CHAPTER 5
 TWO-DIMENSIONAL POLYMERIC NANOMATERIALS THROUGH CROSS-LINKING
 OF POLYBUTADIENE-b-POLY(ETHYLENE OXIDE) MONOLAYERS AT THE
 AIR/WATER INTERFACE

 5.1 Introduction

 The idea of stabilizing amphiphilic self-assemblies by polymerization was introduced at

least thirty years ago for monolayers and about ten years later for bilayer vesicles.161,16 This

approach to bridging the nanoscale world of labile, interfacially driven self-assemblies with the

meso-scale has resulted in several examples of cross-linked 3D structures.163-16 For example,

Bates and co-workers were the first to succeed in retaining the cylindrical morphology formed by

gigantic wormlike rubber micelles of polybutadiene-b-poly(ethylene oxide) (PB-b-PEO) diblock

copolymers in water by chemical cross-linking of the PB cores through their pendant 1,2-double

bonds.163,167,168 However, relatively few groups have shown interest in stabilization by cross-

linking of two-dimensional (2D) polymeric self-assemblies formed at the air/water (A/W)

interface; most studies have involved interfacial polymerization of small molecules in Langmuir

monolayers.16-9

 In the early 1970's, Veyssie and co-workerS180,190,191,193 were the first to demonstrate the

formation of 2D cross-linked materials by cross-linking monolayers of dimethacrylates and

several other difunctional reactive amphiphiles under UV irradiation for a constant surface

pressure at the A/W or the oil/water interface. This idea inspired other research groups and

several examples followed. Regen and co-workers introduced the concept of a 2D-network of

molecular pores, i.e. "perforated monolayers" derived from calix[n]arene-based amphiphiles.183-

Iss Cross-linking with malonic acid or via UV irradiation enabled them to synthesize porous and

cohesive "perforated monolayers" with pore diameters in the range 2-6 A+ potentially applicable

for gas permeation selectivity.186,187,189 Michl and co-workers synthesized grids through the