Item with at least one thermoprogrammable switching section for applications in contact with materials having high heat transfer coefficients
Inventors
Weigel, Thomas • Lendlein, Andreas • LUETZOW KAROLA, null • Lützow, Karola • Klein, Frank • Madbouly, Samy
Assignees
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Publication Number
US-8652621-B2
Publication Date
2014-02-18
Expiration Date
Abstract
The present invention provides an article with at least one switching segment. The switching segment comprises a shape-memory compound and an isolating region surrounding the shape memory compound. The present invention also provides a method of producing such an article.
Core Innovation
The invention relates to an article having at least one switching segment for EMF-induced thermally programmable switching in shape-memory polymers. Each switching segment includes a shape-memory compound comprising at least one thermo-programmable shape memory polymer and particles embedded therein, where the particles are suitable to heat up in an alternating electromagnetic field. The shape-memory compound is characterized by a thermal transfer coefficient h_schalt.
The switching segment further comprises an isolating region surrounding the shape-memory compound, where the isolating region has a thermal transfer coefficient h_iso. The isolating region is configured such that h_iso is lower than h_schalt, i.e., h_iso < h_schalt. This insulating arrangement is provided together with the thermo-programmable shape memory polymer and EMF-heatable particles to support the thermally programmable switching behavior.
In described implementations, the isolating region may include a smooth exterior surface and/or a fluid-impermeable surface. The isolating region can be provided with structural features such as pores across a cross-section with a pore size gradient, or with a foam/gas/porosity structure. The thermal transfer behavior is additionally constrained by relationships involving ratios such as h_iso/h_schalt and/or geometric relationships such as diameter ratios relevant for reaching a switching temperature under exposure conditions.
Claims Coverage
The independent claim is directed to an article with at least one switching segment that integrates an EMF-heatable thermo-programmable shape-memory compound with an isolating region that has a lower thermal transfer coefficient (h_iso < h_schalt). The dependent claims refine this with additional quantitative thermal-transfer and geometric constraints and with isolating-region structural and contextual limitations.
Thermo-programmable shape-memory compound with EMF-heatable particles and defined thermal transfer coefficient
An article with at least one switching segment, wherein the switching segment comprises a shape-memory compound including at least one thermo-programmable shape memory polymer and particles embedded therein suitable to heat up in an alternating electromagnetic field, and wherein the shape memory compound has a thermal transfer coefficient h_schalt.
Isolating region surrounding the shape-memory compound with lower thermal transfer coefficient
An isolating region surrounding the shape-memory compound, wherein the isolating region has a thermal transfer coefficient h_iso, and wherein h_iso < h_schalt.
Quantitative thermal-transfer relationship for insulation efficiency
An article configured such that the ratio h_iso/h_schalt is less than or equal to 0.1.
Isolating-region pore-size gradient across cross-section
An article wherein the isolating region includes pores arranged across its cross-section with a pore size gradient, where outer-region pores are, on average, smaller than inner-region pores.
Switching conditions tied to water exposure and alternating electromagnetic field ranges
An article wherein the at least one switching segment is configured with a specified diameter ratio so that at least one switching segment reaches its switching temperature when exposed to water and/or an alternating electromagnetic field of 245 to 265 kHz with a field strength of 10 to 16 kA/m.
Isolating region formation by foaming, spraying, and/or phase inversion
A method wherein the isolating region is formed by foaming, spraying, and/or phase inversion.
Thermal-transfer context from a contacting material
An article in contact with a material whose thermal transfer coefficient is greater than h_schalt.
Overall claim coverage is centered on integrating an EMF-heatable thermo-programmable shape-memory compound (h_schalt) with an isolating region having a lower thermal transfer coefficient (h_iso < h_schalt). Dependent features add quantitative and structural constraints, including numerical bounds on h_iso/h_schalt, isolating-region pore-size gradients, switching-temperature-related geometric relationships, isolating-region formation options, and contextual thermal-transfer conditions from contacting materials.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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