scholarly journals THE WEIGHT OF A FALLING DROP AND THE LAWS OF TATE. IV. THE STANDARDIZATION OF A TIP; AND THE CALCULATION OF THE SURFACE TENSION AND MOLECULAR WEIGHT OF A LIQUID FROM THE WEIGHT OF ITS FALLING DROP.

1911 ◽  
Vol 33 (5) ◽  
pp. 643-657
Author(s):  
J. Livingston R. Morgan
Keyword(s):  
Molecular Weight ◽  
Surface Tension

scholarly journals Average molecular weight of surfactants in aerosols

2007 ◽  
Vol 7 (5) ◽  
pp. 13805-13838 ◽  
Author(s):  
M. T. Latif ◽  
P. Brimblecombe
Keyword(s):  
Molecular Weight ◽  
Surface Tension ◽  
Atmospheric Aerosols ◽  
Average Molecular Weight ◽  
Molecular Size ◽  
Weight Fraction ◽  
Ozone Exposure ◽  
Before And After ◽  
Fine Mode ◽  
Active Substances

Abstract. Surfactants in atmospheric aerosols determined as methylene blue active substances (MBAS) and ethyl violet active substances (EVAS). The MBAS and EVAS concentrations can be correlated with surface tension as determined by pendant drop analysis. The effect of surface tension was more clearly indicated in fine mode aerosol extracts. The concentration of MBAS and EVAS was determined before and after ultrafiltration analysis using AMICON centrifuge tubes that define a 5000 Da (5 K Da) nominal molecular weight fraction. Overall, MBAS and to a greater extent EVAS predominates in fraction with molecular weight below 5 K Da. In case of aerosols collected in Malaysia the higher molecular fractions tended to be a more predominant. The MBAS and EVAS are correlated with yellow to brown colours in aerosol extracts. Further experiments showed possible sources of surfactants (e.g. petrol soot, diesel soot) in atmospheric aerosols to yield material having molecular size below 5 K Da except for humic acid. The concentration of surfactants from these sources increased after ozone exposure and for humic acids it also general included smaller molecular weight surfactants.

Surface Tension as a Function of Molecular Weight of Protonated Free and Conjugated Dihydroxy Bile Acids

1986 ◽  
Vol 71 (s15) ◽  
pp. 72P-72P
Author(s):  
C O Mills ◽  
G H Martin ◽  
E Elias
Keyword(s):  
Molecular Weight ◽  
Surface Tension ◽  
Bile Acids

The Surface Tension of Rubber Solutions

1931 ◽  
Vol 4 (3) ◽  
pp. 354-360
Author(s):  
G. W. Shacklock
Keyword(s):  
Molecular Structure ◽  
Molecular Weight ◽  
Surface Tension ◽  
Benzene Solution ◽  
Rubber Particle ◽  
Mechanical Action ◽  
The Past ◽  
Pure Product ◽  
Simple Molecules ◽  
Improved Methods

Abstract During the past few years much attention has been paid to the constitution of raw rubber. The much improved methods of production of plantation rubber have resulted in a reasonably pure product available for investigation, and chemical analysis undoubtedly shows an empirical formula of C5H8 for the hydrocarbon. From this point onward, knowledge becomes less certain. Osmotic pressure and molecular weight measurements give no confirmation of a simple molecular structure, but show, in benzene solution, a behavior comparable with that of colloids. This is supported by experiments on swelling and viscosity, and by ultramicroscopic examination, all of which lead to the conclusion that rubber is a lyophilic colloid. Hence arose the concept that the rubber particle is a polymer of simple molecules of formula C5H8 (possibly isoprene), such a structure being in agreement with the production of rubber-like substances by the action of sodium upon isoprene and butadiene (Harries, Annalen, 395, 211 (1912)). The decrease in viscosity of a rubber solution with increasing periods of mastication of the rubber is hence regarded as a measure of depolymerization due to mechanical action; the increased ease of solution after mastication is confirmatory evidence.

Molecular weight dependence and end-group effects on the surface tension of poly(dimethylsiloxane)

1993 ◽  
Vol 26 (12) ◽  
pp. 3069-3074 ◽  
Author(s):  
Claire Jalbert ◽  
Jeffrey T. Koberstein ◽  
Iskender Yilgor ◽  
Paula Gallagher ◽  
Val Krukonis
Keyword(s):  
Molecular Weight ◽  
Surface Tension ◽  
Molecular Weight Dependence ◽  
End Group ◽  
Group Effects

scholarly journals ADSORPTION AND DILATIONAL RHEOLOGICAL PROPERTIES OF CHITOSAN LACTATE AT THE LIQUID-GAS INTERFACE

2020 ◽  
pp. 816-826
Author(s):  
Анна Игоревна Ковтун
Keyword(s):  
Molecular Weight ◽  
Surface Tension ◽  
Surface Elasticity ◽  
Rheological Characteristics ◽  
Drop Shape ◽  
Equilibrium Surface Tension ◽  
Viscoelastic Modulus ◽  
Surface Active ◽  
Adsorption Layers ◽  
Chitosan Lactate

Методом формы осциллирующей капли исследованы адсорбционные и дилатационные реологические характеристики (модуль упругости и вязкости) лактата хитозана на границе раздела жидкость - газ. Определены зависимости динамического и равновесного поверхностного натяжения от концентрации лактата хитозана в растворе. Установлено, что полученные зависимости сходны с таковыми для поверхностноактивных высокомолекулярных соединений. Изучены зависимости поверхностных упругости и вязкости лактата хитозана от частоты осцилляций и концентрации. Показано, что лактат хитозана способен образовывать упругие адсорбционные слои со значениями модуля вязкоупругости сопоставимыми для биополимеров белковой природы. The adsorption and dilatational rheological characteristics (the elasticity and viscosity modulus) of chitosan lactate at the liquid-gas interface are investigated by the oscillating drop shape method. The dependences of the dynamic and equilibrium surface tension on the concentration of chitosan lactate in solution have been determined. It was found that the dependences obtained are similar to those for surface-active high-molecular weight compounds. The dependences of the surface elasticity and viscosity of chitosan lactate on the oscillation frequency and concentration have been studied. It has been shown that chitosan lactate is capable of forming elastic adsorption layers with the values of the viscoelastic modulus comparable to that of protein biopolymers.

scholarly journals Microbial Biosurfactants as Key Multifunctional Ingredients for Sustainable Cosmetics

Cosmetics ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 46 ◽  
Author(s):  
Hamid-Reza Ahmadi-Ashtiani ◽  
Anna Baldisserotto ◽  
Elena Cesa ◽  
Stefano Manfredini ◽  
Hossein Sedghi Zadeh ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Surface Tension ◽  
Environmental Impact ◽  
Infectious Diseases ◽  
Homogeneous Mixture ◽  
Present Review ◽  
Main Application ◽  
Polar Head ◽  
External Threats

A polar head and an apolar tail chemically characterize surfactants, they show different properties and are categorized by different factors such as head charge and molecular weight. They work by reducing the surface tension between oil and water phases to facilitate the formation of one homogeneous mixture. In this respect, they represent unavoidable ingredients, their main application is in the production of detergents, one of if not the most important categories of cosmetics. Their role is very important, it should be remembered that it was precisely soaps and hygiene that defeated the main infectious diseases at the beginning of the last century. Due to their positive environmental impact, the potential uses of microbial sourced surfactants are actively investigated. These compounds are produced with different mechanisms by microorganisms in the aims to defend themselves from external threats, to improve the mobility in the environment, etc. In the cosmetic field, biosurfactants, restricted in the present work to those described above, can carry high advantages, in comparison to traditional surfactants, especially in the field of sustainable and safer approaches. Besiede this, costs still remain an obsatcle to their diffusion; in this regard, exploration of possible multifunctional actions could help to contain application costs. To highlight their features and possible multifunctional role, on the light of specific biological profiles yet underestimated, we have approached the present review work.

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