Microfluidic device, composition and method of forming

Patent metadata

Field	Value
Publication number	US-9238346-B2
Application number	US-58823609-A
Country	US
Kind code	B2
Filing date	Oct 8, 2009
Priority date	Oct 8, 2009
Publication date	Jan 19, 2016
Grant date	Jan 19, 2016

Abstract

A composition made of at least 60 wt. % of a thermoplastic elastomer resin and additives that are solid at least from 0-50° C., that has a Shore A hardness that is less than about 50 bears a patterned surface, the pattern comprising at least one microfluidic channel having a cross-sectional dimension smaller than 100 microns is a substrate for forming a microfluidic device. The chief advantages of such compositions are: its ability to bond in a sealing manner to smooth surfaces of many different compositions, its ease of manufacture and microstructure patterning, and its general impermeability to liquids.

First claim

What is claimed is:

1. A microfluidic device comprising:
(a) a first part made of a soft solid thermoplastic elastomer (TPE) composition comprising at least 60 wt. % solids comprising a thermoplastic elastomer resin and 40 wt. % or less liquids,
the soft solid TPE composition having a Shore A hardness that is less than 50 and the first part bearing a patterned surface, the pattern comprising at least one microfluidic channel;
(b) a second part comprising a first meeting surface, the first meeting surface covering enough of the patterned surface for enclosing at least part of the microfluidic channel and,
(c) a sealed contact between the patterned surface and the first meeting surface without an adhesive between the patterned surface and the first meeting surface, wherein a viscoelastic phase of the TPE produces intimate contacting of the patterned surface that results in a reversible bond producing the sealed contact with a first temperature, pressure, and time, where the bond is capable of being made irreversible when a greater temperature, pressure and/or time is applied,
wherein the soft solid TPE composition comprises oil free SEBS.

2. The device of claim 1 , wherein the soft solid TPE composition comprises at least 80 wt. % solids and balance liquid.

3. The device of claim 1 , wherein the soft solid TPE composition comprises at least 90 wt. % solids and balance liquid.

4. The device of claim 1 , wherein the soft solid TPE composition comprises at least 95 wt. % solids and balance liquid.

5. The device of claim 1 , wherein the oil free SEBS comprises 85-90% soft blocks.

6. The device of claim 1 , wherein the second part:
is composed of a similar or dissimilar composition as the first part and comprises a thermoplastic elastomer, plastic, glass or ceramic;
is in the form of a film;
is composed of a less flexible material than the first part to support the microfluidic device;
is composed of a material chosen for thermal resistance to support the microfluidic device at an elevated temperature;
has a second meeting surface bearing a pattern comprising at least one microfluidic channel having a cross-sectional dimension smaller than 100 microns; or,
any combination thereof.

7. The device of claim 1 , wherein the microfluidic channel:
extends between two ends, each end being one of the following: an input, an output, a junction or a chamber;
is a closed chamber;
has an aspect ratio between 1:10 and 10:1; or
has a negative profile.

8. The device of claim 1 , wherein the soft solid TPE composition has a thermal resistance greater than about 95° C.

9. A method for forming a microfluidic device comprising:
(a) providing a composition containing a thermoplastic elastomer resin comprising at least 60 wt. % solids comprising a thermoplastic elastomer resin and 40 wt. % or less liquids;
(b) placing the composition onto a relief mold having at least one ridge defined thereon for molding a microfluidic channel;
(c) heating the composition adjacent the mold to a temperature above a highest glass transition temperature of the thermoplastic elastomer at a pressure of less than 5 bars;
(d) cooling to form a first part made of a soft solid thermoplastic elastomer (TPE) composition: bearing a patterned surface; having a viscoelastic phase that exhibits liquid flow at temperatures below 200° C. and having a Shore A hardness that is less than 50;
(e) removing the first part bearing a patterned surface from the mold, the patterned surface having microfluidic channel;
(f) applying the first part to a second part, the second part comprising a first meeting surface, the first meeting surface covering enough of the patterned surface for enclosing at least part of the microfluidic channel; and,
(g) sealing the patterned surface to the first meeting surface without an adhesive between the patterned surface and the first meeting surface to form a sealed contact, wherein the viscoelastic phase produces intimate contacting of the patterned surface that results in a reversible bond producing the sealed contact with a first temperature, pressure, and time, where the bond is capable of being made irreversible when a greater temperature, pressure and/or time is applied,
wherein the thermoplastic elastomer provided in step (a) comprises oil free SEBS.

10. The method of claim 9 , wherein the soft solid TPE composition comprises at least 80 wt. % solids and balance liquid.

11. The method of claim 9 , wherein the at least one ridge of the relief mold extends between two of the following: junctions with one or more other ridges, raised structural features of the mold, and a mold limit aligned with an edge of the part.

12. The method of claim 9 , wherein the composition provided in step (a) is a solid, a film, a liquid, or a solution.

13. The method of claim 9 , wherein the second part:
is composed of a similar or dissimilar composition as the first part and comprises thermoplastic elastomer, plastic, glass or ceramic;
is in the form of a film;
is composed of a less flexible material than the first part, and provides support for the microfluidic device;
has a second meeting surface bearing a pattern comprising at least one microfluidic channel having a cross-sectional dimension smaller than 100 microns; or
any combination thereof.

14. The method of claim 9 , wherein the thermoplastic elastomer resin provided in step (a) has a viscoelastic phase that exhibits liquid-like flow throughout an intended operating temperature regime of the microfluidic device.

15. The method of claim 9 , wherein the soft solid TPE composition has a thermal resistance greater than about 95° C.

16. The method of claim 9 , wherein the pressure during heating the composition adjacent the mold is less than 1.5 bars.

17. The method of claim 9 , wherein the pressure during heating the composition adjacent the mold is atmospheric.

Assignees

• Roy Emmanuel
• Veres Teodor
• Nat Res Council Canada

Inventors

• Roy Emmanuel
• Veres Teodor

Classifications

• C08J2323/04

  Homopolymers or copolymers of ethene · CPC title

• C08J2325/08

  Copolymers of styrene (C08J2329/08, C08J2335/06, C08J2355/02 take precedence) · CPC title

• B32B3/30 Primary

  characterised by a layer formed with recesses or projections, e.g. {hollows, grooves, protuberances, ribs (apertured layer B32B3/266; layer with cavities or internal voids B32B3/26)} · CPC title

• C08J2323/20

  having four to nine carbon atoms · CPC title

• B29C71/02 Primary

  Thermal after-treatment {(B29C71/0063 and B29C71/0072 take precedence)} · CPC title