Synthesis of photoresponsive liquid crystal elastomers: A general chemical approach

Guillen Campos, Jesus1; Park, Minwook1; Wu, Yuhang1; Sandlass, Sara1; Novikov, Egor2; Bailey, Sophia1; Gordon, Michael1; Timofeeva, Tatiana2; Read de Alaniz, Javier 1

Published May 13, 2025 on Dryad. https://doi.org/10.5061/dryad.tqjq2bw8z

Data files

May 13, 2025 version files 4.66 MB

README.md

29.92 KB
Text_files.zip

4.63 MB

Abstract

Liquid crystal elastomers represent a versatile class of polymer materials with potential applications in soft robotics, adhesives, and smart materials. The integration of photoresponsive molecules into LCEs enables spatiotemporal control, wavelength-selective actuation and remote operations, expanding their application space. However, the incorporation of sensitive photoresponsive molecules is often hindered by the chemical methods and processing conditions required for the LCE fabrication. In this work, we introduce a general strategy for covalent incorporation of photoresponsive moieties into LCEs through Diels–Alder chemistry, utilizing late-stage functionalization. This approach facilitates the retention of material alignment and thermomechanical properties, while enabling the functionalization of thick, aligned polysiloxane elastomers. A wide range of photoresponsive molecules, including azobenzenes, spiropyrans, cyanine dyes, and donor-acceptor Stenhouse adducts, were successfully integrated, demonstrating this method’s versatility. Furthermore, we leverage the reversible nature of Diels–Alder conjugation to achieve on-demand editing and exchange of photoresponsive moieties within a single LCE, allowing for dynamic tuning of material properties. This platform offers a scalable and efficient route for developing multifunctional LCEs, providing new opportunities for advanced stimuli-responsive materials and broadening the scope of applications across various fields.

https://doi.org/10.5061/dryad.tqjq2bw8z

Description of the data and file structure

Data from peer-reviewed article:

Title: Synthesis of Photoresponsive Liquid Crystal Elastomers: A General Chemical Approach

Authors: Jesus Guillen Campos, Minwook Park, Yuhang Wu, Sara Sandlass, Egor Novikov, Sophia Bailey, Michael Gordon, Tatiana Timofeeva and Javier Read de Alaniz

Corresponding author: Javier Read de Alaniz, javier@chem.ucsb.edu

-----------------------------------------------------------------------------------------------------------------

Files and variables

File: Text_files.zip

File List

1)Figure 2B

2)Figure 2C

3)Figure 4A

4)Figure 4B

5)Figure 4C

6)Figure 4D

7)Figure 6C

8)Figure 6D

9)Figure S1

10)Figure S4

11)Figure S5

12)Figure S7

13)Figure S8

14)Figure S9

15)Figure S10

16)Figure S11

17)Figure S12

18)Figure S13

19)Figure S14

20)Figure S15

21)Figure S16

22)Figure S17

23)Figure S18

24)Figure S19

25)Figure S20

26)Figure S21

27)Figure S22

28)Figure S23

29)Figure S24

30)Figure S25

31)Figure S26

32)Figure S32

33)Figure S33

34)Figure S34

35)Figure S35

36)Figure S36

37)Figure S37

38)Figure S38

39)Figure S39

40)Figure S40

41)Figure S41

42)Figure S42

43)Figure S43

44)Figure S44

45)Figure S45

46)Figure S46

47)Figure S47

48)Figure S48

49)Figure S49

50)Figure S50

51)Figure S51

52)Figure S72

53)Figure S73

54)Figure S74

55)Figure S75

56)Figure S76

57)Figure S77

58)Figure S78

59)Figure S79

60)Figure S80

61)Figure S81

62)Figure S82

63)Figure S83

64)Figure S84

65)Figure S102

66)Figure S103

67)Figure S104

68)Figure S105

69)Figure S106

70)Figure S107

71)Figure S108

72)Figure S109

73)Figure S110

74)Figure S111

-----------------------------------------------------------------------------------------------------------------------

1)Figure 2B

1H NMR traces of the hydrosilylation reaction of the furan handle with PHMS from 0 to 60 minutes where consumption of the terminal vinyl group is monitored while the integration of furan aromatic hydrogens remains constant.

row 1: Chemical shift (ppm)

row 2: Spectrum after 0 min (a. u.)

row 3: Spectrum after 5 min (a. u.)	

row 4: Spectrum after 30 min (a. u.)	

row 5: Spectrum after 60 min (a. u.)

The previous results were extracted from the integrations using the Mestrenova integration function over the indicated area in the manuscript and the total set of raw HNMR data can be found in the corresponding data attached to figure S1.

-----------------------------------------------------------------------------------------------------------------------

2)Figure 2C

Plot of the conversion of the hydrosilylation reaction.

row 1: Time (min)

row 2: Furan1 (% conversion)

row 3: Vinilgemhidrogen	(% conversion)

row 4: formation (% conversion)

-----------------------------------------------------------------------------------------------------------------------

3)Figure 4A

Plot of the effect of the PRM loading in the LCE in the glass transition temperature as recorded by DSC at a heating rate of 10 °C per minute.

row 1: Furan loading (wt. %)

row 2: Glass transition temperature Furan LCE (Degree Celsius)

row 3: Glass transition temperature Red dye (Degree Celsius)

row 4: Glass transition temperature Azobenzene (Degree Celsius)

row 5: Glass transition temperature Spiropyran (Degree Celsius)

row 6: Glass transition temperature DASA (Degree Celsius)

row 7: Glass transition temperature Blue dye (Degree Celsius)

The previous results were extracted from the mid-point of the second order phase transition seen in the calorigram between -20 and 20 degrees Celsius. Such raw data corresponding to the full temperature scan can be found in the file of Figure S4, Figure s24, Figure S25 and Figure S26

-----------------------------------------------------------------------------------------------------------------------

4)Figure 4B

Effect of the loading of the PRM in the nematic to isotropic temperature obtained by DSC.

row 1: Furan loading (wt. %)

row 2: Nematic to isotropic temperature Furan LCE (Degree Celsius)

row 3: Nematic to isotropic temperature Red dye (Degree Celsius)

row 4: Nematic to isotropic temperature Azobenzene (Degree Celsius)

row 5: Nematic to isotropic temperature Spiropyran (Degree Celsius)

row 6: Nematic to isotropic temperature DASA (Degree Celsius)

row 7: Nematic to isotropic temperature Blue dye (Degree Celsius)

The previous results were extracted from the local minima of the pseudo first order phase transition seen in the calorigram between 20 and 100 degrees Celsius. Such raw data corresponding to the full temperature scan can be found in the file of Figure S4, Figure s24, Figure S25 and Figure S26

-----------------------------------------------------------------------------------------------------------------------

5)Figure 4C

Order parameter as a function of the introduced PRM determined by 2D WAXD.

row 1: Furan loading (wt. %)

row 2: Order parameter Furan LCE (unitless)

row 3: Order parameter Red dye (unitless)

row 4: Order parameter Azobenzene (unitless)

row 5: Order parameter Spiropyran (unitless)

row 6: Order parameter DASA (unitless)

row 7: Order parameter Blue dye (unitless)

The previous results were extracted from the half-with of the plots of intensity as a function of the azimuthal angle using the equation S(order parameter)=|(half width-180)/180|. Such raw data corresponding to the full azimuthal angle scan can be found in the file of Figure S32 to Figure S51.

-----------------------------------------------------------------------------------------------------------------------

6)Figure 4D

Linear dichroism of the introduced PRMs in the siloxane LCEs determined by polarized UV-Vis spectroscopy.

row 1: photoresponsive molecule (na)

row 2: parallel absorbance (a. u.)

row 3: perpendicular absorbance (a. u.)

row 4: dichroic value (unitless)

The previous results were extracted from the linear absorbance as a function of film tilt angle. Such data can be found in the files provided from Figure S75 to Figure S79.

-----------------------------------------------------------------------------------------------------------------------

7)Figure 6C

Solid-state absorbance trace of the disperse red dye LCE before editing.

row 1: Wavelength (nm)

row 2: Absorbance (a. u.)

-----------------------------------------------------------------------------------------------------------------------

8)Figure 6D

Solid-state absorbance trace of the edited DASA LCE.

row 1: Wavelength (nm)

row 2: Absorbance (a. u.)

-----------------------------------------------------------------------------------------------------------------------

9)Figure S1

CDCl3 1H NMR trace of the reaction of linear PHMS with the furan handle in the presence of platinum catalyst at 70 °C in CDCl3toluene.

row 1: Chemical shift (ppm)	

row 2: Spectrum after 0 min (a. u.)	

row 3: Spectrum after 5 min (a. u.)

row 4: Spectrum after 10 min (a. u.)

row 5: Spectrum after 30 min (a. u.)

row 6: Spectrum after 40 min (a. u.)

row 7: Spectrum after 20 min (a. u.)

row 8: Spectrum after 60 min (a. u.)

-----------------------------------------------------------------------------------------------------------------------

10)Figure S4

Differential Scanning Calorimetry of furan functionalized LCEs at different furan loadings.

row 1: Temperature Finkelmann (Degree Celsius)

row 2: Heat flow Finkelmann (W/g)

row 3: Temperature Furan Handle 1 % (Degree Celsius)

row 4: Heat flow Furan Handle  1 % (W/g)

row 5: Temperature Furan Handle 5 % (Degree Celsius)

row 6: Heat flow Furan Handle  5 % (W/g)

row 7: Temperature Furan Handle 10 % (Degree Celsius)

row 8: Heat flow Furan Handle  10 % (W/g)

-----------------------------------------------------------------------------------------------------------------------

11)Figure S5

Nematic to isotropic and glass transition temperatures as a function of the added furan handle.

row 1: Furan loading (wt. %)

row 2: Glass transition temperature (Degree Celsius)

row 3: Nematic to isotropic temperature (Degree Celsius)

-----------------------------------------------------------------------------------------------------------------------

12)Figure S7

Change in the order parameter as a function of added furan handle determined by 2D WAXD.

row 1: Furan loading (wt. %)

row 2: Order parameter (unitless)

-----------------------------------------------------------------------------------------------------------------------

13)Figure S8

2D WAXD of the Finkelmann films before and after high vacuum for three days.

row 1: Azimuthal angle of the film before drying (Degrees)

row 2: Intensity of the film before drying (a. u.)

row 2: Azimuthal angle of the film after drying (Degrees)

row 4: Intensity of the film before drying (a. u.)

-----------------------------------------------------------------------------------------------------------------------

14)Figure S9

Normalized UV-Visible spectrum of DASA-maleimide in THF.

row 1: Wavelength (nm)

row 2: Absorbance (a. u.)

-----------------------------------------------------------------------------------------------------------------------

15)Figure S10

Normalized UV-Visible spectrum of blue dye-maleimide in THF.

row 1: Wavelength (nm)

row 2: Absorbance (a. u.)

-----------------------------------------------------------------------------------------------------------------------

16)Figure S11

Normalized UV-Visible spectrum of azobenzene-maleimide in THF.

row 1: Wavelength (nm)

row 2: Absorbance (a. u.)

-----------------------------------------------------------------------------------------------------------------------

17)Figure S12

Normalized UV-Visible spectrum of disperse red dye-maleimide in THF.

row 1: Wavelength (nm)

row 2: Absorbance (a. u.)

-----------------------------------------------------------------------------------------------------------------------

18)Figure S13

Normalized UV-Visible spectrum of spiropyran-maleimide in THF.

row 1: Wavelength (nm)

row 2: Absorbance (a. u.)

-----------------------------------------------------------------------------------------------------------------------

19)Figure S14

Spectroscopic calibration curve of DASA-maleimide at 640 nm in THF.

row 1: Concentration (M)

row 2: Absorbance at 640 nm (a. u.)

-----------------------------------------------------------------------------------------------------------------------

20)Figure S15

Spectroscopic calibration curve of blue dye-maleimide at 655 nm in THF.

row 1: Concentration (M)

row 2: Absorbance at 655 nm (a. u.)

-----------------------------------------------------------------------------------------------------------------------

21)Figure S16

Spectroscopic calibration curve of azobenzene-maleimide at 350 nm in THF.

row 1: Concentration (M)

row 2: Absorbance at 350 nm (a. u.)

-----------------------------------------------------------------------------------------------------------------------

22)Figure S17

Spectroscopic calibration curve of disperse red dye-maleimide at 475 nm in THF.

row 1: Concentration (M)

row 2: Absorbance at 475 nm (a. u.)

-----------------------------------------------------------------------------------------------------------------------

23)Figure S18

Spectroscopic calibration curve of spiropyran-maleimide at 340 nm in THF.

row 1: Concentration (M)

row 2: Absorbance at 340 nm (a. u.)

-----------------------------------------------------------------------------------------------------------------------

24)Figure S19

Absorbance of azobenzene-functionalized LCE (0.5 wt. %) in the solid state.

row 1: Wavelength (nm)

row 2: absorbance (a. u.)

-----------------------------------------------------------------------------------------------------------------------

25)Figure S20

Absorbance of disperse red dye-functionalized LCE (0.5 wt. %) in the solid state.

row 1: Wavelength (nm)

row 2: absorbance (a. u.)

-----------------------------------------------------------------------------------------------------------------------

26)Figure S21

Absorbance of spiropyran-functionalized LCE (0.5 wt. %) in the solid state.

row 1: Wavelength (nm)

row 2: absorbance (a. u.)

-----------------------------------------------------------------------------------------------------------------------

27)Figure S22

Absorbance of blue dye-functionalized LCE (0.5 wt. %) in the solid state.

row 1: Wavelength (nm)

row 2: absorbance (a. u.)

-----------------------------------------------------------------------------------------------------------------------

28)Figure S23

Absorbance of DASA-functionalized LCE (0.5 wt. %) in the solid state.

row 1: Wavelength (nm)

row 2: absorbance (a. u.)

-----------------------------------------------------------------------------------------------------------------------

29)Figure S24

Differential Scanning Calorimetry of photoswitch functionalized LCEs at 1 wt. % furan loading.

row 1: Temperature Azobenzene 1 wt %	

row 2: Heat flow Azobenzene 1 wt %	

row 3: Temperature Red dye 1 wt %	

row 4: Heat flow Red dye 1 wt %	

row 5: Temperature Spiropyran 1 wt %	

row 6: Heat flow Spiropyran 1 wt. %	

row 7: Temperature Blue dye 1 wt. %	

row 8: Heat flow Blue dye 1 wt. %	

row 9: Temperature DASA 1 wt. %	

row 10: Heat flow DASA 1 wt. %

-----------------------------------------------------------------------------------------------------------------------

30)Figure S25

Differential Scanning Calorimetry of photoswitch functionalized LCEs at 5 wt. % furan loading.

row 1: Temperature Azobenzene 5 wt %	

row 2: Heat flow Azobenzene 5 wt %	

row 3: Temperature Red dye 5 wt %	

row 4: Heat flow Red dye 5 wt %	

row 5: Temperature Spiropyran 5 wt %	

row 6: Heat flow Spiropyran 5 wt. %	

row 7: Temperature Blue dye 5 wt. %	

row 8: Heat flow Blue dye 5 wt. %	

row 9: Temperature DASA 5 wt. %	

row 10: Heat flow DASA 5 wt. %

-----------------------------------------------------------------------------------------------------------------------

31)Figure S26

Differential Scanning Calorimetry of photoswitch functionalized LCEs at 10 wt. % furan loading.

row 1: Temperature Azobenzene 10 wt %	

row 2: Heat flow Azobenzene 10 wt %	

row 3: Temperature Red dye 10 wt %	

row 4: Heat flow Red dye 10 wt %	

row 5: Temperature Spiropyran 10 wt %	

row 6: Heat flow Spiropyran 10 wt. %	

row 7: Temperature Blue dye 10 wt. %	

row 8: Heat flow Blue dye 10 wt. %	

row 9: Temperature DASA 10 wt. %	

row 10: Heat flow DASA 10 wt. %

-----------------------------------------------------------------------------------------------------------------------

32)Figure S32

Intensity as a function of the azimuthal angle of the wide-angle X-ray scattering of 0.5 wt. % furan in the LCE.