Daniel Benczédi - Academia.edu (original) (raw)

Papers by Daniel Benczédi

Journal of Surfactants and Detergents, Dec 23, 2008

The localization and dynamics of fragrance compounds in surfactant micelles are studied systemati... more The localization and dynamics of fragrance compounds in surfactant micelles are studied systematically in dependence on the hydrophobicity and chemical structure of the molecules. A broad range of fragrance molecules varying in octanol/water partition coefficients P ow is employed as probe molecules in an aqueous micellar solution, containing anionic and nonionic surfactants. Diffusion coefficients of surfactants and fragrances obtained by Pulsed Field Gradient (PFG)-NMR yield the micelle/water distribution equilibrium. Three distinct regions along the log(P ow) axis are identified: hydrophilic fragrances (log(P ow) \ 2) distribute almost equally between micellar and aqueous phases whereas hydrophobic fragrances (log(P ow) [ 3.5) are fully solubilized in the micelles. A steep increase of the incorporated fraction occurs in the intermediate log(P ow) region. Here, distinct micelle swelling is found, while the incorporation of very hydrophobic fragrances does not lead to swelling. The chemical structure of the probe molecules, in addition to hydrophobicity, influences fragrance partitioning and micelle swelling. Structural criteria causing a decrease of the aggregate curvature (flattening) are identified. 2 H-NMR spin relaxation experiments of selectively deuterated fragrances are performed monitoring local mobility of fragrance and leading to conclusions about their incorporation into either micellar interface or micelle core. The tendencies of different fragrance molecules (i) to cause interfacial incorporation, (ii) to lead to a flattening of the micellar curvature and (iii) to incorporate into micelles are shown to be correlated.

Chemistry: A European Journal, Aug 6, 2021

Despite their intrinsic hydrolysable character, imine bonds can become remarkably stable in water... more Despite their intrinsic hydrolysable character, imine bonds can become remarkably stable in water when self-assembled in amphiphilic micellar structures. In the present article, we systematically study some of these structures and the influence of various parameters that can be used to take control over their hydrolysis, including pH, concentration, position of the imine function in the amphiphilic structure, relative lengths of the linked hydrophilic and hydrophobic moieties. Thermodynamic and kinetic data lead us to the rational design of stable imines in water, partly based on the location of the imine function within the hydrophobic part of the amphiphile and on a predictable quantitative term that we define as the total hydrophilic-lipophilic balance (HLB). In addition, we show that such stable systems are also stimuli-responsive and therefore, of potential interest in trapping and releasing micellar components on demand.

Chemistry & Biodiversity, Nov 1, 2014

A series of thioether profragrances was prepared by reaction of different sulfanylalkanoates with... more A series of thioether profragrances was prepared by reaction of different sulfanylalkanoates with δ-damascone and tested for their release efficiencies in a fabric-softener and an all-purpose cleaner application. Dynamic headspace analysis on dry cotton and on a ceramic plate revealed that the performance of the different precursors depended on the structure, but also on the particular conditions encountered in different applications. Moreover, profragrances derived from other α,β-unsaturated fragrance aldehydes and ketones were synthesized analogously and evaluated using the same test protocol. Thioethers were found to be suitable precursors to release the corresponding fragrances, but neither the quantity of profragrance deposited from an aqueous environment onto the target surface, nor the amount of fragrance released after deposition could be linearly correlated to the hydrophilicity or hydrophobicity of the compounds. Different sets of compounds were found to be the best performers for different types of applications. Only one of the compounds evaluated in the present work, namely the thiolactic acid derivative of δ-damascone, efficiently released the corresponding fragrance in both of the tested applications. Profragrance development for functional perfumery thus remains a partially empirical endeavour. More knowledge (and control) of the various application conditions are required for an efficient profragrance design.

ACS Sustainable Chemistry & Engineering, Feb 24, 2022

Advanced Functional Materials, Nov 8, 2016

Macromolecules, Apr 21, 1998

This paper presents a theoretical and experimental study of the sigmoidal water sorption isotherm... more This paper presents a theoretical and experimental study of the sigmoidal water sorption isotherms of amorphous starch. Sorption isotherms have been measured by gas chromatography at infinite dilution of water in starch and by isothermal and isosteric sorption experiments in an extended concentration and temperature range in which the biopolymer behaves either as a brittle glass or as a rubbery melt. A maximum value of the isothermal activity coefficient of water is observed at a composition corresponding to the glass transitions measured by calorimetry. Therefore, the partial derivatives of the activity coefficient of water with respect to concentration and temperature are positive in glasses and negative in melts. A transition from sigmoidal to Flory type sorption is estimated to occur at 175°C, which is lower than the glass transition of dry starch. The distribution of water molecules in glasses and melts is analyzed with the Kirkwood theory of solutions. In glasses, water shows large negative excluded volumes typical of an antiplasticizer, as reflected also in the density increase observed at low water concentrations. In melts, water shows positive excluded volumes typical of a plasticizer having recovered its motional freedom restricted in the glassy state. Up to 80°C, the self-clustering functions of water in melts diverge at higher water contents. These functions only take finite values above this temperature once a full melting of the starch-starch hydrogen bond interaction has occurred. The sigmoidal water sorption isotherms are analyzed with a new explicit relationship combining the generalized Freundlich adsorption model and the Flory model of polymer solutions. A restricted translational and rotational freedom is predicted for the adsorption water, and a clustering tendency is predicted for the solution water. The Freundlich-Flory sorption model provides a consistent description of the solvation, the swelling, and the dissolution of hydrophilic polymer glasses in a solvent like water whereas the Brunauer-Emmet-Teller model is only physically meaningful for the adsorption of nonsolvents such as oxygen or nitrogen gases.

ACS Applied Materials & Interfaces, Aug 30, 2022

Journal of Applied Polymer Science, Oct 21, 2013

Microencapsulation is becoming increasingly important in the food, cosmetics, and medicinal indus... more Microencapsulation is becoming increasingly important in the food, cosmetics, and medicinal industries due to its potential for stabilization and delivery of volatile and delicate compounds. Novel food-safe techniques for encapsulating oil in silk biomaterials using emulsion-based processes that exploit silk's unique properties (including amphiphilicity, biocompatibility, aqueous and ambient processing, and tunable physical crosslinking behavior) are described. The sonication-induced self-assembly of silk previously applied to hydrogel fabrication replaced the use of the thermal or chemical suspension crosslinking traditionally used to stabilize the aqueous protein phase in emulsions. Stable, physically crosslinked silk micro-and macro-particles loaded with oil or water-soluble dye were produced by aliquoting sonicated silk solutions into an oil bath. Oil micro-droplets emulsified in aqueous silk solutions did not impede the self-assembly of silk into films or hydrogel networks. In O/W/O emulsions, particle morphology and silk permeability to a model lipophilic dye in the interior phase were controllable via processing.

Advanced theory and simulations, Jul 22, 2019

Models of deposition and detachment dynamics of different shaped anisotropic colloids are reporte... more Models of deposition and detachment dynamics of different shaped anisotropic colloids are reported to understand how equilibrium deposited amounts compare to spherical colloids. For different shaped colloids including spheres, ellipsoids, toroids, and buckled particles with varying aspect ratios, interaction potentials with substrates are computed using the Derjaguin approximation. Using these potentials, the Smoluchowski equation is used to model the dynamics of deposition and detachment versus particle-substrate attraction and aspect ratio for each particle shape. Average times for deposition and detachment and their ratio show steady-state deposited amounts can be enhanced by several orders of magnitude for different particle shapes compared to spherical colloids of the same volume. From a mechanistic standpoint, the present findings indicate how local Gaussian curvature of different particle shapes can lead to stronger adhesive interactions, longer detachment times, and higher deposited amounts compared to spherical colloids, which provides general design rules for controlling and optimizing colloidal deposition.

ACS Applied Materials & Interfaces, Mar 3, 2020

Total internal reflection microscopy (TIRM) is used to directly, sensitively, and simultaneously ... more Total internal reflection microscopy (TIRM) is used to directly, sensitively, and simultaneously measure colloidal interactions, dynamics, and deposition for a broad range of polymer-surfactant compositions. A deposition state diagram containing comprehensive information about particle interactions, trajectories, and deposition behavior is obtained for polymer-surfactant compositions covering four decades in both polymer and surfactant concentrations. Bulk polymer-surfactant phase behavior and surface properties are characterized to provide additional information to interpret mechanisms. Materials investigated include cationic acrylamide-acrylamidopropyltrimonium (AAC) copolymer, sodium lauryl ether sulfate (SLES) surfactant, silica colloids, and glass microscope slides. Measured colloid-substrate interaction potentials and deposition behavior show non-monotonic trends vs. polymer-surfactant composition and appear to be synergistic in the sense that they are not easily explained as the superposition of single component mediated interactions. Broad findings show at some compositions polymer-surfactant complexes mediate bridging and depletion attraction that promote colloidal deposition, whereas, other compositions produce electrosteric repulsion that deters colloidal deposition. These findings illustrate mechanisms underlying colloid-surface interactions in polymer-surfactant mixtures, which is important to controlling selective colloidal deposition in multi-component formulation applications.

Trends in Food Science and Technology, 1999

Crystal Growth & Design, Jun 21, 2013

ABSTRACT

Particle & Particle Systems Characterization, Jul 25, 2017

Interactions between macromolecular systems and biosurfaces are complicated by both the complexit... more Interactions between macromolecular systems and biosurfaces are complicated by both the complexity of these multivalent interactions and challenges in quantifying affinities. A library of gold nanoparticles (AuNPs) as multivalent probes is used to quantify biosurface affinity, using hair as a model targeted substrate. Keywords gold nanoparticle; ICP-MS; imaging Understanding and engineering the interactions of synthetic and biomolecular systems with biosurfaces is an important issue in health and personal care. Adsorption to skin is a key feature for drug delivery systems, [1] wound healing, [2] and cosmetics. [3] Adsorption to hair and natural fibers is key for many biological processes such as pollination, [4] locomotion [5] and sensing, [6] and is critical for consumer products within the haircare field. [7] In all of these systems, understanding supramolecular interactions with surfaces is required to tune both the strength and reversibility of adsorption. Elucidation of the effects of size, shape, charge, functionality and structure of materials on interactions with biosurfaces is a challenging task. [8] Most understanding regarding interactions of synthetic and bio-system with biosurfaces is on the charge of each components, such as electrostatic forces between two opposing charged systems. [9,10] The supramolecularly competitive aqueous environment in which these surfaces function makes multivalent interactions a prerequisite. For this reason, polymers have been used as multivalent platforms to study adsorption to hair and skin. [11] The flexibility of the polymer chain and accessibility of backbone functionalities, however, complicate the interpretation of the individual supramolecular interactions involved in the adsorption process. Most understanding regarding. Monolayer-protected nanoparticles serve as excellent scaffolds to study supramolecular interactions. These systems provide a non-interactive "tabula rasa" that can be decorated with specific chemical functionalities presenting on the particle surface. [12] These surface-Le et al.

Polymer Chemistry, 2015

Please note that technical editing may introduce minor changes to the text and/or graphics, which... more Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal's standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains.

Journal of Coatings Technology and Research, May 2, 2015

Various techniques have been employed to entrap fragrant oils within microcapsules or micropartic... more Various techniques have been employed to entrap fragrant oils within microcapsules or microparticles in the food, pharmaceutical, and chemical industries for improved stability and delivery. In the present work we describe the use of silk protein microparticles for encapsulating fragrant oils using ambient processing conditions to form an all-natural biocompatible matrix. These microparticles are stabilized via physical crosslinking, requiring no chemical agents, and are prepared with aqueous and ambient processing conditions using polyvinyl alcohol-silk emulsions. The particles were loaded with fragrant oils via direct immersion of the silk particles within an oil bath. The oil-containing microparticles were coated using alternating silk and polyethylene oxide layers to control the release of the oil from the microspheres. Particle morphology and size, oil loading capacity, release rates as well as silk-oil interactions and coating treatments were characterized. Thermal analysis demonstrated that the silk coatings can be tuned to alter both retention and release profiles of the encapsulated fragrance. These oil containing particles demonstrate the ability to adsorb and controllably release oils, suggesting a range of potential applications including cosmetic and fragrance utility.

Wiley-Blackwell eBooks, Jan 15, 2010

Journal of Molecular Liquids, May 1, 2021

Abstract Small amounts of nonpolar additives can have a tremendous impact on viscosity and viscoe... more Abstract Small amounts of nonpolar additives can have a tremendous impact on viscosity and viscoelasticity of giant micelles and completely change macroscopic properties. The effect can be best understood with the establishment of complete salt curves by screening surfactant viscosity as a function of electrolyte concentration. From previous studies in micellar systems of sodium laureth sulfate (SLES) with fragrance molecules, two independent mechanisms could be identified, co-solvent type interactions leading to a decrease of the maximum viscosity, and co-surfactant type interactions that cause the salt curve shift to the left. Our studies here reveal two new mechanisms with different effects on the salt curve. In particular, with long-chain hydrocarbons from n-octane to n-tetradecane a right shift was observed, whereas with short-chain or cyclic hydrocarbons such as n-hexane or cyclohexane the maximum viscosity increases. The two effects are interpreted via an extension of a recently developed thermodynamic model where changes in viscosity can be rationalized by a rebalance of the relative concentration of the three co-existing microphases: endcaps, cylinders and branching points. The right shift is linked to a continuous transformation of giant micelles into microemulsions containing an internal fluid. On the other hand, viscosity at maximum scales with the generalized bending constant of the molecular film forming the three microphases of the surfactant system. The total of four proposed mechanisms of solute-surfactant interactions that can impact amplitude and position of salt curves are independent and of different origin, but they are all intimately linked to the location of the additives within the surfactant film: headgroup, micellar interface, surfactant tail region or micellar core. Further investigation will be necessary to understand the molecular driving forces that position nonpolar additives within micellar aggregates, which would be the key for successful prediction of their impact on macroscopic viscosity.

RSC Advances, 2014

The volatile nature of olfactory compounds has led to the development of pro-fragrances, which sl... more The volatile nature of olfactory compounds has led to the development of pro-fragrances, which slowly release the active fragrance molecules upon cleavage of a chemical bond to a substrate. Based on the hypothesis that monosaccharide motifs could serve to effectively anchor pro-fragrances on cotton, which is an important requirement for use in laundry products, we investigated new galactose-based pro-fragrances. A retro 1,4-Michael-type reaction was employed as the release mechanism. Thus, δdamascone was reacted in a 1,4-addition with mercaptoacetic acid, and the product was coupled with 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose. To explore the influence of the molecules' polarity on the deposition and release kinetics, both the isopropylidene-protected hydrophobic as well as the deprotected hydrophilic pro-fragrance were studied. The fragrance release was investigated in aqueous solution by 1 H-NMR spectroscopy as a function of pH; the data show that both pro-fragrances are stable under acidic conditions, but release the δ-damascone under basic conditions. The release kinetics are well described by a first-order process, and observed to be much faster in case of the isopropylideneprotected hydrophobic pro-fragrance. The fragrance release from washed and dried cotton tissue was investigated via dynamic headspace analysis followed by gas chromatography-mass spectroscopy. The data show that the deposition from solution is much better for the hydrophobic pro-fragrance, that the δ-damascone is slowly released in both cases, and that the amount of δ-damascone that can be released is increased by over two orders of magnitude higher than in the case of tissue washed with the neat fragrance under identical conditions.

Applied Clay Science, Feb 1, 2013

The intercalation of biosurfactants (lysolecithin and lecithin) in layered clay mineral supports ... more The intercalation of biosurfactants (lysolecithin and lecithin) in layered clay mineral supports was investigated to assess the suitability of the resulting nanohybrid materials as flavor and fragrance delivery system. The protonated biosurfactant molecules (pH = 2.3) were intercalated into the Na-montmorillonite, whereas the deprotonated biosurfactants (pH~12) were intercalated into Mg-Al layered double hydroxides. The amount of lysolecithin and lecithin bound to the layered adsorbents was estimated by measuring adsorption isotherms. The basal spacing obtained from X-ray diffraction measurements suggested that the molecules are arranged in parallel with the layers of montmorillonite, whereas in the case of layered double hydroxides, the adsorbed molecules are in a vertical position between the layers. The interaction of layered adsorbents and biosurfactants was further evidenced by infrared spectroscopy. The intercalated montmorillonite and LDH particles were then probed for their ability to intercalate limonene molecules. Only the lysolecithins modified samples adsorbed limonene. The theoretical sizes of molecules and their possible arrangement between the layers were modeled by HyperChem 7.0 molecular calculations to correlate the ability to bind the lecithins in the confined space of the layered materials.