Petmp

Monomers pentaerythritol tetrakis(3-mercaptopropionate) (PETMP, >95%; Darmstadt, Germany, Sigma-Aldrich), trimethylolpropane tris(3-mercaptopropionate) (TMPTMP, ≥95%; Darmstadt, Germany, Sigma-Aldrich), and trimethylolpropane triacrylate (TMPTA; Paris, France, Sartomer (Arkema Group)); surfactants polyvinylpyrrolidone K 90 (PVP K90; Darmstadt, Germany, Sigma-Aldrich), and Hypermer B246 (HB246; Snaith, UK, Croda); initiator Irgacure 784 (I784; Ludwigshafen, Germany, BASF); calcium chloride hexahydrate (CaCl₂ · 6H₂O, 98%; Darmstadt, Germany, Sigma-Aldrich); sodium hydroxide (≥98%; Darmstadt, Germany, Sigma-Aldrich); 5,5′-dithiobis(2-nitrobenzoic acid) (Ellman’s Reagent, ≥98%; Darmstadt, Germany, Sigma-Aldrich); ethanol (Milano, Italy, Carlo Erba); tetrahydrofuran (THF; Milano, Italy, Carlo Erba); N,N-diisopropylethylamine (≥99%; Darmstadt, Germany, Sigma-Aldrich); and methylene blue (MB; Darmstadt, Germany, Sigma-Aldrich) were used as received.

UHMWPE GUR 4120 with a molecular weight of 5 × 10⁶ g/mol was purchased from “Ticona GmbH.” (Hesse, Germany). Benzophenone 99% was purchased from Alfa Aesar (Shanghai, China). Micro-cellulose was purchased from “Evalar Ltd.” (Altai Krai, Russia). Pentaerythritol tetrakis (3-mercaptopropionate) > 95% (PETMP) and 1,3,5-triallyl-1,3,5-triazine-2,4,6 (1H,3H,5H)-trione—98% (TATATO) were purchased from “Sigma-Aldrich” (St. Louis, MO, USA). Polyvinyl alcohol (PVA) was purchased from “Ruskhim Ltd.” (Moscow, Russia). Medical glue based on phenol formaldehyde resin.

Stretchable CLCEs were synthesized using a combination of the thiol-acrylate chain reaction and bar-coating method. The chiral reactive mesogen (LC756, BASF) and diacrylate reactive mesogen (RM257, GRANDINCHEM) were dissolved in solvent (toluene, Sigma-Aldrich) and heated at 85 °C for 5 min. After cooling the solution to room temperature, the thiol chain extender (EDDET, Sigma-Aldrich), thiol crosslinker (PETMP, Sigma-Aldrich), photoinitiator (Irgacure 651, Sigma-Aldrich), and catalyst dipropylamine (DPA, Sigma-Aldrich) were mixed and vigorously vortexed until the appropriate viscosity for bar coating was obtained. The prepared solution was then bar-coated on the conventional OHP film using an applicator with a 220 μm gap at a speed of 11 mm s^-1. Finally, if the intended reflection color was apparent, photo-polymerization was conducted in an ultraviolet chamber for 5 min at an intensity of 30 mW cm^-2 and a central wavelength of 365 nm (CSM1010, AUVCURE). The synthesized CLCE was easily delaminated onto the OHP film using tweezers. As a result, free-standing CLCEs with a thickness of 81 μm can be fabricated.