STIMULUS RESPONSIVE POLYMERIC SYSTEM

• US 20160033389A1
• Filed: 07/02/2015
• Published: 02/04/2016
• Est. Priority Date: 07/03/2014
• Status: Active Grant

• Current Assignee: The Governors of the University of Alberta (University of Alberta)
• Original Assignee: The Governors of the University of Alberta (University of Alberta)
• Inventors: Serpe, Michael
• Granted Patent: US 9,759,648 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01N 19/10 Measuring moisture content, e.g. by measuring change in length of hygroscopic filament; Hygrometers
• CPC Class Codes: G01N 5/025 for determining moisture content

Abstract

Herein, a polymer-based device capable of lifting many times its own mass was fabricated by drying a solution of the polycation poly (diallyldimethyl ammonium chloride) (pDADMAC) on a surface coated with charged poly (N-isopropylacrylamide)-based microgels. Due to strong polymer-polymer and polymer-surface interactions, when the pDADMAC solution dries on the microgel-modified surface, it bends. If the surface is flexible, it curls up into a scroll like structure, that can be opened up at high (ca. 80%) humidity. This process is fully reversible, i.e., if the humidity is decreased, the surface curls back up. This expansion/contraction behavior is capable of lifting relatively large masses, many times its own mass, and can potentially be used as an artificial muscle.

Claims

1. A stimulus responsive device comprising:

a flexible substrate;

a porous intermediate layer attached to the flexible substrate; and

a stimulus responsive material bonded to the porous intermediate layer.

2. The stimulus responsive material of claim 1 in which the porous intermediate layer comprises a hydrogel.

3. The stimulus responsive material of claim 2 in which the hydrogel comprises pNIPAm or polyhydroxyethyl methacrylate.

4. The stimulus responsive device of claim 1 in which the stimulus responsive material is responsive to a change in humidity.

5. The stimulus responsive device of claim 4 in which the stimulus responsive material comprises pDADMAC, polyallylamine hydrochloride, polyethylene amine or any positively charged polymer.

6. The stimulus responsive device of claim 1 further comprising a metal layer between the flexible substrate and the porous intermediate layer.

7. The stimulus responsive device of claim 6 in which the metal layer comprises a first metal adjacent to the flexible substrate and a second metal adjacent to the porous intermediate layer.

8. The stimulus responsive device of claim 7 in which the second metal comprises Au, Cu, Ni, Al, Ag or Ti.

9. The stimulus responsive device of claim 7 in which the first metal comprises Ti or Cr.

10. The stimulus responsive device of claim 1 in which the flexible substrate comprises a polymer.

11. The stimulus responsive device of claim 1 in which the stimulus responsive material is arranged in strips of respective widths, the respective widths chosen to cause bending at the strips of respective specified angles in response to a stimulus.

12. (canceled)

13. A stimulus responsive device comprising:

a flexible substrate; and

strips of a stimulus responsive material attached to the flexible substrate, in which the strips have respective widths chosen to cause bending at the strips of respective specified angles in response to a stimulus.

14. (canceled)

15. A method of measuring a stimulus, the method comprising:

subjecting a stimulus responsive device to a stimulus in which the stimulus responsive device comprises a flexible substrate, a porous intermediate layer attached to the flexible substrate; and

a stimulus responsive material bonded to the porous intermediate layer, wherein the stimulus causes a response of the stimulus responsive device; and

converting the response to a detectable signal.