Estimation of casein micelles' surface energy by means of contact angle measurements

1989 ◽  
Vol 56 (2) ◽  
pp. 223-234 ◽  
Author(s):  
Michel Britten ◽  
Marcel Boulet ◽  
Paul Paquin
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Potential Energy ◽  
Short Range ◽  
Casein Micelle ◽  
Casein Micelles ◽  
Surface Energies ◽  
Angle Measurements ◽  
Heat Treated ◽  
Contact Angle Measurements

SummaryThe surface energies of highly hydrated casein micelle layers isolated from variously pretreated skim milks have been determined by means of contact angle measurements. The long range Lifshitz-Van der Waals (LW) and the short range hydrogen bonding (SR) components of surface energy were determined using α-bromonaphthalene and water for contact angle measurements. Casein micelles isolated from untreated and heat treated milks showed similar surface energy values of about 63·5 mJ.m-2 with an LW component of 19·2 mJ.m-2 and an SR component of 44·3 mJ.m-2. The calculated attraction potential energy was − 0·7 mJ.m-2. Casein micelles isolated from renneted milk showed a surface energy of 33·0 mJ.m-2 with an LW component of 30·7 mJ.m-2 and an SR component of 2·3 mJ.m-2. The attraction potential energy of renneted micelles was nearly two orders of magnitude higher than those of micelles from other milks ( − 63·3 mJ.m-2). The SR component of interfacial energy accounted for 98% of this attraction potential. The importance of attractive forces in relation to casein micelle stability is discussed.

Surface Energy and Wetting Behaviour of Plasma Etched Porous SiCOH Surfaces and Plasma Etch Residue Cleaning Solutions

2009 ◽  
Vol 145-146 ◽  
pp. 319-322 ◽  
Author(s):  
Nicole Ahner ◽  
Matthias Schaller ◽  
Christin Bartsch ◽  
Eugene Baryschpolec ◽  
Stefan E. Schulz
Keyword(s):  
Surface Energy ◽  
Dielectric Materials ◽  
Solid Surfaces ◽  
Plasma Etch ◽  
Surface Energies ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Additional Process ◽  
Low K ◽  
Etch Residue

The removal of plasma etch residues by wet cleaning is an alternative or additional process to plasma processes, which are known to degrade low-k and ultralow-k dielectric materials. Besides Cu/low-k compatibility wetting is an important issue for wet cleaning. Surface energy of solid and liquid is the key to understand the wetting behaviour. In this study we examined the energetic character of plasma etched/stripped solid surfaces, etch polymers and several cleaning solutions by contact angle measurements. The results show, that variations of the etching process can heavily change the energetic character of the solid. Calculating the surface energies of solid and liquid provides the possibility to make a prediction if a cleaning liquid will wet the surface which has to be cleaned.

scholarly journals Tailoring the Composition and Properties of Sprayed CuSbS2Thin Films by Using Polymeric Additives

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Ionut Popovici ◽  
Anca Duta
Keyword(s):  
Thin Films ◽  
Contact Angle ◽  
Ir Spectroscopy ◽  
Surface Energy ◽  
Hydrophilic Polymers ◽  
Film Morphology ◽  
Angle Measurements ◽  
Polymeric Additives ◽  
Contact Angle Measurements ◽  
Spray Pyrolysis Deposition

CuSbS2thin films were obtained by spray pyrolysis deposition, using polymeric additives for controlling the surface properties and film’s composition. Ternary crystalline chalcostibite compounds have been obtained without any postdeposition treatments. XRD spectra and IR spectroscopy were used to characterize films composition and interactions between components. Films morphology and surface energy were investigated using AFM microscopy and contact angle measurements. Hydrophobic and hydrophilic polymers strongly influence the composition and film morphology.

scholarly journals Cell Morphology on Poly(methyl methacrylate) Microstructures as Function of Surface Energy

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Matthias Katschnig ◽  
Boris Maroh ◽  
Natascha Andraschek ◽  
Sandra Schlögl ◽  
Ulrike Zefferer ◽  
...  
Keyword(s):  
Contact Angle ◽  
Cell Adhesion ◽  
Surface Energy ◽  
Methyl Methacrylate ◽  
Cell Elongation ◽  
Cell Phenotype ◽  
Critical Surface ◽  
Poly Methyl Methacrylate ◽  
Angle Measurements ◽  
Contact Angle Measurements

Whilst the significance of substrate topography as a regulator of cell function is well established, a systematic analysis of the principles underlying this is still unavailable. Here we evaluate the hypothesis that surface energy plays a decisive role in substrate-mediated modulation of cell phenotype by evaluation of cell behaviour on synthetic microstructures exhibiting pronounced differences in surface energy. These microstructures, specifically cubes and walls, were fabricated from a biocompatible base polymer, poly(methyl methacrylate), by variotherm injection molding. The dimensions of the cubes were 1 μm x 1 μm x 1 μm (height x width x length) with a periodicity of 1:1 and 1:5 and the dimensions of the walls 1 μm x 1 μm x 15 mm (height x width x length) with a periodicity of 1:1 and 1:5. Mold inserts were made by lithography and electroplating. The surface energy of the resultant microstructures was determined by static contact angle measurements. Light scanning microscopy of the morphology of NT2/D1 and MC3T3-E1 preosteoblast cells cultured on structured PMMA samples in both cases revealed a profound surface energy dependence. “Walls” appeared to promote significant cell elongation, whilst a lack of cell adhesion was observed on “cubes” with the lowest periodicity. Contact angle measurements on walls revealed enhanced surface energy anisotropy (55 mN/m max., 10 mN/m min.) causing a lengthwise spreading of the test liquid droplet, similar to cell elongation. Surface energy measurements for cubes revealed increased isotropic hydrophobicity (87° max., H2O). A critical water contact angle of ≤ 80° appears to be necessary for adequate cell adhesion. A “switch” for cell adhesion and subsequently cell growth could therefore be applied by, for example, adjusting the periodicity of hydrophobic structures. In summary cell elongation on walls and a critical surface energy level for cell adhesion could be produced for NT2/D1 and MC3T3-E1 cells by symmetrical and asymmetrical energy barrier levels. We, furthermore, propose a water-drop model providing a common physicochemical cause regarding similar cell/droplet geometries and cell adhesion on the investigated microstructures.

Surface Energy and Capillary Pressure

2019 ◽  
pp. 110-139
Author(s):  
C. Mathew Mate ◽  
Robert W. Carpick
Keyword(s):  
Surface Energy ◽  
Capillary Pressure ◽  
Capillary Condensation ◽  
Solid Surfaces ◽  
Work Of Adhesion ◽  
Liquid Droplets ◽  
Surface Energies ◽  
Angle Measurements ◽  
Measuring Surface ◽  
Contact Angle Measurements

The energies associated with surfaces—surface energy, interfacial energy, surface tension, and work of adhesion—drive many surface and interfacial phenomena including tribological ones such as adhesion and friction. This chapter discusses the physical origins of surface energies for liquids and solids, and how the concepts of capillary pressure, capillary condensation, wetting, and work of adhesion are derived from surface energy. Further, this chapter covers the different methods for measuring surface energies, including the most common method for solid surfaces: contact angle measurements of liquid droplets on surfaces. This chapter also introduces how surface energies and surface tensions lead to adhesion and adhesion hysteresis between contacting surfaces, which is followed up in the subsequent chapters on surface forces.

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