Article and method for temperature regulation using a thermosensitive reactive hydrogel material

Abstract

A temperature regulation and flow control device is described. A web of material, e.g., for a wet suit, has a layer of gel particles embedded in a flow control layer, preferably a foam matrix. A water permeable neoprene layer covers the flow control layer and allows water to enter the suit. The flow of water in the suit is regulated by the expansion and contraction of the gel as it undergoes a volume phase transition in response to a change in temperature. When the diver is in cold water, the cold water enters the foam substrate and the gel expands, causing permeability (i.e., flow) to decrease. Flow is restricted in response to cooling, and the foam substrate expands and tightens the fit of the wet suit. In warmer water, an opposite effect occurs, whereby the gel contracts and flow increases. The gel contracts relaxing the fit of the suit. A gel having a particular volume phase transition critical temperature is selected in order to maintain body temperature in a particular environment. This technology also can be used to control temperature in other applications.

What is claimed is:  
     
         1 . A method for controlling the flow of water in a material to maintain a medium in thermal contact with the material approximately at a predetermined temperature, the method comprising the steps of: 
 providing a layer of the material in thermal contact with the medium, the material containing particles of a gel embedded therein, the gel having a gel volume phase transition critical temperature (VPTCT) at about the predetermined temperature; and    providing a fluid for flow through the material to regulate the temperature of the medium,    wherein the gel particles in the material absorb the fluid and expand to restrict flow when the temperature of the fluid is below the gel volume phase transition critical temperature and contract and expel the fluid to allow flow when the temperature of the fluid is above the gel volume phase transition critical temperature.    
     
     
         2 . The method of  claim 1 , wherein the material is an open cell foam material.  
     
     
         3 . The method of  claim 1 , wherein the layer of the material includes gel particles in an amount approximately 5% to 80% by weight of total dry weight of the material.  
     
     
         4 . The method of  claim 1 , wherein the step of providing a layer of the material includes providing a wet suit to a diver.  
     
     
         5 . The method of  claim 4 , wherein the gel is a hydrogel powder having a VPTCT in the range of about 18° C. to about 25° C.  
     
     
         6 . The method of  claim 4 , wherein the layer of material includes gel particles in an amount approximately 5% to 80% by weight of total dry weight of the foam layer.  
     
     
         7 . The method of  claim 4 , wherein the gel particles are formed from a poly(N-isopropylacrylamide) gel.  
     
     
         8 . The method of  claim 4 , wherein the gel contains a hydrophobic monomer.  
     
     
         9 . A wet suit for controlling the flow of water to maintain a desired skin surface temperature of a wearer, the wet suit comprising: 
 an outer layer; and    an inner layer comprising gel particles embedded in a matrix, the gel having a gel volume phase transition critical temperature (VPTCT) at about the desired skin surface temperature,    wherein the gel particles in the matrix absorb the fluid and expand to restrict flow when the temperature of the fluid is below the gel volume phase transition critical temperature and contract and expel the fluid to allow flow when the temperature of the fluid is above the gel volume phase transition critical temperature.    
     
     
         10 . The wet suit of  claim 9 , wherein the matrix comprises a foam layer.  
     
     
         11 . The wet suit of  claim 9 , wherein the outer layer comprises neoprene.  
     
     
         12 . The wet suit of  claim 9 , further comprising a second inner layer inside of the inner layer, the second inner layer having a slick surface for contact with the wearer.  
     
     
         13 . The wet suit of  claim 9 , further comprising a second outer layer outside of the outer layer.  
     
     
         14 . The wet suit of  claim 9 , wherein the gel is a hydrogel having a VPTCT in the range of about 18° C. to about 25° C.  
     
     
         15 . The wet suit of  claim 9 , wherein the inner layer includes gel particles in an amount approximately 5% to 80% by weight of total dry weight of the matrix.  
     
     
         16 . The wet suit of  claim 9 , wherein the gel particles comprise poly(N-isopropylacrylamide).  
     
     
         17 . The wet suit of  claim 16 , wherein the gel particles contain a hydrophobic monomer.  
     
     
         18 . The wet suit of  claim 17 , wherein the hydrophobic monomer is N-tert-butylacrylamide.  
     
     
         19 . The wet suit of  claim 9 , wherein the VPTCT is about 18° C.  
     
     
         20 . An article comprising: 
 an outer layer; and    an inner layer comprising gel particles embedded in a matrix, the gel having a gel volume phase transition critical temperature (VPTCT) at about the desired skin surface temperature,    wherein the gel particles in the matrix absorb the fluid and expand when the temperature of the fluid is below the gel volume phase transition critical temperature and contract and expel the fluid when the temperature of the fluid is above the gel volume phase transition critical temperature.    
     
     
         21 . The article of  claim 20  wherein the matrix is a foam matrix.  
     
     
         22 . The article of  claim 20  in the form of a web of material.  
     
     
         23 . The article of  claim 20  in the form of a tubular member.