# US 9,434,133 B2 · Microcapsules adapted to rupture in a magnetic field to enable easy removal of one substrate from another for enhanced reworkability > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,434,133 B2 - Document ID: US9434133B2 - Status: Granted - Kind: B2 - Application number: 14/930,336 - Filed: 2015-11-02 - Published: 2016-02-25 - Granted: 2016-09-06 - Earliest claimed: 2011-08-05 - Assignees: International Business Machines Corporation - Applicants: International Business Machines Corporation - Inventors: Dylan J. Boday; Joseph Kuczynski; Robert E. Meyer, III - Web page: https://patentgrep.com/patent/US9434133B2 ## CPC - B01J 13/18: In situ polymerisation with all reactants being present in the same phase - B32B 9/04: comprising such {particular} substance as the main or only constituent of a layer, {which is} next to another layer of {the same or of} a {different material (next to a glass layer B32B17/06; layered products with at least two ceramic layers composed mainly of ceramic B32B18/00)} - B32B 43/006: {Delaminating} - C09K 5/08: Materials not undergoing a change of physical state when used (C09K5/16, C09K5/20 take precedence) - H01F 1/0054: {Coated nanoparticles, e.g. nanoparticles coated with organic surfactant} - B32B 2264/02: Synthetic macromolecular particles - B32B 2307/208: Magnetic, paramagnetic - B32B 2457/00: Electrical equipment - Y10T 156/1111: Using solvent during delaminating [e.g., water dissolving adhesive at bonding face during delamination, etc.] - Y10T 428/31663: As siloxane, silicone or silane - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract An enhanced thermal interface material (TIM) gap filler for filling a gap between two substrates (e.g., between a coldplate and an electronics module) includes microcapsules adapted to rupture in a magnetic field. The microcapsules, which are distributed in a TIM gap filler, each have a shell that encapsulates a solvent. One or more organosilane-coated magnetic nanoparticles is/are covalently bound into the shell of each microcapsule. In one embodiment, (3-aminopropyl) trimethylsilane-coated magnetite nanoparticles are incorporated into the shell of a urea-formaldehyde (UF) microcapsule during in situ polymerization. To enable easy removal of one substrate affixed to another substrate by the enhanced TIM gap filler, the substrates are positioned within a magnetic field sufficient to rupture the microcapsule shells through magnetic stimulation of the organosilane-coated magnetic nanoparticles. The ruptured microcapsule shells release the solvent, which dissolves and/or swells the TIM gap filler, thereby reducing the bond strength between the substrates. ## Claims ### Claim 1 An apparatus, comprising: a first substrate; a second substrate; an enhanced thermal interface (TIM) gap filler disposed in a gap between the first substrate and the second substrate, wherein the enhanced TIM gap filler comprises a TIM gap filler and microcapsules distributed in the TIM gap filler, wherein each microcapsule has a shell encapsulating a solvent and into which one or more organosilane-coated magnetic nanoparticles is/are covalently bound. ### Claim 2 (depends on 1) The apparatus as recited in claim 1, wherein the first substrate is a coldplate and the second substrate is an electronics module. ### Claim 3 (depends on 2) The apparatus as recited in claim 2, wherein the microcapsules include urea-formaldehyde (UF) microcapsules each having a shell into which one or more (3-aminopropyl) trimethylsilane-coated magnetite nanoparticles is/are covalently bound. ### Claim 4 (depends on 3) The apparatus as recited in claim 3, wherein the shell of each UF microcapsule encapsulates toluene. ### Claim 5 (depends on 3) The apparatus as recited in claim 3, wherein the solvent is selected to dissolve and/or swell the TIM gap filler when the solvent is released from encapsulation upon rupture of the microcapsules in a magnetic field. ### Claim 6 An apparatus, comprising: a coldplate; an electronics module; an enhanced thermal interface (TIM) gap filler disposed in a gap between the coldplate and the electronics module, wherein the enhanced TIM gap filler comprises a TIM gap filler and microcapsules distributed in the TIM gap filler, wherein each microcapsule has a shell encapsulating a solvent and into which one or more organosilane-coated magnetic nanoparticles is/are covalently bound so that the one or more organosilane-coated magnetic nanoparticles is/are embedded in the shell of each of the microcapsules. ### Claim 7 (depends on 6) The apparatus as recited in claim 6, wherein the microcapsules include urea-formaldehyde (UF) microcapsules each having a shell into which one or more (3-aminopropyl) trimethylsilane-coated magnetite nanoparticles is/are covalently bound. ### Claim 8 (depends on 7) The apparatus as recited in claim 7, wherein the shell of each UF microcapsule encapsulates toluene. ### Claim 9 (depends on 7) The apparatus as recited in claim 7, wherein the solvent is selected to dissolve and/or swell the TIM gap filler when the solvent is released from encapsulation upon rupture of the microcapsules in a magnetic field. ### Claim 10 An apparatus, comprising: a coldplate; an electronics module; an enhanced thermal interface (TIM) gap filler disposed in a gap between the coldplate and the electronics module, wherein the enhanced TIM gap filler comprises a TIM gap filler and urea-formaldehyde (UF) microcapsules distributed in the TIM gap filler, wherein each UF microcapsule has a shell encapsulating a solvent and into which one or more (3-aminopropyl) trimethylsilane-coated magnetite nanoparticles is/are covalently bound so that the one or more (3-aminopropyl) trimethylsilane-coated magnetite nanoparticles is/are embedded in the shell of each of the UF microcapsules. ### Claim 11 (depends on 10) The apparatus as recited in claim 10, wherein the shell of each UF microcapsule encapsulates toluene. ### Claim 12 (depends on 10) The apparatus as recited in claim 10, wherein the solvent is selected to dissolve and/or swell the TIM gap filler when the solvent is released from encapsulation upon rupture of the microcapsules in a magnetic field.