FG Physikalische Chemie / Molekulare Materialwissenschaften

15 Items

Recent Submissions
Changes in Phase Behavior from the Substitution of Ethylene Oxide with Carbon Dioxide in the Head Group of Nonionic Surfactants

Spiering, Vivian Jeannette ; Ciapetti, Aurora ; Tupinamba Lima, Michelle ; Hayward, Diminic W. ; Noirez, Laurence ; Appavou, Marie-Sousai ; Schomäcker, Reinhard ; Gradzielski, Michael (2019-11-25)

Nonionic ethylene oxide (EO)‐based surfactants are widely employed in commercial applications and normally form gel‐like liquid crystalline phases at higher concentrations, rendering their handling under such conditions difficult. By incorporating CO2 units in their hydrophilic head groups, the consumption of the petrochemical EO was reduced, and the tendency to form liquid crystals was suppres...

The interaction of hydrogen with CeO2 (111)/Ru (0001) and surface action spectroscopy

Plucienik, Agata (2019)

The first part of this thesis describes the setup of an apparatus for vibrational surface action spectroscopy as well as first experiments with this new method employing infrared radiation from the free electron laser of the Fritz Haber Institute. Vibrational action spectroscopy has been used previously mostly for the characterization of clusters in the gas phase. We have extended this method t...

Neutralisation rate controls the self-assembly of pH-sensitive surfactants

Hayward, Dominic W. ; Chiappisi, Leonardo ; Teo, Jyh Herng ; Prévost, Sylvain ; Schweins, Ralf ; Gradzielski, Michael (2019-10-14)

The degree of ionisation of a weakly acidic surfactant can be continuously modified from nonionic to ionic by adjusting the pH. This property can be used to control the curvature and therefore the morphology of the self-assembled aggregates it forms in solution. Herein, we report the surprising phenomenon, observed in the alkyl ether oligo(ethylene oxide) carboxylate (CH3(CH2)11/13OEO4.5CH2COOH...

The interaction of soft Silica nanoparticles with phospholipid membranes

Bekir, Marek (2019)

In last decades, the study of the interaction between inorganic nanoparticles and phospholipid mem-branes gained more attention as it may enable new attractive application possibilities in nanomedicine. In this context vesicles composed of phospholipid membranes serve as a model for biological mem-branes. Furthermore, the interaction with more or less soft nanoparticles has a great relevance, a...

Synthesis and characterization of poly((2-dimethylamino)ethyl methacrylate) (PDMAEMA) modified silica nanoparticles

Altin, Burcu (2019)

In this work, we described a multi-step route for preparation of a pH responsive polymer, 2-(dimethylamino) ethyl methacrylate (DMAEMA), grafted silica nanoparticles with a size of 10- 100 nm in diameter via surface initiated- atom transfer radical polymerization (SI-ATRP). We prepare as a starting point well-defined silica nanoparticles (SNPs) by means of amino acid-based catalysis (L-Arginine...

Structural Analysis of a Modern o/w-Emulsion Stabilized by a Polyglycerol Ester Emulsifier and Consistency Enhancers

Dahl, Verena ; Friedrich, Achim ; Meyer, Jürgen ; Venzmer, Joachim ; Belkoura, Lhoussaine ; Strey, Reinhard ; Mayer, Christian ; Michel, Raphael ; Gradzielski, Michael (2018-01-18)

The aim of our work was to study the structure of a typical modern cosmetic oil-in-water emulsion (o/w-emulsion), based on the emulsifier polyglyceryl-3 dicitrate/stearate and glycerylstearate/stearyl alcohol as consistency enhancer. We have used a systematic approach building up the cosmetic emulsion step by step, characterizing all systems by using Small Angle Neutron Scattering (SANS), Diffe...

Gels Obtained by Colloidal Self-Assembly of Amphiphilic Molecules

Malo de Molina, Paula ; Gradzielski, Michael (2017-08-03)

Gelation in water-based systems can be achieved in many different ways. This review focusses on ways that are based on self-assembly, i.e., a bottom-up approach. Self-assembly naturally requires amphiphilic molecules and accordingly the systems described here are based on surfactants and to some extent also on amphiphilic copolymers. In this review we are interested in cases of low and moderate...

Droplets, Evaporation and a Superhydrophobic Surface: Simple Tools for Guiding Colloidal Particles into Complex Materials

Sperling, Marcel ; Gradzielski, Michael (2017-05-04)

The formation of complexly structured and shaped supraparticles can be achieved by evaporation-induced self-assembly (EISA) starting from colloidal dispersions deposited on a solid surface; often a superhydrophobic one. This versatile and interesting approach allows for generating rather complex particles with corresponding functionality in a simple and scalable fashion. The versatility is base...

Controlling the formation of vesicle structures and their fixation by polymerization

Yalcinkaya, Hacer (2019)

In recent years, nanostructures have drawn much interest due to their potential applications in biomedicine, energy conversion, detergency or electronics. Controlling their formation and stability is one of the key issues to obtain such versatile structures with enhanced morphological properties. Especially vesicles are interesting nanostructures with their hollow spherical geometry, allowing e...

Facile Control over the Supramolecular Ordering of Selfassembled Peptide Scaffolds by Simultaneous Assembly with a Polysacharride

Li, Rui ; Boyd-Moss, Mitchell ; Long, Benjamin ; Martel, Anne ; Parnell, Andrew ; Dennison, Andrew J. C. ; Barrow, Colin J. ; Nisbet, David R. ; Williams, Richard J. (2017-07-06)

Enabling control over macromolecular ordering and the spatial distribution of structures formed via the mechanisms of molecular self-assembly is a challenge that could yield a range of new functional materials. In particular, using the self-assembly of minimalist peptides, to drive the incorporation of large complex molecules will allow a functionalization strategy for the next generation of bi...

A small-angle neutron scattering environment for in-situ observation of chemical processes

Hayward, Dominic W. ; Chiappisi, Leonardo ; Prévost, Sylvain ; Schweins, Ralf ; Gradzielski, Michael (2018-05-08)

A new sample environment for the observation of ongoing chemical reactions is introduced for small-angle neutron scattering (SANS) experiments which enables structural changes to be followed continuously across a wide Q-range in response to changes in the chemical environment. The approach is demonstrated and validated by performing single and multiple potentiometric titrations on an aqueous an...

Protein adsorption on nanostructured silica surfaces

Meißner, Jens (2018)

This Ph.D. thesis presents a study of the interaction of globular proteins with nanostructured silica surfaces. It aims to gain a better understanding of the consequences of a high surface curvature and confinement on the adsorption behavior and morphology of the adsorbed protein. The adsorption behavior of lysozyme and 𝛽-lactoglobulin on silica nanoparticles was studied from pH 2 to 11 and ...

Scattering techniques for nanoparticle analysis

Breßler, Ingo (2017)

This work presents three program packages implementing different methods for nanoparticle analysis, focusing on the quantitative determination of particle size distributions required in standardization of nanoparticle reference materials. In part one, classical curve fitting is discussed. It finds optimal parameters of a scattering model composed of analytical expressions. The classical curve ...

Enhancing the stability of spontaneously self-assembled vesicles - the effect of polymer architecture

Bressel, Katharina ; Gradzielski, Michael (2015)

The formation of stable vesicles with a controlled size and high stability is an important matter due to their wide application in pharmaceutical and detergency formulations and as drug delivery vehicles. One can control the size of spontaneously formed vesicles in mixtures of zwitterionic and anionic surfactants by the admixture of small amounts of an amphiphilic copolymer of the PEO-PPO-PEO t...

Introduction to the special issue on small-angle scattering

Gradzielski, Michael ; Allen, Andrew J. (2016)