Multifunctional balloon membrane

Abstract

Disclosed herein is system comprising a lighter-than-air (LTA) device and method of making the same. In an embodiment, the system includes the LTA device, which includes a membrane having a flexible substrate and an active material disposed thereon, wherein the active material is configured to controllably change the surface area of at least a portion of the substrate when an electrical stimulus is applied to the active material. In addition, the system may include a payload box; an altitude control vent mechanism; a meteorological data collection package; a communication unit; and an antenna.

What is claimed is: 
     
         1 . A lighter-than-air (LTA) device, comprising:
 an outer enclosure which encloses a space filled with air; and   an active surface enclosure which encloses a lighter-than-air (LTA) gas comprising, an outer graphene membrane, an elastomer membrane and an inner graphene membrane;   wherein the lighter-than-air (LTA) device is operable to work as an altitude control device.   
     
     
         2 . The lighter-than-air (LTA) device of  claim 1 , wherein the active surface enclosure is inside the outer enclosure. 
     
     
         3 . The lighter-than-air (LTA) device of  claim 1 , wherein the lighter-than-air (LTA) gas used comprises helium or hydrogen. 
     
     
         4 . The lighter-than-air (LTA) device of  claim 1 , wherein a high voltage is applied to the outer graphene membrane and the inner graphene membrane, an electric field is formed across elastomer E, thereby increasing surface area of the outer graphene membrane and the inner graphene membrane allowing the LTA gas to expand, thereby decreasing average density of the LTA device and increasing its buoyancy, allowing it to ascend. 
     
     
         5 . The lighter-than-air (LTA) device of  claim 1 , wherein removal of voltage results in the outer graphene membrane and the inner graphene membrane to return to their original size, compress the LTA gas and increases average density of the LTA device, decreasing its buoyancy and allowing the LTA to descend. 
     
     
         6 . The lighter-than-air (LTA) device of  claim 1 , wherein increase or decrease in volume of active surface enclosure is controlled by controlling applied voltage. 
     
     
         7 . The lighter-than-air (LTA) device of  claim 1 , wherein the outer enclosure may be formed using a plurality of layers. 
     
     
         8 . The lighter-than-air (LTA) device of  claim 7 , wherein the plurality of layers of the outer enclosure comprises of a first (outermost) layer formed from a suitable structural material as polyethylene (PE) or PET, a second layer forming a flexible photovoltaic cell, a third layer that forms a battery for storing energy generated by the second layer forming the flexible photovoltaic cell, and a fourth layer formed from another suitable structural material and has printed thereon, electronic components as antennae and connecting wires. 
     
     
         9 . The lighter-than-air (LTA) device of  claim 8 , wherein the flexible photovoltaic cell may include, for example, poly [2 methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) forming p-type material; phenylC61-butyric acid methyl ester (PCBM) forming n-type material of PV diode; ITO forming cathode; and aluminum forming anode material. 
     
     
         10 . The lighter-than-air (LTA) device of  claim 7 , wherein the outer enclosure may be colored in at least two colors, wherein a first color applied to a first portion of the outer enclosure and a second color applied to a second portion of the outer enclosure wherein the first color and the second color may be chosen to have different heat absorption coefficients. 
     
     
         11 . A method of preparing a lighter-than-air (LTA) gas enclosure with an active surface, comprising:
 stretching a flexible material along its surface on a first axis and a second axis to prepare a pre-stretched substrate surface;   disposing of a graphene sheet on each side of the pre-stretched substrate surface such that an elastomer is sandwiched between the graphene sheet on each side; and   allowing the pre-stretched substrate surface to relax.   
     
     
         12 . The method of  claim 11 , wherein the lighter-than-air (LTA) gas enclosure is made from the flexible material comprising latex rubber, silicone or other suitable elastomers. 
     
     
         13 . The method of  claim 11 , wherein the flexible material is stretched along the first axis and the second axis symmetrically or asymmetrically. 
     
     
         14 . The method of  claim 11 , wherein the graphene sheet is disposed on entire of the pre-stretched substrate surface or at least on a portion of the pre-stretched substrate surface. 
     
     
         15 . The method of  claim 11 , wherein the graphene sheet disposing process on each side of the pre-stretched substrate surface, comprises:
 growing of graphene film on a nickel film on a silicon wafer using chemical vapor deposition;   adhering a polydimethyl siloxane (PDMS) stamp to the graphene film on the silicon wafer;   detaching the graphene film with the PDMS stamp from the silicon wafer by etching off the nickel film using, e.g., a FeCl3 solution;   rinsing the graphene film or PDMS sample by, e.g., isopropanol and deionized water;   drying the graphene film or PDMS sample in, e.g., air or nitrogen gas;   stamping the graphene film or PDMS on a biaxially stretched elastomer film, e.g., VHB acrylic film, to transfer the graphene film to the elastomer film; and   relaxing pre-strains in the elastomer film sequentially along two pre-stretch axes of the biaxially stretched elastomer film.