# US 12,179,189 B2 · Film for microfluidic device, microfluidic device and method for manufacturing same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,179,189 B2 - Document ID: US12179189B2 - Status: Granted - Kind: B2 - Application number: 17/415,988 - Filed: 2019-12-20 - Published: 2021-12-09 - Granted: 2024-12-31 - Earliest claimed: 2018-12-26 - Assignees: Solventum Intellectual Properties Company - Applicants: Solventum Intellectual Properties Company - Inventors: Takeshi Ito; Yasushi Ebihara; Naota Sugiyama - Web page: https://patentgrep.com/patent/US12179189B2 ## CPC - B01L 3/502707: {characterised by the manufacture of the container or its components} - B01L 2200/0689: Sealing - B01L 2200/12: Specific details about manufacturing devices - B01L 2300/0887: Laminated structure - B01L 2300/12: Specific details about materials - B01L 2300/161: Control and use of surface tension forces, e.g. hydrophobic, hydrophilic - B01L 2300/168: Specific optical properties, e.g. reflective coatings - B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE ## Abstract A film for a microfluidic device is capable of bonding to a polydimethylsiloxane substrate having flow channels formed in a surface thereof, and also exhibiting stable hydrophilicity even under high temperature and high humidity conditions and having scratch resistance. When the film can be used as a microfluidic device, the film is bonded to a polydimethylsiloxane substrate having flow channels formed in a surface thereof to form a liquid-tight flow channels. The film including a base material and a hydrophilic coating, wherein the hydrophilic coating includes a (meth)acrylic resin and from 65 to 95 mass % of unmodified nanosilica particles based on a total mass of the hydrophilic coating. ## Claims ### Claim 1 A film for a microfluidic device, comprising: a base material; and a hydrophilic coating; wherein the hydrophilic coating comprises a (meth)acrylic resin and from 65 to 95 mass % of unmodified nanosilica particles based on a total mass of the hydrophilic coating, the unmodified nanosilica particles being non-agglomerated in the (meth)acrylic resin. ### Claim 2 (depends on 1) The film according to claim 1, wherein an initial water contact angle of the hydrophilic coating is 30 degrees or less. ### Claim 3 (depends on 1) The film according to claim 1, wherein the hydrophilic coating has a water contact angle of 30 degrees or less when the film is left for 30 days at 40° C. and a relative humidity of 75%. ### Claim 4 (depends on 1) The film according to claim 1, wherein the hydrophilic coating has a surface roughness of 3 nm or less. ### Claim 5 (depends on 1) The film according to claim 1, wherein a Δhaze value of the hydrophilic coating is from −1.5% to 1.5%, and the Δhaze value is a value obtained by subtracting an initial haze value (%) from a haze value (%) after 10 cycles of a steel wool abrasion resistance test using a #0000 steel wool and a weight of 350 g. ### Claim 6 (depends on 1) The film according to claim 1, wherein the (meth)acrylic resin has at least one moiety selected from the group consisting of an ethylene oxide moiety and a propylene oxide moiety. ### Claim 7 (depends on 1) The film according to claim 1, wherein the hydrophilic coating further comprises a silane coupling agent. ### Claim 8 (depends on 1) The film according to claim 1, wherein the hydrophilic coating has a thickness of 0.05 μm to 10 μm. ### Claim 9 (depends on 1) The film according to claim 1, wherein the base material is a polyethylene terephthalate film. ### Claim 10 (depends on 1) The film according to claim 1, wherein the base material is transparent. ### Claim 11 (depends on 1) A microfluidic device comprising: a polydimethylsiloxane substrate having flow channels formed in a surface thereof; and the film of claim 1 covering the flow channels; wherein the polydimethylsiloxane substrate and the film are bonded such that the surface of the polydimethylsiloxane substrate in which the flow channels are formed faces the hydrophilic coating of the film, and liquid-tight flow channels are provided internally once the polydimethylsiloxane substrate and the film are bonded. ### Claim 12 (depends on 1) A method for manufacturing a microfluidic device, the method comprising: preparing a polydimethylsiloxane substrate having flow channels formed in a surface thereof; preparing the film described in claim 1; activating the surface of the polydimethylsiloxane substrate in which the flow channels are formed and the hydrophilic coating of the film; and bonding the polydimethylsiloxane substrate and the film such that the surface of the polydimethylsiloxane substrate in which the flow channels are formed faces the hydrophilic coating of the film, thereby forming liquid-tight flow channels within the microfluidic device. ### Claim 13 (depends on 12) The method according to claim 12, wherein the activation is carried out by exposure to oxygen plasma. ### Claim 14 (depends on 6) The film according to claim 6, wherein the (meth)acrylic resin is a di(meth)acrylate or a tri(meth)acrylate. ### Claim 15 (depends on 7) The film according to claim 7, wherein the silane coupling agent has an ethylenically unsaturated group. ### Claim 16 (depends on 11) The microfluidic device according to claim 11, wherein the (meth)acrylic resin has at least one moiety selected from the group consisting of an ethylene oxide moiety and a propylene oxide moiety. ### Claim 17 (depends on 16) The microfluidic device according to claim 16, wherein the (meth)acrylic resin is a di(meth)acrylate or a tri(meth)acrylate. ### Claim 18 (depends on 11) The microfluidic device according to claim 11, wherein the hydrophilic coating further comprises a silane coupling agent. ### Claim 19 (depends on 18) The microfluidic device according to claim 18, wherein the silane coupling agent has an ethylenically unsaturated group.