Technology Summary

Regular polymers use two functional groups (a head and a tail) to connect monomers (polymer pieces) into polymers (long chains of monomers).  The head bites the tail of the next monomer to form the chain. 

NSI's monomers use four functional groups (a head, tail, arm and leg). The head starts out biting the tail of the next monomer (step 1).  But then the leg reaches backward to stabilize the head-tail linkage behind it (step 2), and the arm reaches forward to stabilize the tail-head linkage in front of it (step 3).  This "freezes" each polymer linkage into a specific conformation (a molecular posture).  This gives NSI's polymers a nanostructured backbone.  The backbones of regular polymers are limp.

Each monomer has an inherent vector (size and directionality) associated with it.  There are left-turning monomers, straight (no-turning) monomers, right-turning monomers.  There are sharp-turning and gentle-curving monomers.   And there are inverting monomers (monomers which switch the directionality of subsequent monomers).  So a right-right-right-right sequence will spiral into a nanocoil.  A right-straight-right-straight sequence will create a nanocoil of a bigger diameter.  A right-left-right-left sequence produces a sinusoidal or "sawtooth" polymer.  Then there are more complicated sequences that can make more sophisticated structures.

With a structured backbone, the chemical groups attached to the backbone become structured.   These attached "functional groups" can have positional precision and orientational precision.  Both positional precision and orientational precision are designed into the sulfonyl functional groups of our first products, a family of non-hopping battery electrolytes custom built for different cations.  

Combinations of functional groups can deliver highly specific functionalities.  Two such functions are combined to create di-lithium pockets only on the inside surface of a hollow polymer coil.  Our intended goal, eliminate the swelling and contraction of lithium anodes during charging and discharging to avoid cracking brittle battery structures (e.g., the solid-electrolyte interface).  We also expect that this atomic-precision construct will lessen or prevent lithium-metal dendrite formation during charging.  Lithium-metal batteries have twice the energy capacity of lithium-ion battteries. 

Notes and Elaborations

For a bigger image and a bit more description of the arm-and-leg illustration, click here.

For a multi-page, broad-context, in depth technology review, go to the Technology page.

Vector polymers refers to polymers with inherent directionality.  Regular polymers have loose linkages that are free to hinge, rotate and pivot.  So they have no inherent vector.  If a vector is needed in a non-vector polymer, it must be imposed by top-down techniques.  This is what Honeywell does with polyethylene to produce Spectra-brand polyethylene.  Spectra nautical rope is stronger than Kevlar and floats on water.  This is just the tip of the iceberg of the kinds of performance value that can be enabled by fully nanostructured materials

Vector-directional polymer linkages are typically "frozen" with a combination of covalent bonds, hydrogen bonds and lithium bonds.  Covalent bonds are very strong and are represented by solid lines in chemical drawings.  Hydrogen bonds and lithium bonds are comparatively weak and are represented by dashed lines (see the arm and leg portions of the linkage in the illustration).  This composite bonding scheme allows the linkage nanostructure to be temporarily disrupted by mechanical and impact forces which are strong enough to break hydrogen bonds but not strong enough to break the covalent bonds of the polymer backbone.  The energy of the disruption/impact is absorbed into the broken hydrogen bonds (and material deformation), and upon dissipation of the energy, the hydrogen bonds reform, providing an inherent self-repair capability to these polymers.

For many applications, positional precision of pendant groups may be entirely sufficient for optimal functionality.  This is probably the case for ion conductivity.  However, there are potential applications where orientational precision is critical, as might be expected for optical and other electromagnetic-interactive materials (see Applications for the included example of negative-refraction-index metamaterials).