Reversible, discontinuous volume changes of ionized isopropylacrylamide cells

• US 4,732,930 A
• Filed: 05/20/1985
• Issued: 03/22/1988
• Est. Priority Date: 05/20/1985
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Hirokawa, Yoshitsugu, Tanaka, Toyoichi
• Primary Examiner(s): Schofer, Joseph L.
• Assistant Examiner(s): Mulcahy, Peter D.
• Application Number:
  US06/735,910
• Time in Patent Office: 1,037 Days
• Field of Search: 526/303.1, 526/306, 524/555, 524/812, 524/742, 524/744
• US Class Current: 524/742
• CPC Class Codes: C08F 220/54 Amides , e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
• CPC Class Codes: C08F 8/00 Chemical modification by after-treatment graft polymers, block polymers, crosslinking with unsaturated monomers or with polymers C08F251/00 - C08F299/00; of conjugated diene rubbers C08C
• CPC Class Codes: C08F 8/44 Preparation of metal salts or ammonium salts
• CPC Class Codes: C08J 2333/24 Homopolymers or copolymers of amides or imides
• CPC Class Codes: C08J 3/03 in aqueous media
• CPC Class Codes: G01N 27/44747 Composition of gel or of carrier mixture

Abstract

An ionic gel formed by polymerization of isopropylacrylamide in the presence of an ion-containing monomer, a crosslinking agent and a suitable liquid medium is provided. The gel is capable of drastic volume change in response to solvent composition, temperature, pH, or ion composition.

Claims

1. An ionic gel having a reversible phase transition function characterized by a drastic volume change in response to a change of liquid medium composition, temperature, pH or ion composition which comprises a polymerized product obtained by polymerization of isopropylacrylamide in the presence of an ion-containing monomer selected from the group consisting of a metal-containing acrylate and a metal containing methacrylate, a crosslink agent and a liquid medium selected from the groups consisting of water, a solvent compatible with water and a mixture of said solvent and water, said ion containing monomer being ion exchanged to replace said metal with hydrogen ion subsequent to said polymerization.

2. A non-ionic gel according to claim 1, in which said solvent compatible with water is a solvent selected from the group consisting of acetone, dioxane and dimethyl sulfoxide.

3. An ionic gel having a reversible phase transition function characterized by drastic volume change in response to a change of liquid medium composition, pH or ion composition or temperature which comprises a polymerized product obtained by polymerization of isopropylacrylamide and an ion-containing monomer selected from the group consisting of a metal containing acrylate and a metal containing methacrylate in the presence of N,-methylene-bisacrylamide and a liquid medium selected from the group consisting of water, a solvent compatible with water and a mixture of said solvent and water, said ion container monomer being ion exchanged to replace said metal with hydrogen ion subsequent to said polymerization.

4. A non-ionic gel according to claim 3, in which said solvent compatible with water is a solvent selected from the group consisting of acetone, dioxane and dimethyl sulfoxide.