TiO₂ nanoparticle – liquid crystal interaction with smectogenic monomers and their electropolymerised polymers

ABSTRACT

We observe the changes in the interactions of the liquid crystal (E)-6-(3-hydroxy-4-(((4-octyloxy)phenyl)imino)methyl) phenoxy)hexyl methacrylate (M6R8) with nanoparticles of TiO₂ as the concentration of the nanoparticle increases from 0 wt% to 30 wt%, both as a monomer as well as when they are electropolymerised with the nanoparticles included. The system is studied using transmission X-ray scattering, grazing incidence small angle X-ray scattering (GISAXS) and in-plane direction X-ray scattering. We have found that in addition to the monomer peak, we observe two peaks: a shoulder peak that appears close to the liquid crystal peak and a smaller peak that develops with particle concentration. These two peaks can be considered a result of nanoparticle – liquid crystal interaction. We find that as a function of the concentration the smC can be disordered or ordered, while the smA phases converge to the same order of magnitude, as shown by the convergence of the correlation length ξ. The order observed in the smA phase appears to be the same no matter the concentration used. Once electropolymerised we find no convergence in the region of the smA mesophase of the monomer.

Graphical abstract

KEYWORDS:

• Nanoparticles
• methacrylic LC monomers
• electropolymerisation
• grazing incidence X-ray scattering
• nanoparticle interactions

Acknowledgments

P. Romero Hasler and A. Meneses-Franco acknowledge CONICYT scholarships 21130413 and 21090713, respectively, for doctoral studies. E. A. Soto-Bustamante thanks FONDECYT Project 1130187 and 1171595. L. J. Martínez-Miranda thanks partial support by a Fulbright Scholarship, supported by the Institute of International Education/Council for International Exchange of Scholars and by the Comisión para el Intercambio Educativo entre Chile y los Estados Unidos de América.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Comisión Nacional de Investigación Científica y Tecnológica [21090713,21130413]; Fondo Nacional de Desarrollo Científico y Tecnológico [1130187,1171595]; Fulbright Association.