Structural phase transitions in langmuir liquid crystal films

Lock and Key Adsorption Chemistry: Preferential Absorption of an Isomer of Di-iodobenzene on Molecular Films of Quinonoid Zwitterions

“…It is, however, 1,3-disubstituted benzene that shares the same symmetry as the C 6 core of the zwitterion substrate molecules. While molecular dipoles certainly have a profound influence on adsorption, − ,− here we show that dipolar interactions alone cannot explain the preferential adsorption of one isomer of di-iodobenzene. The oxygen and nitrogen functional groups of this class of p -benzoquinonemonoimine zwitterions should also play a role, as potentially influencing the chemoselective adsorption chemistry of a “guest” molecule from the vapor. ,, …”

“…Molecules possessing a strong intrinsic dipole can be used for testing if electrostatic dipolar interactions can lead to preferential adsorption on electrostatically biased substrates. − Both the magnitude of the molecular electrostatic dipole and the frontier orbital symmetry play a dominant role in the adsorption process. Even when intermolecular interactions do not involve any irreversible chemical reaction between the molecular species, there is a balance between the chemical interactions and the electrostatic dipolar interactions. ,,− …”

“…Even when intermolecular interactions do not involve any irreversible chemical reaction between the molecular species, there is a balance between the chemical interactions and the electrostatic dipolar interactions. 1,2,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] Insight into these problems can be gained by comparing adsorption of isomeric molecules. The investigation of molecular isomeric effects in surface science is documented, with most of the emphasis involving chiral surfaces [28][29][30][31][32][33][34][35] or chiral molecules.…”

Substituent effect on the emission behavior of thiazolidinedione derivatives in cationic and anionic micellar media

“…Nonplanar molecules usually have structureless absorption and fluorescence spectra while planar and rigid molecules show absorption and fluorescence spectra with well-resolved vibrational bands. Very often, transition of a molecule from a nonplanar to a more planar and rigid shape, is accompanied with an increase in the quantum yield of fluorescence [40][41][42][43]. Going through the structures of the compounds, it is seen that TZD "A" can exist in two rotameric forms A 1 and A 2 (Scheme 1).…”

Polarization Mediated Chemistry on Ferroelectric Polymer Surfaces

“…Reversible adsorption of weakly adsorbed molecules has been shown to depend on the polarization ferroelectric domain orientation of both organic − and inorganic ferroelectrics. − Such studies have largely investigated polar adsorbate molecules, − with the tacit assumption that nonpolar molecules should be insensitive to the ferroelectric polarization domain orientation. − The chemistry of the surface can play a role and it would be rare, if not unusual, for the surface chemistry of positive and negative ferroelectric domains to be identical. , In this sense, nonpolar molecules would not be immune from the surface dipole direction of a ferroelectric surface. Not only would the nonpolar molecule respond to the dipole direction, as all molecules have a finite polarizability, but surface termination, stoichiometry, and defect densities can differ with different dipole (polarization) directions.…”