Two polymer network conformations currently exist for LCE materials: Side chain LCE (SCLCE)& Main chain LCE (MCLCE) illustrated below. The side chain conformation has the LC mesogen pendant from the linear polymer network. The main chain LCE has the LC mesogens linked end to end forming a LC polymer which is cross-linked to form the network. Either nematic or smectic LCE may be prepared from side chain and main chain LCE

Cartoon representation of preparation of a LCE via polymerization of using acrylate mesogens (blue) and cross-linker molecules (dark orange). The LHS of the image shows a homogeneous mixture of mesogen and cross-linker, while the RHS image shows the ordered polymer network. The mixture is loaded into a cell above the clearing temperature in the isotropic phase. Afterward, it is cooled below the clearing temperature to the liquid crystalline phase, and exposed to light to start the photo-initiation process. The LCE material is then released from the cell for a free standing film.

Side chain LCE prepared through photo-polymerization of acrylate mesogens. Please click on the image to enlarge for a detailed explanation. Materials available from the facility of this type include photo-sensitive polymer networks (Ikeda) and vapor sensitive LCE (Broer).

Cartoon representation of preparation of a side chain LCE via hydrosilylation reaction between a linear siloxane polymer (green), mesogen (blue) and cross-linker (orange). The LHS of the image shows a homogeneous mixture of mesogen and cross-linker, while the RHS image shows the ordered polymer network. Notice the siloxane polymer has changed from globule to an extended polymer. This material can be prepared in either a cell or by spin casting.

Side chain LCE prepared via hydrosilylation reaction of vinyl mesogen with methyl-hydrosiloxane polymer. Materials of this type available from the facility include LCE films developed by either H. Finkelmann's group or R. Zentel's group. Please click on image to expand for more detailed information.

Cartoon representation of preparation of a main chain LCE via hydrosilylation reaction between a linear siloxane linker molecules with two reactive sites(blue), mesogen (red) and cross-linker with four reactive sites (green). The LHS of the image shows a homogeneous mixture of mesogen and two types of linker molecules, while the RHS image shows the ordered polymer network. Notice that the mesogen has two reactive sites, one on each end of the molecule. By linking the mesogens end to end using the small blue siloxane linker, a LC polymer is made. Simultaneously, the polymer network reacts with the circular cross-linker with either 4 or 5 reactive sites, depending on the cross-linker molecules used to connect LC polymers with each other forming the LCE network shown on the right.

Main chain LCE prepared via hydrosilylation reaction of vinyl mesogen with methyl-hydrosiloxane polymer. Materials of this type available from the facility were developed at H. Finkelmann's research lab. Please click on image to expand.