effects of side-chain bulk on polymer spatial configurations

 Dear Netters,
 I am looking for published examples of cases in which the strong steric
 interactions between the side-chain and main-chain produces a large
 influence on the spatial configuration of polymer molecules.  I
 understand that examples are found among the polyolefins, poly(vinyl ethers),
 poly(alkylene oxides), poly(methyl acrylates), poly(chloral), and
 polysaccharides, but I am looking for cited references in the literature.
 I appreciate any suggestions.
 Bill Welsh
 Dept of Chem.
 Univ. of Missouri-St. Louis