記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Advanced Science  

Understanding the molecular structures that exhibit ferroelectric liquid crystal (FLC) phases during both heating and cooling processes, i.e., enantiotropic FLC phases, remains a significant challenge. In this study, nine analogs based on a fluorinated phenyl 4-biphenylcarboxylate backbone are designed, and their FLC properties are evaluated. Of these, eight analogs exhibit enantiotropic FLC phases. One analog containing the 2-fluorobenzoate unit and a cyano terminal exhibits an enantiotropic ferroelectric nematic (N<inf>F</inf>) phase at 119°C–190°C. In contrast, analogs incorporating a 2,6-difluorobenzoate unit show weakened or absent ferroelectric properties, whereas the introduction of a cyano terminal group leads to the emergence of an enantiotropic N<inf>F</inf> phase. Quantum chemical calculations suggest that the planar orientation of the 2-fluorobenzoate unit effectively promotes intermolecular interactions in parallel arrangements rather than antiparallel ones, thereby stabilizing FLC phases. Furthermore, an analog containing an asymmetrically fluorinated 4-biphenylcarboxylate backbone exhibits an enantiotropic ferroelectric smectic A (SmA<inf>F</inf>) phase at 92°C–124°C. These results provide strong evidence that structural motifs comprising fluorinated biphenyl and planar benzoate skeletons are effective in promoting enantiotropic FLC phases. This study highlights the critical role of the mesogenic core structure (backbone) and provides valuable insights for the molecular design of enantiotropic FLC materials.

DOI： 10.1002/advs.75740

Web of Science

Scopus

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physical Chemistry C  

Strong metal–support interaction (SMSI) represents a fundamental phenomenon in heterogeneous catalysis, significantly influencing activity, selectivity, and stability. Traditionally, SMSI has been characterized only at its final state, overlooking the transient evolution of interfacial processes. In this study, we provide a direct visualization of interfacial SMSI dynamics under repeated rapid redox cycles using modulation-excitation X-ray absorption spectroscopy (ME-XAS), providing real-time insights into structural and electronic transformations at the metal–support interface. Our findings systematically reveal how critical factors governing SMSI (metal loading, gas atmosphere, and temperature) induce distinct spectral changes at the Pt L<inf>III</inf>- and Ti K-edges. Complete and reversible encapsulation occurred under rapid reductive treatment at 600 °C for the sample with the lowest Pt loading (1 wt %) and a mean particle size of 2.7 nm. Our analysis indicates that lower Pt loading enhances the reducibility of the titania support and accelerates reduction kinetics. The ME methodology revealed the relative rates of the SMSI encapsulation process, confirming a sequential mechanism: initial TiO<inf>2</inf> reduction, subsequent Pt surface reduction, and eventual formation of Pt–Ti interfacial bonds. This comprehensive understanding of SMSI dynamics offers new insights for designing robust and efficient catalysts for industrial applications.

DOI： 10.1021/acs.jpcc.6c01787

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Macromolecular Materials and Engineering  

Liquid crystal/polymer composites, the so-called polymer-dispersed liquid crystals (PDLCs), are electro-optical functional materials capable of switching between light-transmitting and light-scattering states upon the application of an electric field on and off, respectively. They are widely used in applications such as smart windows, which can change their transparency in response to an applied voltage. In the electric field-off process, the decay of transmittance in PDLC is caused by the relaxation of liquid crystal molecules to their initial orientation, and the decay response time is generally dependent on the material properties, such as the elastic constant and viscosity of the liquid crystal material. Faster response times are highly desirable for applications in optical modulation devices. In this study, we fabricated PDLCs using a liquid crystal mixture composed of ferroelectric nematic liquid crystal, DIO with spontaneous polarization, and a structurally related compound. The electro-optical response behavior of the PDLCs exhibited an ultra-fast decay response of 0.13 ms when the electric field is switched off, which is 1/100 that of conventional PDLCs using standard liquid-crystal materials. This ultrafast response was attributed to the electrostatic repulsions among liquid crystal domains induced by the spontaneous polarization of the ferroelectric nematic liquid crystals.

DOI： 10.1002/mame.202500369

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsanm.5c03680

掲載種別：研究論文（学術雑誌）  

DOI： 10.3762/bjoc.20.7

担当区分：筆頭著者