1161 results about "Shape-memory polymer" patented technology

An adaptive optic for refractive lens exchange or cataract patients. The intracapsular implant comprises an elastomeric monolith with an equilibrium memory shape that imparts to the capsular sac's periphery the natural shape of the capsule in an accommodated state. In one embodiment, the monolith carries a recessed deformable central lens portion having an ultralow modulus that allows for high accommodative amplitude in response to equatorial tensioning. In a preferred embodiment, the adaptive optic defines an anisotropic modulus with a plurality of on-axis, rotationally symmetric elastomer block portions each having a different Young's modulus. The invention further provides composite materials for enhancing deformation of lens curvature, including the use of auxetic polymeric materials and negative stiffness materials. In preferred embodiments, at least a portion of the lens is fabricated of a shape memory polymer that provides a memory shape and a temporary shape with a reduced cross-sectional shape for introduction into the patient's eye.

A self-expanding medical occlusion device treats a heart defect in a patient and is inserted into the body in minimally invasive fashion using a catheter system, and includes a braiding of thin threads which exhibits a first preliminarily definable shape as the occlusion device is being inserted into the patient's body and a second preliminarily definable shape in the implanted state, whereby the occlusion device is in a collapsed state in the first shape of the braiding and in an expanded state in the second shape of the braiding. The threads of braiding are composed of a shape memory polymer composite such that braiding deforms from a temporary shape to a permanent shape in consequence of an external stimulus, whereby the temporary shape is given in a first profile form of the braiding and the permanent shape is given in a second profile form of the braiding.

This invention relates to a orthopedic implant that comprises a shape memory polymeric material. The orthopedic implant can be fabricated or molded in a desired configuration selected to provide support or tension to bony structures. Examples of implantable devices include spinal rods, bone plates, and bone fixation cords. The orthopedic implant can be deformed to a second configuration different from the first configuration either prior to implantation or after implantation. When desired, the shape memory polymeric material can be induced to revert to it original molded configuration. This can compress the attached bony structure and / or promote arthrodesis.

A screen section has a valve assembly to control flow through it. The valve is open and has a closure spring held compressed by a shape memory material that responds to the presence of a specific well fluid or fluids so that its property changes to allow the spring to deliver the stored potential energy to the valve member to close it when the specific well fluid or fluids are detected. The preferred material is a shape memory polymer that, for example, is sensitive to the presence of water or methane and gets softer to release the potential energy source to operate the downhole tool.

An apparatus for controlling fluid flow in a wellbore includes a reactive element that reacts when exposed to a fluid and a flow control device configured to control a flow of the fluid. The flow control device may be actuated by a reaction of the reactive element to the fluid. In embodiments, the reactive element reacts by exhibiting a change in a material property. The reaction of the reactive element may be reversible. In embodiments, the reactive element may be a shape memory polymer. The flow control device may include an actuating element operably coupled to the reactive element. The reaction of the reactive element to a given fluid releases the actuating element to actuate the flow control device.

Catheter assembly including an elongate shaft comprising a thermoplastic polymer such as a thermoplastic shape memory polymer having a pre-selected glass transition temperature (Tg) and a means for heating the thermoplastic polymer, wherein the thermoplastic polymer is in a rubbery state at temperatures above the glass transition temperature and is in a glassy state at temperatures below the glass transition temperature. The elongate shaft may be selectively heated and cooled to provide sufficient flexibility and retention during a medical procedure.

A hood lift mechanism for reversibly increasing the energy absorption capability at appropriate force levels of a vehicle hood includes a vehicle hood; an active material in operative communication with the vehicle hood, wherein the active material comprises a shape memory alloy, a ferromagnetic shape memory alloy, a shape memory polymer, a magnetorheological fluid, an electroactive polymer, a magnetorheological elastomer, an electrorheological fluid, a piezoelectric material, an ionic polymer metal composite, or combinations comprising at least one of the foregoing active materials; and an activation device in operative communication with the active material, wherein the activation device is operable to selectively apply an activation signal to the active material and effect a reversible change in a property of the active material, wherein the reversible change results in an increased clearance distance between the vehicle hood and an underlying component.

A bistable electroactive polymer transducer is provided for electrically actuated deformation of rigid electroactive polymer members. The polymers have glass transition temperatures (Tg) above ambient conditions and turn into rubbery elastomers above Tg and have high dielectric breakdown strength in the rubbery state. They can be electrically deformed to various rigid shapes with maximum strain greater than 100% and as high as 400%. The actuation is made bistable by cooling below Tg to preserve the deformation. The dielectric actuation mechanism includes a pair of compliant electrodes in contact with a dielectric elastomer which deforms when a voltage bias is applied between the pair of electrodes. In some of the configurations, the dielectric elastomer is also a shape memory polymer. The deformations of such bistable electroactive polymers can be repeated rapidly for numerous cycles.

Devices for treatments of diseases and disorders associated with the gastrointestinal tract, especially the stomach, or urinogenital tract are described herein. Initially, the device is in a temporary form which is suitable for oral or rectal administration. After exposure to a stimulus, such as a temperature or pH change, the device changes shape to a permanent form, which allows it to become mechanically fixed in the stomach, esophagus or intestine. In one embodiment, the device is used to reduce the volume of the stomach, esophagus or intestine without interfering with the flow of the food through the gastrointestinal tract. The device may be used to help overweight patients lose weight and to deliver drugs to treat disorders and diseases in the in the stomach or intestine. The devices are manufactured from a stimuli-sensitive polymeric material, which is biocompatible and primarily adapted to the mechanical properties and geometry in the area to which it is applied. In the preferred embodiment, the material is a shape memory polymer. Depending on the desired application, the polymer may be either biodegradable or non-degradable.

Thermoplastic polyurethanes having an alternating sequence of hard and soft segments in which a nanostructured polyhedral oligomeric silsesquioxane diol is used as a chain extender to form a crystalline hard segment constituting SMPs. The polyurethanes are formed by reacting a polyol, a chain extender dihydroxyl-terminated POSS and a diisocyanate. The polyurethanes have multiple applications including for example, implants for human health care, drug delivery matrices, superabsorbant hydrogels, coatings, adhesives, temperature and moisture sensors, etc.