Nanoporous materials via polymerization-induced microphase separation

Abstract

A porous material, characterized by having empty spaces inside the material, has a large surface area and allows size-selective transportation based on the pore size. Specifically, materials with nanometer-scale pores, referred to as nanoporous materials, have extremely large surface areas. Hence, many are used for their absorbency and as a matrix for catalysts. Moreover, nanometer-scale materials can be size-selectively transported through well-defined nanopores.

Block polymers are structures of two or more polymers connected by a covalent bond. Due to the attraction tendency of identical polymers, block polymers have a self-assembly structure known as a microphase-separation structure. Microphase-separation structures are uniform and controlled structures on the nanometer scale. Using a microphase-separated block polymer as a precursor, nanoporous polymers can be simply obtained through the selective removal of one component. In particular, nanoporous polymers with a continuous porous structure can be obtained simply through polymerization-induced microphase-separation (PIMS) methods. When using PIMS methods, polymerization of the second monomer at the end of the sacrificial polymer serves to derive the microphase-separation structure and a fixed continuous structure. The resulting nanoporous polymers have a continuous structure with a controlled pore size.

This thesis explains the results of a study of nanoporous materials derived from PIMS. First, chapter 1 briefly explains the microphase-separation behavior of block polymers and the generation of nanoporous polymers using a block polymer precursor. This chapter also describes the generation of a continuous nanoporous polymer via the polymerization-induced microphase-separation (PIMS) method. Chapter 2 describes the preparation and tuning of the mechanical properties of nanoporous films via photoinitiated PIMS methods. Chapter 3 presents the results of a study on the synthesis of microcapsules with nanoporous polymers via a microfluidics technique and the PIMS method. Finally, in chapter 4, the preparation of nanoporous SiCN via the PIMS method using a SiCN precursor as a matrix monomer is described.