Integrating block copolymer self-assembly with existing lithography processes to enhance their patterning capability is a promising approach for manufacturing a variety of semiconductor devices and next-generation magnetic storage media. Sub-10 nm block copolymer domains are specifically targeted in many of these applications, yet there are relatively few block copolymers that can achieve these dimensions: Here the synthesis and self-assembly characteristics of a new block copolymer poly(trimethylsilylstyrene-b-D,L-lactide) (PTMSS-b-PLA) capable of forming domains as small as similar to 5 rim are described. Several lamellar and cylinder forming diblocks were synthesized with bulk domain periodicities of 12-15 nm which are among the smallest domains yet reported for any neat block copolymer. Such small domains are possible because this new material has a large segment segment interaction parameter which is an order of magnitude higher than poly(styrene-b-methyl methacrylate) (PS-b-PMMA) and twice as large as poly(styrene-b-dimethylsiloxane) (PS-b-PDMS), two commonly studied polymers for these applications. Furthermore, the PTMSS-b-PLA blocks have glass transitions Well above room temperature with a large reactive Ion etch rite contrast between them (similar to 28) which is at least 4 times greater than PS-b-PMMA due to incorporation of a trimethylsilyl group into the styrene Monomer.