Yarns of shape memory polymers and uses thereof

Abstract

This document relates to devices and methods for making and using shape memory polymer yarns. For example. this document relates to devices and methods for programming a deformed shape memory polymer yarn to return to an original shape and/or exert a force under certain conditions.

What is claimed is: 
     
         1 . A yarn comprising a plurality of monofilaments, wherein at least one monofilament comprises a shape memory polymer, and wherein the yarn is configured to generate a predetermined force (e.g., a predetermined compressive force), generate a predetermined strain, or generate a combination of force and strain. 
     
     
         2 . The yarn of  claim 1 , wherein the yarn is torque imbalanced. 
     
     
         3 . The yarn of  claim 1 , wherein the yarn is torque balanced. 
     
     
         4 . The yarn of  claim 1 , wherein the yarn comprises two, three, four, five, six, seven, eight, nine, ten, or more monofilaments. 
     
     
         5 . The yarn of  claim 1 , wherein the at least one monofilament is characterized as having a first stored configuration. 
     
     
         6 . The yarn of  claim 5 , wherein the first stored configuration comprises a non-linear shape (e.g., a curvilinear shape, a loop, etc.) formed by treating the at least one monofilament to a temperature between a glass transition temperature (T g ) and a melting temperature (T m ) of the shape memory polymer. 
     
     
         7 . The yarn of  claim 5 , wherein the first stored configuration comprises a linear shape formed by treating the at least one monofilament to a temperature between a glass transition temperature (T g ) and a melting temperature (T m ) of the shape memory polymer. 
     
     
         8 . The yarn of  claim 6 , wherein the at least one monofilament is characterized as having a second stored configuration that is different than the first stored configuration. 
     
     
         9 . The yarn of  claim 8 , wherein the at least one monofilament is configured to be actuated between the first and second stored configurations upon exposure to a stimulus. 
     
     
         10 . The yarn of  claim 9 , wherein the stimulus comprises a change in temperature (e.g., to an actuation temperature between T g  and T m  of the shape memory polymer). 
     
     
         11 . The yarn of  claim 1 , wherein the yarn is characterized as having a first stored configuration. 
     
     
         12 . The yarn of  claim 11 , wherein the first stored configuration comprises a non-linear shape (e.g., a curvilinear shape, a loop, etc.) formed by treating the yarn to a temperature between a glass transition temperature (T g ) and a melting temperature (T m ) of the shape memory polymer. 
     
     
         13 . The yarn of  claim 11 , wherein the first stored configuration comprises a linear shape formed by treating the yarn to a temperature between a glass transition temperature (T g ) and a melting temperature (T m ) of the shape memory polymer. 
     
     
         14 . The yarn of  claim 12 , wherein the yarn is characterized as having a second stored configuration that is different than the first stored configuration. 
     
     
         15 . The yarn of  claim 14 , wherein the yarn is configured to be actuated between the first and second stored configurations upon exposure to a stimulus. 
     
     
         16 . The yarn of  claim 15 , wherein the stimulus comprises a change in temperature (e.g., to an actuation temperature between T g  and T m  of the shape memory polymer). 
     
     
         17 . The yarn of  claim 1 , wherein at least one of the plurality of monofilaments is annealed (e.g., at an annealing temperature between T g  and T m  of the shape memory polymer). 
     
     
         18 . The yarn of  claim 1 , wherein the yarn is annealed (e.g., at an annealing temperature between T g  and T m  of the shape memory polymer). 
     
     
         19 . The yarn of  claim 1 , wherein at least one of the plurality of monofilaments is extruded, spun (e.g., by way of melt spinning, drying spinning, wet spinning, electrospinning, etc.), hot drawn (e.g., at a temperature between T g  and T m  of the shape memory polymer), cold drawn (e.g., at a temperature below T g  of the shape memory polymer), printed (e.g., 3D printed), and the like, as well as combinations thereof. 
     
     
         20 . The yarn of  claim 1 , wherein the shape memory polymer comprises poly (lactic acid) (PLA), poly (urethane), nylon, a copolymer of any of these, and/or a linear and/or branched polymer form of any of these. 
     
     
         21 . The yarn of  claim 1 , wherein the at least one monofilament is continuous along a predetermined length of the yarn (e.g., a predetermined length that is at least 50%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or more of a total length of the yarn). 
     
     
         22 . The yarn of  claim 1 , wherein the plurality of monofilaments is not entangled along a predetermined length of the yarn (e.g., a predetermined length that is at least 50%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or more of a total length of the yarn). 
     
     
         23 . The yarn of  claim 1 , wherein the yarn is characterized by a twist factor τ of about 10 to 150. 
     
     
         24 . A textile comprising the yarn of  claim 1 . 
     
     
         25 . The textile of  claim 24 , wherein the textile comprises a knit, woven, and/or braided textile. 
     
     
         26 . The textile of  claim 24 , wherein the textile comprises a garment (e.g., a compression garment, an athletic garment, a body shapewear, a shoe, a sock, a stocking, a sensory clothing, and the like), a suture, a stent, a graft (e.g., a tissue graft), a scaffold, a bandage, or a joint support. 
     
     
         27 . A method comprising:
 spinning a plurality of monofilaments to provide an initial yarn configured to generate a predetermined force (e.g., a predetermined compressive force), wherein at least one monofilament comprises a shape memory polymer.   
     
     
         28 . The method of  claim 27 , further comprising:
 plying the initial yarn to provide a torque balanced yarn or a torque imbalanced yarn.   
     
     
         29 . The method of  claim 27 , further comprising:
 optionally annealing the initial yarn, the torque balanced yarn, or the torque imbalanced yarn (e.g., at an annealing temperature between T g  and T m  of the shape memory polymer); and   programming at least a first stored configuration in the initial yarn, the torque balanced yarn, or the torque imbalanced yarn (e.g., using any process herein).   
     
     
         30 . The method of  claim 27 , wherein said spinning comprises increasing a twist factor of the initial yarn, the torque balanced yarn, or the torque imbalanced yarn (e.g., increasing a twist factor τ to about 10 to 150 or higher). 
     
     
         31 . The method of  claim 30 , wherein said increasing the twist factor provides an increase in strain of the initial yarn, the torque balanced yarn, or the torque imbalanced yarn (e.g., as compared to a yarn lacking the increased twist factor). 
     
     
         32 . The method of  claim 27 , wherein said increasing the twist factor provides an increase in strain of the initial yarn, the torque balanced yarn, or the torque imbalanced yarn (e.g., as compared to a yarn lacking the increased twist factor). 
     
     
         33 . The method of  claim 27 , further comprising (e.g., before said spinning):
 thermally and/or mechanically and/or chemically processing the plurality of monofilaments (e.g., by annealing, cold drawing, hot drawing, crosslinking, or combinations thereof).   
     
     
         34 . The method of  claim 27 , further comprising (e.g., before or after said spinning):
 thermally and/or mechanically and/or chemically processing the initial yarn, the torque balanced yarn, or the torque imbalanced yarn (e.g., by annealing, cold drawing, hot drawing, crosslinking, or combinations thereof).   
     
     
         35 . The method of  claim 27 , further comprising:
 knitting the yarn to form a textile, wherein the textile is configured to apply said predetermined force upon exposure to a stimulus.   
     
     
         36 . The method of  claim 28 , wherein the initial yarn, the torque balanced yarn, or the torque imbalanced yarn comprises the plurality of monofilaments.