CHAPTER 2
 EXPERIMENTAL TECHNIQUES

 In this chapter, an overview of the principal experimental techniques is presented. The

specific detailed experimental procedures are not described here but are included instead at the

end of each of the following chapters in the Experimental sections.

 2.1 Langmuir Monolayers and Surface Pressure Related Experiments

 As further detailed in Chapters 3, 4, and 5, investigation of block copolymer self-assembly

at the air/water (A/W) interface in Langmuir monolayers requires the use of a Langmuir trough.

A typical set-up is shown in Figure 2-1. It provides a very simple method to control monolayer

surface density thanks to the movable barriers controlled by a DC motor. The trough is

composed of an inert material such as for instance Teflon polytetrafluoroethylenee, PTFE) that is

resistant to water absorption.

 Balance Amphiphilic

 r Block copolymers
 S_-Wilhelmy plate


 Teflonm trough IMilli-Q Water


Figure 2-1. The Langmuir Teflon trough.

 To form a Langmuir monolayer, the block copolymer of interest is first dissolved in a

solvent (C 1mg/mL) which is then spread dropwise on the water surface. The solvent must be

hydrophobic to prevent its dissolution in the water subphase and so it doesn't influence the

surface pressure measurements. It should be also volatile enough to quickly evaporate from the

surface after spreading, leaving behind the adsorbed block copolymer molecules. Chloroform

was the solvent of choice in this dissertation except in Chapter 2 where the use of a more polar