Tailoring material composition for optimization of application-specific switchable holograms

A polymer-dispersed liquid crystal material for forming a polymer-dispersed liquid crystal optical element comprising:

• a first polymerizable monomer and a second polymerizable monomer;
• at least one type of liquid crystal material;
• a photoinitiator dye;
• a co-initiator;
• and
• a reactive di lent;
• wherein the first polymerizable monomer and the second polymerizable monomer are polymerized according to different chemical processes.

A switchable optical element having an improved contrast ratio comprising:

• a polymer matrix having a first index of refraction;
• a liquid crystal having a second index of refraction;
• and
• an alkyl chain additive, wherein the alkyl chain additive modifies the second index of refraction so that upon application of a voltage to the switchable optical element the first index of refraction is matched with the second index of refraction and produces minimum diffraction efficiency within the switchable optical element.

A method for increasing the operating temperature of a switchable optical element comprising:

• adding a diluent to a polymer-dispersed liquid crystal material;
• exposing the polymer-dispersed liquid crystal material to white light for a predetermined amount of time;
• and
• exposing the polymer-dispersed liquid crystal material to a heat cycle.

A polymer-dispersed liquid crystal material for forming a switchable polymer-dispersed liquid crystal optical element comprising:

• at least one polymerizable monomer,
• at least one type of liquid crystal material;
• a photoinitiator dye;
• a reactive diluent;
• and
• an additive monomer acrylate with branched alkyl chains, wherein the additive monomer acrylate reduces the switching voltage of the polymer-dispersed liquid crystal optical element.

A polymer-dispersed liquid crystal material for forming a polymer-dispersed liquid crystal optical element comprising:

• at least one acrylic acid monomer;
• at least one type of liquid crystal material;
• a photoinitiator dye;
• a co-initiator;
• a surfactant;
• wherein a polymer matrix is formed upon polymerization of the polymer-dispersed liquid crystal material containing the at least one acrylic acid monomer in an amount sufficient it to increase the conductivity of the polymer matrix and cause a reduction in the switching voltage;
• and
• further wherein the at least one acrylic acid monomer is approximately 1.0–1.5 percent of the weight of the polymer-dispersed liquid crystal material.

A polymer-dispersed liquid crystal material for forming a polymer-dispersed liquid crystal optical element comprising:

• at least one acrylic acid monomer;
• at least one type of liquid crystal material;
• a photoinitiator dye;
• at co-initiator,
• a surfactant;
• wherein a polymer matrix is formed upon polymerization of the polymer-dispersed liquid crystal material containing the at least one acrylic acid monomer in an amount sufficient to increase the conductivity of the polymer matrix and cause a reduction in the switching voltage;
• and
• further wherein the acrylic acid monomer is replaced by at least one of the following selected from the group consisting of:
• a reactive ionic material, an aromatic material, a polypyrrole, and an acrylated or methacrylated acid of the type H2CCH—(CO)O—R—(CO)OH, where R is a linear or branched alkyl chain.