1st Symposium on Colloid and Interface Science

The scientific program will consist of invited and contributed talks as well as poster-like sessions. The presentation time will be: 45 minutes for invited talks (plus 10 minutes for Q & A), 15 minutes for contributed talks (plus 5 minutes for Q & A) and 5 minutes for the virtual posters. All the talks and sessions will be held remotely via Zoom.

Keynote speakers

Coalescence of crude oil droplets in EOR context

Jean-François Argillier

IFP Energies nouvelles, France

Abstract

The treatment of produced water during chemical enhanced oil recovery (EORc) is one of the main concerns of the oil industry. In order to be able to propose solutions for improving liquid/liquid separation processes in water treatment, it is necessary to understand the behaviour of oil droplets with regard to emulsion destabilisation phenomena. Firstly, a multi-scale strategy combining several characterisation techniques has been proposed in order to study the impact of salts, polymers and surfactants on the behaviour of oil droplets. The results of this work provided a better understanding of the destabilisation phenomena within emulsions. The salts (NaCl and CaCl₂) in solution promote the coalescence and flocculation of oil droplets by reducing the electrostatic repulsion between the water/oil interfaces. The surface charge of the droplets is reduced in the presence of salt due to the screening of the charges and to the reduction of solubility of the oil's natural surfactants in the aqueous phase. The presence of high molecular polymer in solution has several opposing effects on the behaviour of the oil droplets. First of all, it reduces the creaming of the oil droplets by increasing the viscosity of the continuous phase, but it promotes the formation of flocks which accelerate the creaming kinetics. In addition, this polymer reduces the drainage velocity of the aqueous thin film. Finally, SDBS in solution reduces the interfacial tension between the phases and increases the surface charge of the oil droplets by adsorbing at the interfaces. However, the natural surfactants in the oil interfere in presence of SDBS leads to the formation of a complex system that evolves over time (transfer / reorganisation of the interface) which could lead to the destabilisation of the produced water.

Phase separations and asymmetries in emulsion-templated vesicles

Laura R. Arriaga

Department of Theoretical Condensed Matter Physics, Universidad Autónoma de Madrid, Spain

Abstract

A vesicle is a naturally existing or an artificially prepared aqueous droplet stabilized by an amphiphilic membrane that ensures retention of hydrophilic ingredients within its core. This amphiphilic membrane typically comprises two leaflets, which have either identical or different compositions. While membranes comprising two compositionally identical leaflets exhibit lateral asymmetries or domains if prepared from mixtures of amphiphilic molecules capable of phase separation, membranes comprising compositionally different leaflets are asymmetric in the transversal direction. Moreover, membraneless compartments can be created within vesicles through the phase separation of sufficiently concentrated polymer solutions encapsulated in their cores. These phase separations or asymmetries dictate vesicle properties, enabling a wide range of applications. However, the utility of these vesicles depends critically on the degree of control achieved over their properties in the fabrication process. Here, we address the adequacy of emulsion droplets with well-controlled topologies, fabricated with exquisite control by microfluidic technologies, as vesicle templates. In particular, we describe a first strategy to fabricate vesicles with symmetric membranes exhibiting lateral domains and internal compartments using double emulsion drops as templates [1,2], and a second strategy to form vesicles with asymmetric membranes using triple emulsion drops as templates [3]. These strategies efficiently encapsulate ingredients within the core of the vesicles or their membranes and yield vesicles with monodisperse sizes and controlled degrees of asymmetry. We are currently exploiting these fabrication strategies to develop vesicles capable of moving on substrates using their interaction with magnetic microparticles that can be actuated with rotating magnetic fields.

[1] L.R. Arriaga, S. Datta, S.-H. Kim, E. Amstad, T. Kodger, F. Monroy, D.A. Weitz. Ultra- thin shell double emulsion templated giant unilamellar lipid vesicles with controlled microdomain formation. Small 10, 950-956 (2014).

[2] J. Perrotton, R. Ahijado-Guzman, L.H. Moleiro, B. Tinao, A. Guerrero-Martinez, E. Amstad, F. Monroy, L.R. Arriaga. Microfluidic fabrication of vesicles with hybrid lipid/nanoparticle bilayer membranes. Soft Matter 15, 1388-1395 (2019).

[3] L.R. Arriaga, Y. Huang, S.-H. Kim, J.L. Aragones, R. Ziblat, S.A. Koehler, D.A. Weitz. Single-step assembly of asymmetric vesicles. Lab Chip 19, 749-756 (2019).

Natural Surfactant Extracted From Plants: Surface Properties and Cleaning Ability

Amitabha Bhattacharyya

Department of Physics, Sikkim University, Gangtok, India

Abstract

Amphiphilic nature of the surfactant molecules is responsible for reduction of surface tension of water having varied applications in domestic and industrial purpose. Once the surfactant enter into the aquatic environment its causes damages, leading to large environmental burden. Keeping this in view, it is desirable to find an alternative to synthetic surfactants which is bio-compatible, one of which could be plant based natural surfactants.

This study exhibits surfactant properties and preliminary analysis of four plant based natural surfactants called saponin extracted from Acacia concinna (Shikakai), Mucuna gigantea (Hamburger Seed), Albizia procera (Seto Siris), and Zephyranthes carinata (Pyagi Phool). These plants have been traditionally used in cleaning and could be used as biodegradable and renewable alternatives. The inside of the seeds of Hamburger have been traditionally used as soap and the outer cover as face wash. Seto Siris pods and leaves have been used for cleaning jewelry since ancient time.

The results show that saponins are acid balanced, biodegradable and renewable surfactants with a low critical micelle concentration. All the natural surfactants exhibit prominent surface tension reduction, high foaming and cleaning. They are at par with synthetic surfactants in terms of foaming and cleaning. Emulsion stability of natural surfactants decreases in the region of micelle formation. The natural surfactants have a potential to be used as a surface active agent. Our results suggest these plant derived natural surfactants have remarkable surface active properties and can provide useful input to food and cosmetic industries as bio-degradable eco-friendly surfactants.

Keywords: Saponin, Surface tension, Foam, Natural Surfactants

Structural composition and highly viscoelastic behaviour of a-Cyclodextrin - surfactants films at the water/air interface

José Campos-Terán

Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana, Unidad Cuajimalpa, Mexico

Abstract

The bulk and surface properties of aqueous α-cyclodextrins (α-CD) / surfactant mixtures have been extensively studied with a variety of techniques. In particular the surface rheological behavior, both the dilatational and shear rheology have proven to be very useful to understand the nature of adsorbed films in many areas ranging from medical diagnostics to oil recovery.

In this work, experimental and modelling results on α-CD-surfactant complexes films at the water/air interface will be presented.^1,2,3 In particular, anionic surfactants (n-alkyl sulfates (C_nSO₄) with n = 8 to 14, and the sulfonate C₁₂SO₃) were found to spontaneously form remarkable viscoelastic films at aqueous solution/air interfaces, the magnitude of which has not been observed in similar systems. Temperature, concentration, alkyl chain length and the number of surfactants employed strongly modify their viscoelastic properties. A large number of surface techniques were used to characterize the films, namely shape-response measurements to volume perturbations on drop hanging from a capillary, neutron reflectivity, Brewster angle microscopy and dynamic surface tension. To quantify their viscoelastic behavior, the continuous injection and oscillating drop methods were used. It was found that the viscoelastic behavior is strongly related to the distribution of species in the bulk solution (measured by isothermal titration calorimetry), in particular to the high concentration of α-CD₂-surfactant inclusion complexes, but also to their relative surface activity.

Figure 1: Viscoelastic behavior of a α-CD- anionic surfactant solution as a function of alkyl length chain.

References

1 A. Luviano, J. Hernández-Pascacio, D. Ondo, R. A. Campbell, A. Piñeiro, J. Campos-Terán, M. Costas, Journal of Colloid and Interface Science, 2020, 565, 601–613; doi: 10.1016/j.jcis.2019.12.012

2 Pablo F. Garrido, Martín Calvelo, Rebeca Garcia-Fandiño and Ángel Piñeiro, Biomolecules, 2020, 10, 431; doi:10.3390/biom10030431

3 J. Roberto Romero-Arias, Alberto S. Luviano, Miguel Costas, Aurora Hernández Machado and Rafael A. Barrio, Soft Matter, 2021,17, 2652-2658; doi: 10.1039/D0SM01796E

Measurement of the force between colloidal particles trapped at a flat air/water interface

Rolando Castillo

Instituto de Física, Universidad Nacional Autónoma de México, Mexico

Abstract

The radial attraction between microspheres straddling at the air/ water interface (Bond number <<1), whose origin is the irregular shape of the contact line and its concomitant distortion of the water surface, is measured using two light beams of a time-sharing optical tweezer. The colloidal particles used to make the measurements are of two types: a) Microspheres made of hydrophobically covered silica to reduce the electrostatic interactions to a minimum, and b) Non-metallic spherical Janus particles, where one face of the particles is hydrophilic, and the other one, hydrophobic. For the first case, the measured radial force goes as a quadrupolar power law, r ^-5. For the second case, depending on the chosen particles, the measured force goes from almost pure quadrupolar to almost pure hexapolar interaction due to the three-phase contact line corrugation. Measured force curves are modeled as a sum of power laws, Ar^-5 + Br^-7 + Cr^-6, obtained from an expansion in capillary multipoles.

Study of PVA-nanoparticle suspensions with antibacterial properties

Christian Gómez Solís

Departamento de Ingeniería Física, Campus León, Universidad de Guanajuato, Mexico

Abstract

The use of nanoparticles suspended in polymer solutions is a solution to prevent the spread of bacteria on surfaces. In the present work, a polymer suspension containing complexes of silver citrate and copper ions was developed, which when deposited on a surface polymerize forming a film, which when irradiated with different wavelengths (394, 405, 532 nm) form different nanoparticles, which have antibacterial activity. The E. Coli inhibition and elimination tests were performed with disc and growth tests in Petri dishes. A comparison was made with suspensions of nanoparticles of ZnO, showing that the suspensions with complexes of Ag and Cu are more efficient in reducing the number of colonies in less than 5 min.

Multiple nanoemulsions: leveraging interface science to scale up production while scaling down size

Matthew E. Helgeson

Department of Chemical Engineerieng, University of California – Santa Barbara, USA

Abstract

Multiple emulsions – i.e., droplets within droplets – have opened new frontiers in research and technology for “designer” emulsions where chemistries and processes can be compartmentalized to control encapsulation and chemical reactions within droplets, providing utility in consumer formulations, pharmaceuticals and particulate materials design. However, most existing processes for multiple emulsions are limited to producing large droplets at low throughput (e.g. microfluidics) or droplets with significant size and morphology dispersity (e.g. bulk mechanical emulsification). Here, we review several recent successes in the development of scalable processes to produce multiple nanoemulsions, and the interesting colloid and interface science they rely upon [1]. In particular, we focus on single-step emulsification methods that combine high-energy emulsification with co-surfactant systems that simultaneously possess ultra-low interfacial tension and frustrated spontaneous curvature. Using a simple modification of the Helfrich model for the interfacial free energy to include the thermodynamics of co-surfactant mixtures, we show that such a situation leads to the thermodynamically metastable formation of nanodroplets with multiple internal interfaces. Predictions of the model are consistent with experiments, which indicate a “state diagram” that contains a wealth of preferred droplet structures including uniform, core-shell and multi-shell morphologies. We show that the geometry and properties of these multi-phase nanodroplets can be finely tuned through co-surfactant formulation, and ultimately demonstrate the ability of multi-nanoemulsions to serve as templates for multi-phase nanoparticles with a number of potential applications.

[1] T. Sheth, T. Prileszky, S. Seshadri and M.E. Helgeson, “Multiple Nanoemulsions”, Nature Reviews Materials, 2020, 5(3): 214-228. DOI: 10.1038/s41578-019-0161-9

Properties of surfactant monolayers and their relation to microemulsions, emulsions and foams properties

Dominique Langevin

Laboratoire de Physique des Solides, Université Paris-Saclay, France

Abstract

Surfactants form monolayers at the air-water and oil-water interface, which can be characterized by a number of properties: surface tension, static and dynamic, surface curvature elasticity, surface compression and surface shear elasticities and viscosities. We will show how the knowledge of these properties allows predicting the behavior of oil/water or air/water dispersions. For instance, for microemulsions that are thermodynamically stable dispersions, one can predict dispersion type and size, as well as interfacial tensions between microemulsions, oil and water. For emulsions and foams that are thermodynamically unstable dispersions, the prediction of dispersion type and size is more difficult and will be discussed. Surfactant layer properties also control the destabilization processes: gravity effects (creaming, sedimentation, drainage), Ostwald ripening and coalescence of drops or bubbles (although in this case experimental evidence is still scarce).

Tailoring the interfacial assembly and the mechanical response of colloidal and biological systems

Armando Maestro

Institut Laue – Langevin, Grenoble, France

Abstract

Fluid interfaces can be used as a platform for promoting the direct and spontaneous self-assembly of colloidal systems, including amphiphilic molecules, macromolecules and organic and metallic nanoparticles, where the driving force is the reduction in interfacial energy. Besides, fluid interfaces allow fine-tuning of the ensemble of molecules by an external force, such as the presence of an imposed interfacial flow, or by engineering the molecular interactions dictated by the interplay of interfacial forces. As a consequence, a wide-ranging set of interfacial structures can be achieved: from liquid-like layers, which can flow under stress, to amorphous solids that can sustain static stress [1].

In this talk, I will first discuss different ways of quantitatively tuning and tailoring the mechanical response and the interfacial assembly of colloidal systems confined at fluid interfaces. In particular, I will focus on the link between the structure, measured by neutron reflectivity and ellipsometry, and the mechanical properties (employing different shear probes) of different versatile systems that we have studied lately: Ligand-coated spherical silica nanoparticles, synthetic soft microgel particles (based on chemically cross-linked acrylamide polymers), graphene oxide sheets, and very recently surfactant/polyelectrolyte mixtures and lipid nanoparticles [1, 2].

In the second part of the talk, I will report different experimental investigations involving phospholipids and proteins (and peptides) recreating, by in vitro models based on Langmuir monolayers studied by neutron scattering, relevant biophysical processes happening at biomembrane surfaces. For example, the first stage of endocytosis, by studying the composition, structure and mechanics of a complex layer formed by protein/lipids that self-assembles in stages generating membrane curvature.

References

[1] A. Maestro, Current Opinion in Colloid and Interface Science, 2019, 39, 232;

[2] A. Maestro & P. Gutfreund, Advances in colloid and Interface Science, 2021, In press.

Unravelling the Role of Temperature and Electrostatics in the Surface Conformation of Charged Microgel Particles

Julia Maldonado-Valderrama

Departamento de Física Aplicada, Universidad de Granada, Spain

Abstract

Thermoresponsive microgels based on poly-N-isopropylacrylamide (PNIPAM) have many biomedical applications owing to their biocompatibility and their Volume Phase Transition Temperature (VPTT) being around the physiological temperature. Understanding the surface structure of PNIPAM microgels in monolayers is important in terms of fundamental science and towards their application in the development of thermoresponsive emulsions. However, to date there are still very few works reporting specifically the PNIPAM monolayers above and below the VPTT. In addition, the role of electrostatics in surface films of charged microgels remains controversial. Hence, in the present paper, we study the surface conformation of charged PNIPAM at different swelling states. Shrunken PNIPAM microgels in bulk show higher effective charge than swollen microgels. In agreement with this, we find that monolayers of shrunken PNIPAM particles are compressed more easily than that of swollen PNIPAM particles. The role of electrostatic interactions is further addressed by modifying the concentration of electrolyte, which alters the effective charge but retains the particle size of microgels. We find that screening the effective charge of the microgel has a strong impact on the lateral packing of the monolayer, displacing the compression isotherms to higher normalised areas. Moreover, the displacement correlates with the changes in the effective charge of the microgels induced by the electrolyte. Hence, we prove that beyond the different swelling ratio, electrostatics can modulate the interactions between charged microgel particles at the interface.

Reference: Yang et al. Journal of Molecular Liquids 303 (2020) 112678.

Acknowledgements: This researchwas funded by “Ministerio de Ciencia e Innovación (MICINN), Plan Nacional de Investigación, Desarrollo e Innovación Tecnológica (I + D + i)”, Project RTI2018- 101309-B-C21, European Regional Development Fund (ERDF) and “Consejería de Conocimiento, Investigación y Universidad, Junta de Andalucía”, ref. SOMM17/6105/UGR and SOMM17/6109/UGR.

Recent advances in the coarse-grained simulation of polymer nanogels

Alberto Martín-Molina

Departamento de Física Aplicada, Universidad de Granada, Spain

Abstract

In the last decades, micro- and nanogels have attracted considerable attention due to their versatility and high sensitivity to external stimuli. The availability of this system to control the response is considered to be highly advantageous for their future use in the biomedical field, taking into account their enhanced efficacy and ability to carry and release drugs to the targeted tissue. In this lecture, we present an overview of latest advances in coarse-grained simulations of nanogels. Computer simulations of polyelectrolytes of a few tens of nanometres are nowadays impracticable at atomistic level. [1] This limitation has therefore resulted in the development of coarse-grained models, which reduce the level of detail in the picture of the system but account for the degree of crosslinking and the complex topology of nanogels. In addition, these models can provide valuable information about steric and electrostatic effects on different single-particle properties, such as the swelling behaviour, mass distributions, ionic distributions, effective charge or electrostatic potential. [1] Coarse-grained simulations have also been employed to compute forces between nanogels [2,3] and to calculate the diffusion coefficient of particles in polymer networks. [4]

Interaction between two neutral nanogels (of diameter 2R) at a separation r of the centres of mass

[1] A. Martín-Molina and M. Quesada-Pérez, A Review of Coarse-Grained Simulations of Nanogel and Microgel Particles, J. Mol. Liq. 280, (2019).

[2] S. Ahualli, A. Martín-Molina, J. A. Maroto-Centeno, and M. Quesada-Pérez, Interaction between Ideal Neutral Nanogels: A Monte Carlo Simulation Study, Macromolecules 50, 2229 (2017).

[3] M. Quesada-Pérez, J. A. Maroto-Centeno, A. Martín-Molina, and A. Moncho-Jordá, Direct Determination of Forces between Charged Nanogels through Coarse-Grained Simulations, Phys. Rev. E 97, 042608 (2018).

[4] M. Quesada-Pérez and A. Martín-Molina, Solute Diffusion in Gels: Thirty Years of Simulations, Adv. Colloid Interface Sci. 287, (2021).

Gold nanoparticles bioconjugation: towards a protocolized procedure

Eduardo Méndez

Laboratorio de Biomateriales, Universidad de la República, Uruguay

Abstract

Bioconjugated nanoparticles are widely used in various fields, including analytical biochemistry, clinical testing, and drug delivery. The studies carried out to characterize these particles and the procedures associated with their surface modification were initially framed in the "nano" field, but once the applications were established, quickly jumped to other fields of application. The use of nanoparticles in new fields of research makes it necessary to introduce a strict control of procedures to address very specific aspects that can be found beyond the area of ​​application. The procedure that ranges from the synthesis of gold nanoparticles to obtaining a pure bioconjugate goes through a series of steps that must be controlled to verify compliance. For this, there are a variety of analytical techniques that can be applied, and whose selection is key to meet the desired objective. In this presentation, we will compare the different analytical procedures that can be applied to prepare a protocol that allows the synthesis of gold nanoparticle bioconjugates with adequate homogeneity and stability.

Motion of a self-propelled colloid interacting with a giant lipid vesicle

Antonio Stocco

Institut Charles Sadron, Université de Strasbourg, France

Abstract

Self-propelled colloidal particles either living or artificial, possess original dynamics when interact with other objects like passive particles, interfaces or cell membranes. Interaction of these self-propelled bodies with a biological cell membrane plays a crucial role in many important processes such as viral infections, drug delivery and nano-material toxicity. Here, we experimentally investigate a biologically mimicking system comprising of isolated self-propelled active colloids moving in the neighbourhood of a Giant Unilamellar Vesicle (GUV). We observed a lack of adhesion of the colloidal particles on the GUV membranes in thermal equilibrium. However, when the particle self-propulsion is trigged by the catalytic fuel H₂O₂, the colloid exhibit a persistent hydrodynamic attraction with the GUV giving rise to various phenomena including a persistent orbital motion around the vesicle boundary along with displacement of GUV during the impact dynamics.

Active colloids orbiting giant vesicles, Soft Matter, 2021, doi.org/10.1039/D0SM02183K

Role of Meibomian lipids on the retardation of evaporation of the tear film

Bernardo Yáñez Soto

Cátedras Conacyt – Instituto de Física, Universidad Autónoma de San Luis Potosí, Mexico

Abstract

Dry eye disease (DED) is a group of pathologies leading to ocular surface damage. Among other burdens, DED increases healthcare costs, and reduces of the quality of life of sufferers. DED occurs when the fluid covering the surface of the eye, or tear film, loses its homeostasis. Specifically, in evaporative dry eye, the evaporation of the tear film is higher than the natural renewal of tears. One of the means the eye regulates the evaporation is through the Tear Film Lipid Layer (TFLL) a thin layer of lipid produced mainly by the Meibomian glands, which are located inside the lids. The TFLL has an approximate composition of 60-70% nonpolar lipids (wax esters, cholesterol and cholesterol esters), and 15% polar lipids (phospholipids and glycolipids). The thickness of the TFLL varies depending on the eye aperture, and values between 32-200 nm have been reported, indicating the existence of a duplex layer. The functions attributed to the TFLL include maintaining the lid margin in a hydrophobic state to avoid tear overflow, the lowering of the tear surface tension, and the retardation of evaporation.

There has been a number of experimental studies trying to measure the specific influence of the TFLL on evaporation, but the results have been unimpressive and equivocal. We propose two different systems to quantify the influence of the TFLL on the evaporation of the tear film. The first system consist on the measurement of the volume of pendant drops, and the second systems relies on the evaporation induced by non-axisymmetric contact points. For the determination of the evaporation we used Meibomian lipids obtained from healthy controls and from patients suffering from varios Meibomian gland pathologies, and found that the evaporation of fluids covered with Meibomial lipid films can be as low as 50% of pure water.

The functions attributed to the TFLL require the formation of a stable, continuous layer that resist the compression and expansion cycles due to blinking. We have measured the bulk rheology of Meibomian lipids cases and controls, using a Quartz Microbalance with Dissipation, as well as the surface rheology of Meibomian lipid layers by the method of oscillation of a pending drop. This study may help in the development of novel therapeutics for the treatment of dry eye syndrome.

Membrane-peptides interaction: solid or fluid phases, liquid-disordered or liquid-ordered phases, hopanoids or sterols.

Natalia Wilke

Centro de Investigaciones en Química Biológica de Córdoba, Universidad Nacional de Córdoba, Argentina

Abstract

Cellular membranes regulate lateral diffusion of species, compartmentalization and permeability. Despite it has been shown that the organisms adapt the lipid composition of their membranes in order to maintain them in a mainly fluid state, several studies performed in plasma and internal membranes point to the existence of regions with different composition, leading to different mechanical properties. While proteins have been related with solid docks, sterols are accepted as liquid-ordered phase state inducers. Thus, the current model for membranes is a patchwork-like surface, with the different regions being highly variable both, in size and in time.

On the other hand, molecules such as peptides that interact with membranes may have different affinities with different membrane compositions, compaction, and fluidity. As a consequence of the patchwork-like character of the membrane, membrane regions with a broad spectrum of properties are available for the interaction with a soluble peptide. Thus, it is important to know how the peptide-membrane interaction depends on membrane properties, and also what happens with these membranes after the interaction occurred.

With this in mind, we studied the interaction and consequent effect of cationic peptides with membranes in gel and in fluid phase states. In this last membranes, the composition was varied in order to test liquid-disordered and liquid-ordered phase. Furthermore, liquid-ordered phases were induced with cholesterol or diplopterol, which is a sterol-surrogate hopanoid.

The results indicate that the phase state is an important factor for peptide adsorption, incorporation into the membrane and consequent translocation across the membrane. Gel-like membranes showed a good interaction with a Cell Penetration Peptide (CPP). The CR9K peptide adsorbed, incorporated and crossed these membranes. However, membrane lysis was observed at low peptide concentrations. On the contrary, liquid-ordered membranes did not incorporate this peptide, but it remained adsorbed at the membrane surface. Finally, a good adsorption, penetration and translocation was observed when this peptide was added to membranes in a liquid-disordered phase state. After the CPP addition, membrane shape fluctuations increased and the membrane resistance upon curvature changes resulted weaker.

Finally, a peptide with higher membrane affinity than CR9K was exposed to liquid-ordered membranes. MP1, a peptide with demonstrated antimicrobial character, was added to membranes with cholesterol or diplopterol. This peptide adsorbed, incorporated and crossed these membranes at low concentrations, and had lytic properties at high concentrations. However, the affinity and general interaction properties depended on which was the liquid-ordered phase inducer. Thus, besides the membrane phase state, there is an additional regulation of the phenomena mediated by the membrane composition.

Contributed Talks

C1. Visualizing early-stage coacervate formation with a phase field model for mixed polyelectrolyte solutions. Rajarshi Sengupta, Chelsea Edwards, Kris Delaney, Matt Helgeson, Glenn Fredrickson. Chemical Engineering, UC Santa Barbara (USA).

C2. What can we learn about amphiphile-membrane interaction from model lipid membranes? Maria Laura Fanani, Natalia Nocelli and Yenisleidy de las Mercedes Zulueta Díaz. Facultad de Ciencias Químicas, Universidad Nacional de Córdoba (Argentina).

C3. Gelation of Amphiphilic Spherical Particles in a Hydrophobic Medium. Denise Chirinos-Flores, Rodrigo Sánchez, Pedro Díaz-Leyva, Anna Kozina. Insitute of Chemistry, National Autonomous University of Mexico (Mexico).

C4. Optical Translational and Rotational Microrheology of Polymer Solutions and Gels. Carlos Gutiérrez-Sosa, Rodrigo Sánchez, Anna Kozina, Pedro Díaz-Leyva. Universidad Autónoma Metropolitana - Iztapalapa (Mexico).

C5. Caging-uncaging transitions due to the overlap of excluded volume. Adrián Huerta. Universidad Veracruzana (Mexico).

C6. Synthesis of a surfactant based on oleic acid and L-cysteine. Marco Vizcarra-Pacheco, María Ley-Flores, Mizrahim Matrecitos-Burruel, Ricardo López-Esparza, Daniel Fernández-Quiroz, Armando Lucero-Acuña, Paul Zavala-Rivera. Universidad de Sonora (Mexico).

C7. Surface-induced self-assembly of amphiphic block copolymer bilayers. Flávia Mesquita Cabrini, Alliny Ferreira Naves, Martin Fauquignon, Ludovic Belhomme, Christophe Schatz, Jean-Paul Chapel. Centre de Recherche Paul Pascal (France).

C8. Self-assembled micropatterns as test structures for surface potential mapping of biomolecules. Leonardo I. Ruiz-Ortega, Iván Ortega-Blake. Instituto de Ciencias Físicas de la Universidad Nacional Autónoma de México (Mexico).

C9. SERS detection and nano-bio interface of microorganisms using Concanavalin-A encapsulated gold nanoparticles. Ravichandran Manisekaran, Mariana Vázquez Ibarra, Genoveva Hernández Padrón, Luz M. López Marín. LII-ENES, Leon-UNAM (Mexico).

C10. Spontaneous Pattern Growth on Chocolate Surface: Simulations and Experiments. José Jorge Delgado García, Claudia Ferreiro-Córdova, Alejandro Gil-Villegas. Universidad de Guanajuato (Mexico).

C11. Composites 3D printed of nanocellulose gels derived from Mexican biomass: removal of lead (II) in water. Tania E. Lara-Ceniceros, Elizabeth Hernández-Francisco, José Bonilla-Cruz, Rigoberto C. Advíncula. CIMAV Monterrey (Mexico).

C12. Flexible water. Raúl Fuentes-Azcatl. Universidad Autónoma Metropolitana (Mexico).

C13. Interfacial Absorption Behaviors of Polyelectrolyte Complexes Precipitate/Coacervate. Hongwei Li, Jean-Paul Chapel, Christophe Schatz. Université de Bordeaux – CNRS (France).

C14. The triple Leidenfrost effect: how to prevent coalescence of miscible droplets on a hot plate. Felipe Pacheco Vázquez, Jhayson Palacio Rangel. Benemérita Universidad Autónoma de Puebla (Mexico).

C15. Texture analysis of dried droplets to detect adulteration in medicines. Yojana J. P. Carreon, Jorge Gonzalez-Gutierrez. UNAM – ICAT (Mexico).

C16. Study of electrical properties of red blood cells. Daniela Gallardo-Galaviz, Carla Angulo-Rojo, Carmen L. Moraila-Martinez. Departamento de Ingeniería Física, Campus León, Universidad de Guanajuato (Mexico).

C17. Aqueous-Organic Phase Transfer of Iron Oxide@ Iron Carbide Nanoparticles Using Amide-Amine Modified Oleic Acid. Anya Arguelles-Pesqueira, Paul Zavala-Rivera, Armando Lucero-Acuña, Patricia Guerrero-German, Aaron Rosas Durazo, Ramon Moreno-Corral, Judith Tánori. Universidad de Sonora (Mexico).

C18. Colloids and Additive Manufacturing. Adriana Siqueiros-Pérez, Alfredo E. Cervantes-Martínez. Instituto Tecnológigo de Sonora – Campus Guaymas (Mexico).

Virtual Posters

P1. Reproducible nanobubble generation: towards an enhanced thermoacoustic energy conversion for theranostics applications. J. Lombard, J. Lam, F. Detcheverry, T. Biben, M. Orrit, S. Merabia. Departamento de Física y Química Teórica Facultad de Química UNAM, CEMES CNRS and Université de Toulouse, Institut Lumière Matière Université Lyon 1 CNRS, Institut Lumière Matière Université Lyon 1 CNRS, Leiden Institute of Physics Universiteit Leiden, Institut Lumière Matière Université Lyon 1 CNRS.

P2. Investigation of anomalous dynamics of water-in-oil microemulsions by neutron scattering. Tanvi Sheth, Mengwen Zhang, Serena Seshadri, Matthew E. Helgeson. University of California Santa Barbara.

P3. Withdrawn.

P4. Diffusion of colloids in fractal-like structures. Román Perdomo-Pérez, Ramón Castañeda-Priego. División de Ciencias e Ingenierías, Universidad de Guanajuato.

P5. Mapping the square-well and square-shoulder potentials onto continuous and differentiable potentials using the second virial coefficient criterion. Miguel Ángel Sandoval Puentes, Alexis Torres Carbajal, Ramón Castañeda Priego. División de Ciencias e Ingenierı́as, Universidad de Guanajuato, Instituto de Fı́sica “Manuel Sandoval Vallarta”, Universidad Autónoma de San Luis Potosı́, División de Ciencias e Ingenierı́as, Universidad de Guanajuato.

P6. Orientational dynamics driven by an external field in multipolar colloids. Erwin Ramírez Solano, Honorina Ruiz Estrada, Roberto Ramírez Sánchez. Faculty of Physical and Mathematical Sciences at BUAP.

P7. Propiedades dinámicas de partículas Brownianas activas y no activas en campos externos. Ana Laura Merino Díaz, Roberto Ramírez Sánchez, Erwin Ramírez Solano. Facultad de Ciencias Físico Matemáticas, BUAP.

P8. Spirals, rings, helices, and layered structures in Monte Carlo simulations of confined colloids. Sebastián Jiménez-Millán, Saúl Iván Hernández, Consuelo García-Alcántara, Abelardo Ramírez-Hérnandez, Edward Sambriski. Centro de Física Aplicada y Tecnología Avanzada-UNAM, Unidad Multidisciplinaria de Docencia e Investigación-Juriquilla-UNAM, Unidad Multidisciplinaria de Docencia e Investigación-Juriquilla, Department of Chemistry-Delaware Valley University, Department of Physics and Astronomy-The University of Texas at San Antonio.

P9. Transport properties in short-range attractive colloidal systems under gravitational fields. Jaime Martínez-Rivera, Ramón Castañeda-Priego. División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato. Loma del Bosque 103, Colonia Lomas del Campestre, 37150 León, Guanajuato, México.

P10. Ring-like colloidal deposits formed at uniformly-driven contact lines in saturated atmosphere. Effect of the particle electric charge. Jesús Gerardo Guerrero Félix, Carmen Lucía Moraila Martínez, Miguel Ángel Rodríguez Valverde, Miguel Cabrerizo Vílchez. Facultad de Biología de la Universidad Autónoma de Sinaloa, Parque de Innovación Tecnológica de la Universidad Autónoma de Sinaloa, Departamento de Física Aplicada de la Universidad de Granada España.

P11. A Magnetic Nanoparticle Microfluidic Trap. Reynoso-Hernandez K.B., Guevara-Pantoja P.E., Caballero-Robledo G.A. Cinvestav, Monterrey.

P12. Analysis of the effect of curvature and confinement on an active particle using a nonvibrating granular system. A. Escobar, F. Donado. Instituto de Ciencias Básicas e Ingeniería de la Universidad Autónoma del Estado de Hidalgo-AAMF.

P13. Withdrawn.

P14. Long-term diffusion of a model protein in the spherical electrical double layer. Daniela Perez Guerrero [1], Guillermo Ivan Guerrero-Garcia [2]. [1] Posgrado en Ciencias Interdisciplinarias, Institute of Physics, UASLP, San Luis Potosi, Mexico, [2] Faculty of Sciences, UASLP, Av. Chapultepec 1570, 78210, San Luis Potosi, Mexico.

P15. On the non-dominance of counterions in the 1:z planar electrical double layer of point ions. Jonathan Josué Elisea-Espinoza, Enrique González-Tovar, José Adrián Martínez-González, César Gabriel Galván Peña, Guillermo Iván Guerrero-García. Institute of Physics UASLP, Institute of Physics UASLP, Faculty of Sciences UASLP, Faculty of Sciences UASLP, Faculty of Sciences UASLP.

P16. Effective charge of PNIPAM microgels determined by conductivity measurements. Antelmo Lozano-Martínez, Adriana Campos-Ramírez, Mónica Ledesma-Motolinía, Luis Rojas-Ocho, Catalina Haro-Pérez. Departamento de Ciencias Básicas (UAM-Azcapotzalco), Departamento de Ciencias Básicas (UAM-Azcapotzalco), Departamento de Ciencias Básicas (UAM-Azcapotzalco), Departamento de Física (Cinvestav-IPN), Departamento de Ciencias Básicas (UAM-Azcapotzalco).

P17. Compaction analysis of asphalt concrete with or without additives by X-ray computed tomography. Anyi M. Tacumá Garzón, Jorge Raul Cerna Cortez, César Márquez Beltrán. Posgrado en Ciencias Químicas, Facultad en Ciencias Químicas, Instituto de Física Benemérita Universidad Autónoma de Puebla.

P18. Study of the structural characteristics of tiny crystals formed in a two-dimensional granular system as a function of effective temperature. Mónica Ledesma Motolinía, José Luis Carrillo Estrada, Fernando Donado Pérez. Instituto de Física "Ing. Luis Rivera Terrazas", Instituto de Física "Ing. Luis Rivera Terrazas", Universidad Autónoma del Estado de Hidalgo.

P19. Electrokinetic study for the characterization of the formed elements of the blood. Daniela Gallardo Galaviz, Carmen Lucía Moraila Martínez. Universidad Autónoma de Sinaloa, Universidad de Guanajuato.

P20. Characterization of the desert beetle Eleodes eschscholtzii’s elytra hydrophobicity associated with a moisture gradient between two locations in the Sonoran Desert, Mexico. Luis Eduardo Tellechea Robles¹, Amir Darío Maldonado Arce², Rodrigo Méndez Alonzo³, Francisco Elizandro Molina Freaner⁴. Universidad de Sonora. 1) Departamento de Investigación en Polímeros y Materiales, Universidad de Sonora), 2) Departamento de Física, Universidad de Sonora, 3) Departamento de Biología de la Conservación, CICESE, 4) UNAM, Estación Regional del Noroeste.