Characterization and Modeling of Cis−Trans Photoisomerization of a Trifluoromethoxy-Substituted Metacrylate Copolymer Monolayer at a Fluid Interface

Wüstneck, R.; Fainerman, V. B.; Zauls, V.

doi:10.1021/jp983972q

Cited by 8 publications

(5 citation statements)

References 13 publications

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“…The most probable situation is that three types of entities, namely large aggregates, average dimers, and monomers, are present in the transcritical adsorbed monolayer. However, the rigorous description of this system makes the theoretical model eqs 1−5 rather sophisticated. , As discussed above, for this pressure range the curves presented in Figures −8 were calculated by assuming an equilibrium between monomers and aggregates. For the case where monomers do not exist in the system, the calculations assuming the dimer/aggregate equilibrium lead to results which coincide (at least not too far from the break point) with those obtained for the monomer/aggregate model.…”

Section: Resultsmentioning

confidence: 99%

Dynamic and Equilibrium Surface Pressure of Adsorbed Dodecanol Monolayers at the Air/Water Interface

2000

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A first-order phase transition can occur in adsorbed monolayers of dodecanol dissolved in an aqueous bulk phase. The surface pressure adsorption kinetics Π(t) and Brewster angle microscopy (BAM) studies are effectively combined for characterizing the two-dimensional phase transition. A characteristic break point in the dynamic surface pressure curves indicates the phase transition which is largely affected by the dodecanol concentration in the aqueous solution and on the temperature. Above a certain temperature and below a corresponding bulk concentration, phase transition in the adsorbed monolayer does not occur. After the phase transition point, formation and growth of condensed phase domains are visualized by BAM. The surface pressure-area (Π-A) isotherms of spread dodecanol monolayers show the characteristic main phase transition point indicating two-dimensional condensation of dodecanol in the monolayer. At the same temperature, the surface pressure values of the main phase transition point in the spread dodecanol monolayer are approximately equal to those measured for the adsorbed monolayer. The experimental results can be well-described by the theory of the diffusion kinetics of surfactant adsorption from solutions, which assumes the formation of small and large aggregates in the adsorbed monolayer. The parameters of the theoretical model which describes the state of the spread dodecanol monolayer indicate the formation of average dimers in the precritical expanded region of Π-A isotherms, while in the transcritical region aggregated domains coexist in equilibrium with monomers and average dimers. The standard thermodynamic characteristics calculated are used to compare the adsorption of dodecanol from the aqueous solution and the dodecanol aggregation in the adsorbed monolayer.

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Section: Resultsmentioning

confidence: 99%

Dynamic and Equilibrium Surface Pressure of Adsorbed Dodecanol Monolayers at the Air/Water Interface

2000

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“…30 Wüstneck et al 31,32 adopted a unique approach for estimation of the photoinduced change of an amphiphilic Az containing polymer in surface pressure using a pendant water drop. The surface tension of the drop was determined by axisymmetric drop shape analysis.…”

Section: Macro-size Photomechanical Effectsmentioning

confidence: 99%

Dynamic Photoresponsive Functions in Organized Layer Systems Comprised of Azobenzene-containing Polymers

Seki

2004

Polym J

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ABSTRACT:Azobenzene (Az)-containing polymers provide fascinating photoresponsive actuation systems. When they are organized at interfaces, the motion of Az unit occurring at a molecular (sub-nano) scale can be transferred and amplified to larger scales of materials. This review article focuses to selected research topics on organized layer systems of Az-containing polymers proceeding in our laboratory. They involve i) photomechanical response of monolayers at nanometer levels in thickness and centimeters in area, ii) monolayer-mediated photoorientation of polymer (polysilane) and mesoporous silica at nano-to sub-micrometer levels in thickness, and iii) instant mass migration triggered by patterned photoirradiation occurring at distances over micrometer levels. In every system, strong cooperative interplays between the Az unit and organized molecular or macromolecular assemblies play the essential roles. Promotions of these research areas are anticipated to provide wide and new opportunities for material processing and creation of new classes of photofuncitional soft materials.

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“…In particular, all of the parameters that enter eqs 1 and 2 for the mixture were calculated as the mean weighted values (according to the molar portion of the components in the mixed monolayer) of the parameters of individual monolayers. Obviously, the problem solved in ref was much less complicated than that considered here, because in the present case the composition of the surface layer depends on the time elapsed from the moment when the 2C 11 H 23 -melamine was spread on the aqueous solution of pyrimidine derivative.…”

Section: Theoretical Modelmentioning

confidence: 89%

“…In ref , the Π-A isotherms for spread monolayers comprised of a mixture of cis and trans isomers of trifluoromethoxy-substituted metacrylate copolymers in a given proportion were theoretically described in the framework of an additive model with equations developed in ref quite similar to eqs 1 and 2. In particular, all of the parameters that enter eqs 1 and 2 for the mixture were calculated as the mean weighted values (according to the molar portion of the components in the mixed monolayer) of the parameters of individual monolayers.…”

Section: Theoretical Modelmentioning

confidence: 99%

Molecular Recognition Kinetics of Nonsurface Active Pyrimidine Derivatives Dissolved in the Aqueous Subphase by an Amphiphilic Melamine Type Monolayer: A Theoretical Approach

et al. 2005

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Experimental studies show a drastic change of the characteristic features (Pi-A isotherms, morphology of the condensed phase domains) of the 2C11H23-melamine monolayers by molecular recognition of the pyrimidine derivatives uracil and thymine, largely affected by the reaction kinetics of the recognition process. A new approximate additive theoretical model is introduced for describing the molecular recognition kinetics. The theoretical approach is based on two assumptions: (i) first-order reaction kinetics for the molecular recognition of the nonsurface active pyrimidine derivatives dissolved in the aqueous subphase by the melamine type monolayer and (ii) applicability of the Pi-A isotherm equations derived previously for the description of melamine type monolayers in the fluid (gaseous, LE) state and the phase transition region to the condensed state. The rate constants for the molecular recognition reaction between the melamine type monolayer and the dissolved thymine and uracil are estimated, which are roughly proportional to the bulk concentrations of the pyrimidine derivatives and depend only slightly on the temperature. The theoretical estimates agree satisfactorily with the experimental results obtained under various conditions (Pi = const and dA/dt = const). This fact supports the validity of the first model proposed for the interfacial molecular recognition kinetics with nonsurface active substrates dissolved in the aqueous subphase by complementary hydrogen bonding.

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Characterization and Modeling of Cis−Trans Photoisomerization of a Trifluoromethoxy-Substituted Metacrylate Copolymer Monolayer at a Fluid Interface

Cited by 8 publications

References 13 publications

Dynamic and Equilibrium Surface Pressure of Adsorbed Dodecanol Monolayers at the Air/Water Interface

Dynamic and Equilibrium Surface Pressure of Adsorbed Dodecanol Monolayers at the Air/Water Interface

Dynamic Photoresponsive Functions in Organized Layer Systems Comprised of Azobenzene-containing Polymers

Molecular Recognition Kinetics of Nonsurface Active Pyrimidine Derivatives Dissolved in the Aqueous Subphase by an Amphiphilic Melamine Type Monolayer: A Theoretical Approach

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