Main chain liquid crystal elastomer's (MCLCE) are composed of end to end linked LC mesogens that form a linaer LC polymer chain. The LC polymers are cross-linked to each other to form the MCLCE. This differs from side chain LCE (SCLCE) which utilize a linear siloxane polymer. The structure of a MCLCE is shown in the picture to the left, where the mesogens are represented by grey cylinders, polymer chain to chain cross-links by black dots, and links between mesogens by short wavy lines. This type of connectivity allows MCLCE to undergo a dramatic changes in dimension, approaching 500%.
The photograph below illustrates the contraction of an LCE as it is heated to the isotropic phase transition. The materials may be prepared by spin casting method using either chemical or photo-crosslinking methods to establish the polymer network. (ref. Macromolecules 2008, (41) p 3098
Andrija Lebar & Felicity Brömmel provided instruction for preparation of chemically & photo-crosslinked MCLCE

This material may be prepared either by spin casting or photo-crosslinked in a cell. When made in a cell, the glass is coated with a sacrificial layer and is photo-crosslinked. When spin cast, the material is made using a chemical crosslinker.

  1. Chemical synthesis
  2. Mixture preparation
  3. Cell loading or spin casting
  4. Release from cell
  5. Characterization

Reaction progress can be monitored by UV-VIS spectroscopy, with the actual size and morphology of the Au NR checked by Transmission Electron Microscopy (TEM).

Highslide JS

The main chain LCE has three components

  1. A mesogen with 2 terminal double bonds
  2. A mesogen crosslinker molecule
  3. A polymer crosslinker molecule

The main chain nematic LCE may be prepared by spin casting, using either a chemical crosslinker or a photo-crosslinker is used.  The length of the mesogen polymer is determined by the relative concentration of monomoer crosslinker and polymer crosslinker.