We refer to processes that transmit information using chemical (fluidic and optical) strategies, without electricity, as chemical communication. Such processes are a component of the broader subject of “infochemistry”- the intersection of chemistry, materials science, and information technology. Examples of chemical communication that we are currently exploring include infofuses, droplet shutters, droplet lasers, and oscillating flames. The transfer of information requires (at least) three major steps: generation, transmission, and detection. The vast majority of communication technologies use electromagnetic radiation and/or electrical potential, with photons or electrons as the working fluid. Biological systems communicate messages using chemicals (for example, mRNA for transmission of information from the DNA to the ribosome), and chemicals are integral to a wide range of analog communication systems using hormones, pheromones, and other signaling molecules. Infochemical strategies for communicating information have five characteristics that differentiate them from existing methods of communication: i) They can function even when electricity is not accessible or is only available in limited supply. ii) They release energy from chemical reactions (i.e., combustion of hydrocarbons) with 10-100x higher volumetric energy densities than do batteries. iii) They can encode information using orthogonal chemical and physical properties (e.g., intensity, wavelength, polarization of light). iv) They can integrate chemical sensing with transmission of information about their environment. v) They can operate in environments where electronic systems might fail (e.g., underwater, inside the body, in strong electromagnetic fields).
The objective of this research is to develop a system that transmits information from a sender to a receiver in the form of coded pulses of light generated entirely by chemical reactions; electronics are not a part of transmission. It is the first step toward systems that integrate the transmission of alphanumeric information (usually accomplished by using electronic or photonic systems) and sensing/transducing (often accomplished by using chemistry). This system encodes the information as a spatial pattern of metallic salts on a string of flammable polymer (a ‘‘fuse’’); this fuse emits pulses of light in the visible or infrared spectrum when it burns. This research lies at a new interface in science between information technology and chemistry; we call this area ‘‘infochemistry,’’ and the specific type of transmitter of information described here, an ‘‘infofuse.’’
(1) Thomas, S. W. et al. Proc. Nat. Acad. Sci. 2009, 106, 9147-9150.
(2) Kim, C.; Thomas, S. W.; Whitesides, G. M. Angew. Chem. Int. Ed. 2010, 49, 4571-4575.