A method for making a foamed article (265; 319), the method comprising: Placing an article (214; 216; 218; 405; 406; 407) and carbon dioxide in a vessel (234; 602), wherein the article (214; 216; 218; 405; 406; 407) comprises a solid foamable material (210; 502; 620a; 620b) which is a thermoplastic elastomeric material comprising one or more first thermoplastic elastomers; after the placing, maintaining the vessel (234; 602) at a first pressure and first temperature, wherein the first pressure and first temperature are a pressure and temperature at which the carbon dioxide (240; 246; 604) is a liquid and the liquid carbon dioxide (240; 246; 604) is soluble in the solid foamable material (210; 502; 620a; 620b), and wherein the maintaining includes holding the article (214; 216; 218; 405; 406; 407) and the liquid carbon dioxide (240; 246; 604) in the vessel (234; 602) for a duration of time sufficient for at least a portion of the liquid carbon dioxide (240; 246; 604) to infuse into the solid foamable material (210; 502; 620a; 620b) of the article (214; 216; 218; 405; 406; 407); following the maintaining and holding, optionally exposing the infused article (255; 256) to a second pressure and second temperature at which the carbon dioxide (240; 246; 604) remains infused within at least a portion of the solid foamable material (210; 502; 620a; 620b); following the maintaining and holding and the optional exposing, subjecting the article (255; 256) to a third pressure and third temperature at which the carbon dioxide (240; 246; 604) infused in the solid foamable material (210; 502; 620a; 620b) phase transitions to a gas, thereby expanding the solid foamable material (210; 502; 620a; 620b) into a foamed material (502; 620c) and forming the foamed article (265; 319); wherein the article (214; 216; 218; 405; 406; 407) comprises a first sheet and a second sheet, wherein a first side of the first sheet faces a second side of the second sheet, and characterized in that the first sheet and the second sheet are bonded together to form a plurality of internal cavities in a space between the first side of the first sheet and the second side of the second sheet, wherein the bond extends around at least a portion of a perimeter of each internal cavity, optionally wherein for each internal cavity (a) the bond is contiguous around only one or more portions of the perimeter of the internal cavity, and includes one or more apertures capable of admitting a fluid to the internal cavity, forming an open cavity, or (b) the bond is contiguous around an entire perimeter of the internal cavity, forming a sealed bladder capable of retaining a fluid in the internal cavity at a pressure above or below atmospheric pressure. Placing an article (214; 216; 218; 405; 406; 407) and carbon dioxide in a vessel (234; 602), wherein the article (214; 216; 218; 405; 406; 407) comprises a solid foamable material (210; 502; 620a; 620b) which is a thermoplastic elastomeric material comprising one or more first thermoplastic elastomers; after the placing, maintaining the vessel (234; 602) at a first pressure and first temperature, wherein the first pressure and first temperature are a pressure and temperature at which the carbon dioxide (240; 246; 604) is a liquid and the liquid carbon dioxide (240; 246; 604) is soluble in the solid foamable material (210; 502; 620a; 620b), and wherein the maintaining includes holding the article (214; 216; 218; 405; 406; 407) and the liquid carbon dioxide (240; 246; 604) in the vessel (234; 602) for a duration of time sufficient for at least a portion of the liquid carbon dioxide (240; 246; 604) to infuse into the solid foamable material (210; 502; 620a; 620b) of the article (214; 216; 218; 405; 406; 407); following the maintaining and holding, optionally exposing the infused article (255; 256) to a second pressure and second temperature at which the carbon dioxide (240; 246; 604) remains infused within at least a portion of the solid foamable material (210; 502; 620a; 620b); following the maintaining and holding and the optional exposing, subjecting the article (255; 256) to a third pressure and third temperature at which the carbon dioxide (240; 246; 604) infused in the solid foamable material (210; 502; 620a; 620b) phase transitions to a gas, thereby expanding the solid foamable material (210; 502; 620a; 620b) into a foamed material (502; 620c) and forming the foamed article (265; 319); wherein the article (214; 216; 218; 405; 406; 407) comprises a first sheet and a second sheet, wherein a first side of the first sheet faces a second side of the second sheet, and characterized in that the first sheet and the second sheet are bonded together to form a plurality of internal cavities in a space between the first side of the first sheet and the second side of the second sheet, wherein the bond extends around at least a portion of a perimeter of each internal cavity, optionally wherein for each internal cavity (a) the bond is contiguous around only one or more portions of the perimeter of the internal cavity, and includes one or more apertures capable of admitting a fluid to the internal cavity, forming an open cavity, or (b) the bond is contiguous around an entire perimeter of the internal cavity, forming a sealed bladder capable of retaining a fluid in the internal cavity at a pressure above or below atmospheric pressure.