fiber to produce a coiled actuator fiber; Equipped with The coiled actuator fiber has a coil spring index (C) greater than 1.

7. A method comprising:

2. 1. A method of making a coiled actuator fiber, comprising: twisting the fibers to produce twisted fibers; winding the twisted fiber around a core yarn or fiber to create a coil in the twisted fiber to produce a coiled twisted fiber; setting the coiled, twisted fiber by thermal or chemical treatment; removing at least a portion of the core yarn or fiber to produce a coiled actuator fiber; Equipped with The coiled actuator fiber has a coefficient of thermal expansion greater than or equal to 1000 μm / m / K. A method comprising:

3. 1. A method of making a coiled actuator fiber, comprising: twisting the fibers to produce twisted fibers; winding the twisted fiber around a core yarn or fiber to create a coil in the twisted fiber, thereby producing a coiled twisted fiber; setting the coiled, twisted fiber by thermal or chemical treatment; removing at least a portion of the core yarn or fiber to produce a coiled actuator fiber; Equipped with The spacing between adjacent coils of the coiled actuator fiber is such that thermal activation of the coiled actuator fiber at 10° C. or greater under no load will cause the adjacent coils to contact each other. A method comprising:

4. At least a portion of the core yarns or fibers are removed by at least one of the following: (a) Dissolution (b) Chemical Reaction (c) Melting 4. The method according to claim 1, wherein the first and second electrodes are connected to a first electrode.

5. The winding direction is the same as the twisting direction.

5. A method according to any one of claims 1 to 4.

6. The wrapping direction is opposite to the twisting direction.

5. A method according to any one of claims 1 to 4.

7. The step of setting the coiled twisted fiber is performed prior to the step of removing at least a portion of the core yarn or fiber to produce the coiled actuator fiber.

7. A method according to any one of claims 1 to 6.

8. twisting the fibers to produce twisted fibers; winding the twisted fiber around a core yarn or fiber to create a coil in the twisted fiber, thereby producing a coiled twisted fiber; setting the coiled, twisted fiber by thermal or chemical treatment; removing at least a portion of the core yarn or fiber to produce a coiled actuator fiber; 1. A method of constructing a thermally adaptive textile comprising the steps of: fabricating a thermally adaptive textile comprising a plurality of coiled actuator fibers produced by one or more of: The coiled actuator fiber is at least partially responsible for the thermal adaptability of the thermal adaptable fabric. A method comprising:

9. The step of removing at least a portion of the core yarn or fiber occurs after the step of fabricating a thermally adaptive textile comprising a plurality of coiled actuator fibers produced by at least a portion of the method of claim 1.

9. The method of claim 8.

10. The thermal adaptability of the thermally adaptable fabric increases the insulating capacity of the thermally adaptable fabric in response to a decrease in temperature of the surrounding environment in which the thermally adaptable fabric resides.

10. The method according to claim 8 or 9.

11. The thermally adaptive fabric is produced through a weaving or knitting process.

11. A method according to any one of claims 8 to 10.

12. The plurality of coiled actuator fibers have a coefficient of thermal expansion greater than or equal to 1000 μm / m / K.

12. A method according to any one of claims 8 to 11.

13. The plurality of coiled actuator fibers have a coefficient of thermal expansion greater than or equal to 2 mm / m / °C.

13. A method according to any one of claims 8 to 12.

14. twisting the fibers to produce twisted fibers; winding the twisted fiber around a core yarn or fiber to create a coil in the twisted fiber, thereby producing a coiled twisted fiber; setting the coiled, twisted fiber by thermal or chemical treatment; removing at least a portion of the core yarn or fiber to produce a coiled actuator fiber; 1. A method of constructing a thermally adaptive garment comprising: fabricating a thermally adaptive textile comprising a plurality of coiled actuator fibers produced by one or more of the following: The plurality of coiled actuator fibers are at least partially responsible for the thermal adaptability of the thermally adaptable garment. A method comprising:

15. The thermal adaptability of the thermally adaptive garment increases the insulating capacity of the thermally adaptive garment in response to a decrease in temperature of the surrounding environment in which the thermally adaptive garment resides.

15. The method of claim 14.

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