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LA GRAMMATICA DI ENGLISH GRATIS IN VERSIONE MOBILE   INFORMATIVA PRIVACY

  NUOVA SEZIONE ELINGUE

 

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WIKIBOOKS
DISPONIBILI
?????????

ART
- Great Painters
BUSINESS&LAW
- Accounting
- Fundamentals of Law
- Marketing
- Shorthand
CARS
- Concept Cars
GAMES&SPORT
- Videogames
- The World of Sports

COMPUTER TECHNOLOGY
- Blogs
- Free Software
- Google
- My Computer

- PHP Language and Applications
- Wikipedia
- Windows Vista

EDUCATION
- Education
LITERATURE
- Masterpieces of English Literature
LINGUISTICS
- American English

- English Dictionaries
- The English Language

MEDICINE
- Medical Emergencies
- The Theory of Memory
MUSIC&DANCE
- The Beatles
- Dances
- Microphones
- Musical Notation
- Music Instruments
SCIENCE
- Batteries
- Nanotechnology
LIFESTYLE
- Cosmetics
- Diets
- Vegetarianism and Veganism
TRADITIONS
- Christmas Traditions
NATURE
- Animals

- Fruits And Vegetables



ARTICLES IN THE BOOK

  1. Academy Award for Makeup
  2. Aloe
  3. Alpha hydroxy acid
  4. Anti-aging cream
  5. Arenation
  6. Aromatherapy
  7. Artistry
  8. Astringent
  9. Beauty
  10. Beauty mark
  11. Beauty salon
  12. Camouflage Cosmetic
  13. Campaign for Safe Cosmetics
  14. Carnauba wax
  15. Castor oil
  16. Chanel No. 5
  17. Chemical peel
  18. Christian Dior
  19. Clinique
  20. Concealer
  21. Corpse paint
  22. Cosmeceutical
  23. Cosmetic advertising
  24. Cosmetics
  25. Cosmetology
  26. Creed
  27. Dermabrasion
  28. Dermatology
  29. Destination spa
  30. Eau de cologne
  31. Electrology
  32. Elizabeth Arden
  33. Essential oil
  34. Estée Lauder
  35. Estée Lauder Companies
  36. Estée Lauder pleasures
  37. Exfoliation
  38. Eye liner
  39. Eyeshadow
  40. Facial toning
  41. Glitter
  42. Glycerol
  43. Guerlain
  44. Hair
  45. Hair extension
  46. Helena Rubinstein
  47. Hermès
  48. History of cosmetics
  49. History of Perfume
  50. Hot tub
  51. INCI
  52. Jojoba oil
  53. Kohl
  54. Lancome
  55. Lip gloss
  56. Lip plumper
  57. Lipstick
  58. List of cosmetic ingredients
  59. L'Oréal
  60. Makeover
  61. Make-up artist
  62. Manicure
  63. Mascara
  64. Max Factor
  65. Max Factor, Sr.
  66. Maybelline
  67. Microdermabrasion
  68. Nail polish
  69. Natural skin care
  70. Noxzema
  71. Olay
  72. Pedicure
  73. Perfume
  74. Perfume bottles
  75. Permanent makeup
  76. Permanent wave
  77. Plastic surgeons
  78. Retinol
  79. Revlon
  80. Rimmel
  81. Rouge
  82. Shampoo
  83. Shaving
  84. Shaving cream
  85. Shea butter
  86. Shiseido
  87. Shower gel
  88. Skin Deep
  89. Skin whitening
  90. Soap
  91. Sunless tanning
  92. Sun tanning
  93. Surfactant
  94. Talcum powder
  95. Tanning bed
  96. Tanning lamp
  97. Thanaka
  98. The Body Shop
  99. Waxing
  100. Wella
  101. What Not to Wear

 


 

 
CONDIZIONI DI USO DI QUESTO SITO
L'utente può utilizzare il nostro sito solo se comprende e accetta quanto segue:

  • Le risorse linguistiche gratuite presentate in questo sito si possono utilizzare esclusivamente per uso personale e non commerciale con tassativa esclusione di ogni condivisione comunque effettuata. Tutti i diritti sono riservati. La riproduzione anche parziale è vietata senza autorizzazione scritta.
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  • L'utente, inoltre, accetta di tenerci indenni da qualsiasi tipo di responsabilità per l'uso - ed eventuali conseguenze di esso - degli esercizi e delle informazioni linguistiche e grammaticali contenute sul siti. Le risposte grammaticali sono infatti improntate ad un criterio di praticità e pragmaticità più che ad una completezza ed esaustività che finirebbe per frastornare, per l'eccesso di informazione fornita, il nostro utente. La segnalazione di eventuali errori è gradita e darà luogo ad una immediata rettifica.

     

    ENGLISHGRATIS.COM è un sito personale di
    Roberto Casiraghi e Crystal Jones
    email: robertocasiraghi at iol punto it

    Roberto Casiraghi           
    INFORMATIVA SULLA PRIVACY              Crystal Jones


    Siti amici:  Lonweb Daisy Stories English4Life Scuolitalia
    Sito segnalato da INGLESE.IT

 
 



COSMETICS
This article is from:
http://en.wikipedia.org/wiki/Surfactant

All text is available under the terms of the GNU Free Documentation License: http://en.wikipedia.org/wiki/Wikipedia:Text_of_the_GNU_Free_Documentation_License 

Surfactant

From Wikipedia, the free encyclopedia

 
This article is about surfactants in general. For the compound produced by alveolar cells, see pulmonary surfactant.

Surfactants are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids.

Etymology

The term surfactant is a blend of "surface active agent". Surfactants are usually organic compounds that are amphiphilic, meaning they contain both hydrophobic groups (their "tails") and hydrophilic groups (their "heads"). Therefore, they are soluble in both organic solvents and water. The term surfactant was coined by Antara Products in 1950.


In Index Medicus and the United States National Library of Medicine, "surfactant" is reserved for the meaning pulmonary surfactant (see "alveoli" link below). For the more general meaning, "surface active agent" is the heading.

Operation and effects

A micelle - the lipophilic ends of the surfactant molecules dissolve in the oil, while the hydrophilic charged ends remain outside, shielding the rest of the hydrophobic micelle
A micelle - the lipophilic ends of the surfactant molecules dissolve in the oil, while the hydrophilic charged ends remain outside, shielding the rest of the hydrophobic micelle

Surfactants reduce the surface tension of water by adsorbing at the liquid-gas interface. They also reduce the interfacial tension between oil and water by adsorbing at the liquid-liquid interface. Many surfactants can also assemble in the bulk solution into aggregates. Some of these aggregates are known as micelles. The concentration at which surfactants begin to form micelles is known as the critical micelle concentration or CMC. When micelles form in water, their tails form a core that is like an oil droplet, and their (ionic/polar) heads form an outer shell that maintains favorable contact with water. When surfactants assemble in oil, the aggregate is referred to as a reverse micelle. In a reverse micelle, the heads are in the core and the tails maintain favorable contact with oil.

Surfactants are also often classified into four primary groups; anionic, cationic, non-ionic, and zwitterionic (dual charge).

Thermodynamics of the surfactant systems are of great importance, theoretically and practically. This is because surfactant systems represent systems between ordered and disordered states of matter. Surfactant solutions may contain an ordered phase (micelles) and a disordered phase (free surfactant molecules and/or ions in the solution).

Ordinary washing up detergent, for example, will promote water penetration in soil, but the effect would only last a few days (although many standard laundry detergent powders contain levels of chemicals such as sodium and boron, which can be damaging to plants, so these should not be applied to soils). Commercial soil wetting agents will continue to work for a considerable period, but they will eventually be degraded by soil micro-organisms. They can, however, interfere with the life-cycles of some aquatic organisms, so care should be taken to prevent run-off of these products into streams, and excess product should not be washed down gutters.

Applications

Surfactants play an important role in many practical applications and products, including:

  • Detergents
  • Fabric softener
  • Emulsifiers
  • Paints
  • Adhesives
  • Inks
  • Alveoli
  • Wetting
  • Ski Wax
  • Snowboard Wax
  • Foaming
  • Defoaming
  • Laxatives
  • Agrochemical formulations
    • Herbicides
    • Insecticides
  • Quantum dot coating
  • Biocides (Sanitizers)
  • Hair Conditioners (after shampoo)
  • Spermicide (Nonoxynol 9)

Classification

A surfactant can be classified by the presence of formally charged groups in its head. A nonionic surfactant has no charge groups in its head. The head of an ionic surfactant carries a net charge. If the charge is negative, the surfactant is more specifically called anionic; if the charge is positive, it is called cationic. If a surfactant contains a head with two oppositely charged groups, it is termed zwitterionic.

Some commonly encountered surfactants of each type include:

  • Ionic
    • Anionic (based on sulfate, sulfonate or carboxylate anions)
      • Sodium dodecyl sulfate (SDS), ammonium lauryl sulfate, and other alkyl sulfate salts
      • Sodium laureth sulfate, also known as sodium lauryl ether sulfate (SLES)
      • Alkyl benzene sulfonate
      • Soaps, or fatty acid salts
    • Cationic (based on quaternary ammonium cations)
      • Cetyl trimethylammonium bromide (CTAB) a.k.a. hexadecyl trimethyl ammonium bromide, and other alkyltrimethylammonium salts
      • Cetylpyridinium chloride (CPC)
      • Polyethoxylated tallow amine (POEA)
      • Benzalkonium chloride (BAC)
      • Benzethonium chloride (BZT)
    • Zwitterionic (amphoteric)
      • Dodecyl betaine
      • Dodecyl dimethylamine oxide
      • Cocamidopropyl betaine
      • Coco ampho glycinate
  • Nonionic
    • Alkyl poly(ethylene oxide)
    • Copolymers of poly(ethylene oxide) and poly(propylene oxide) (commercially called Poloxamers or Poloxamines)
    • Alkyl polyglucosides, including:
      • Octyl glucoside
      • Decyl maltoside
    • Fatty alcohols
      • Cetyl alcohol
      • Oleyl alcohol
    • Cocamide MEA, cocamide DEA, cocamide TEA
Retrieved from "http://en.wikipedia.org/wiki/Surfactant"