The viscosity of a surfactant mixture is dependant upon the size of the micelles in the system. This is determined by several factors - concentration of surfactants, the type and ratio of species, temperature and charge density on the micelles.
In mixed micelles the arrangement of the molecules is limited to some extent by the charge density on the surface of the micelle. This can be reduced in several ways.

Вязкость смеси ПАВ зависит от размера мицеллы в системе. Это обуславливается несколькими факторами – концентрацией ПАВ, the type and ratio of species, температуры и плотности заряда на мицелле. В смешанных мицеллах расположение молекул в некоторой степени ограничено плотностью заряда на поверхности мицеллы. Это можно понизить несколькими способами.

заранее спасибо!

Ну вообще такое слово там звучало.

Question 2
What is the actual interaction between the salt and all other ingredients in the shampoo on the molecular scale?

Answer

The viscocity of a surfactant mixture is dependant upon the size of the micelles in the system. This is determined by several factors - concentration of surfactants, the type and ratio of species, temperature and charge density on the micelles.
In mixed micelles the arrangement of the molecules is limited to some extent by the charge density on the surface of the micelle. This can be reduced in several ways.

Addition of more nonionic surfactant so that the ratio in the micelles rises and the negatively charged heads of the anionic surfactants are held further apart.

Additon of a substance that reduces the charge density on the surface of the micelles.ie salt. The sodium ions of the salt affect the dissociation constant of the anionic surfactant in the formulation and the balance is forced back to the left of the dissociation equilibrium equation. C12SO4Na = C12SO4- + Na+ (sorry my e mail won't allow me to add proper characters for this equation)
Это не для перевода :) просто контекст 8-)

Так что получается следующее:
The viscosity of a surfactant mixture is dependant upon the size of the micelles in the system. This is determined by several factors - concentration of surfactants, the type and ratio of species, temperature and charge density on the micelles.
Вязкость смеси, содержащей ПАВ, зависит от размера мицелл в системе. Этот размер определяется несколькими факторами – концентрацией ПАВ, видом молекул и их соотношением, температурой и плотностью заряда мицеллы.