Nanoporous polymers with functionalized one-dimensional and three-dimensional channels from ordered block copolymer templates

Nanoporous polymeric materials from ordered block copolymer templates are typically prepared by selective removal of the minority component from one of the traditional non-lamellar diblock copolymer phases, namely spherical, gyroid, and cylindrical morphologies. These resulting nanoporous polymeric materials with predictable and reproducible pore sizes, microstructure alignment, and with ready access to adjustable pore wall functionality, offer many advantages relative to their inorganic counterparts for nanotechnological applications.; This thesis focuses on the preparation of advanced nanoporous polymeric materials with adjustable pore wall functionality, containing one-dimensional and three-dimensional nanochannels. In addition new chemical etching methods were developed. Firstly, an established HI chemical etching method was used to degrade poly(ethylene oxide) (PEO) selectively and efficiently from an asymmetric polystyrene-poly(ethylene oxide) (PS-PEO) diblock copolymer. This methodology represents a simple and straightforward protocol for the generation of ordered nanoporous materials from widely available PEO containing block copolymers. This method has also been applied to an asymmetric PS-polylactide (PLA) diblock copolymer. Secondly, a systematic study on the morphological behavior and the miscibility limit of the binary blends of PS-PLA and PS-PEO was explored. Hydrophilic nanoporous PS materials with PEO-coated pore walls were successfully prepared by selective removal of PLA from such blends. Thirdly, bulk nanoporous PS with three-dimensional nanochannels, which are particularly preferred over wellestablished cylindrical channels for filtration applications, were prepared from PS-PLA and PSPEO diblock copolymers and binary blends of PS-PLA and PS-PEO, all adopting the gyroid morphology at RT via thermal annealing and subsequent quenching. Lastly, the HI etching methodology was extended to two PS-polyisoprene (PI)-PEO triblock samples with a core-shell cylindrical morphology and a network morphology and one PI-PS-PEO triblock sample with a three-domain lamellae morphology to make nanoporous polymeric materials. Simultaneously, the double bonds in the PI blocks were modified through the HI addition or by the HI-initiated self-crosslinking.; Appendix 1 presents our efforts to make elastomeric nanoporous polymeric materials through selectively crosslinking the matrix block in polybutadiene (PB)-PLA, PLA-PI-PLA and (PS-ran-PI)-PLA polymeric systems via thermal peroxide and S2Cl2 crosslinking reactions. The extension of HI etching method to PS-PEO thin films is described in Appendix 2.