Fluid permeable and vacuumed insulating microspheres and methods of producing the same

A method of making a fluid permeable microspheres, comprising:

• phase separating a glass comprised in an outer shell of a glass microspheres into a plurality of phases;
• leaching at least a soluble phase of said plurality of phases from the outer shell;
• forming a plurality of interconnected pores in said outer shell;
• obtaining a fluid permeable microspheres with a fluid permeable outer shell;
• evacuating fluid contents of a substantially hollow inner space of said fluid permeable microsphere enclosed by said fluid permeable outer shell and of the plurality of the interconnected pores of said fluid permeable outer shell;
• sealing said fluid permeable outer shell to maintain a vacuum in the substantially hollow inner space;
• wherein said outer shell enclosing the substantially hollow inner space;
• wherein said fluid permeable glass microsphere having an average particle density of less than 1g/cm 3;
• wherein said outer shell is capable of maintaining a vacuum in the substantially hollow inner space when said outer shell is sealed;
• wherein the fluid is at least one of a gas, a vapor, a liquid and a combination thereof;
• and
• wherein said substantially hollow inner space consisting of vacuum.