Introduction: Block copolymers have a long history as industrial surfactants. The major types of block copolymers, such as those made from ethylene oxide (EO) and propylene oxide (PO) or EO and styrene, are cheap and easy to tailor-make for specific applications. The water-soluble EO-PO block copolymers are stable over a wide pH range and compatible with all other types of surfactants. In addition, they are mild to the skin and hair, a property related to their high molecular weight. In the manufacture of an amphiphilic block copolymer for a specific application there are several degrees of freedom as compared with the synthesis of conventional, low-molecular weight surfactants: (1) the size of both the hydrophilic and the hydrophobic part can be varied at will, (2) the molecular weight can be varied within wide ranges while maintaining constant hydrophilic-lipophilic balance, and (3) the properties and function of a block copolymer at an interface, e.g. oil-water, can be governed by the molecular architecture. As an example, an EO-PO-EO triblock polymer is preferred as steric stabilizer of oil-in-water emulsions whereas water-in-oil emulsions may be better served with a copolymer of PO-EO-PO type. In more recent times slow degradability in the environment of the major type of water-soluble block copolymers, the EO-PO based compounds, has become a major obstacle for both household and industrial use of the products. Improved biodegradability is probably the strongest driving force for the development of new surfactants today and products which do not meet the OECD guideline in rate of degradation into carbon dioxide and water are challenged by alternative products, even if these are more expensive or not as good in terms of technical performance. Environmental considerations have already limited the use of EO-PO block copolymers and are likely to do so even more in the future. Even so, water-soluble block copolymers are still an important surfactant class. The various types of EO-PO based products, often referred to as Pluronics or Polaxamers, which are commercial trade names, constitute the vast majority but ethylene oxide-butylene oxide (EO-BO) copolymers are also on the market. The three smallest alkylene oxide monomers, EO, PO and BO, all give a linear polymer backbone consisting of a repeating C-C-O- segment (see Figure 1).