Substantially symmetrical 3-arm star block copolymers

1. A composition of matter comprising a 3-arm star block copolymer having a central core and diblock copolymer arms having inner blocks and outer blocks, wherein:

(a) the central core is derived from a structure having the formula R 1 C[(AO)(C(O)(CH 2 ) 2 C(CH 3 )(CN))SC(S)Z] 3 , wherein R 1 is selected from the group consisting of H, CH 3 , and C 2 H 5 ; A is selected from the group consisting of CH 2 , and 4-substituted C 6 H 4 ; and Z is SR 2 , wherein R 2 is selected from the group consisting of C 1 -C 4 alkyl, C 12 H 25 and C 6 H 5 ;

(b) the inner blocks are derived from the polymerization of Monomer 1,

wherein X is H or methyl, R is selected from the group consisting of C 1 -C 8 alkyl and partially fluorinated alkyl groups, optionally substituted with hydroxyl or protected hydroxyl groups; and C 3 -C 8 cycloalkyl groups; and

(c) the outer blocks are covalently attached to the inner blocks, wherein the outer blocks are derived from the polymerization of Monomer 2,

wherein Ar is selected from the group consisting of a pyridyl group, a phenyl group, or a phenyl group having substituents selected from the group consisting of alkyl, hydroxyl, acetoxy, C 1 -C 4 alkoxy groups, and

—OC(O)OR′, where R′ is selected from the group consisting of C 1 -C 8 alkyl groups.

2. The composition as set forth in claim 1 , wherein Monomers 1 and 2 are selected such that the difference between the total surface energy values of a homopolymer of Monomer 1 and a homopolymer of Monomer 2 is greater than 10 dynes/cm.

3. The composition as set forth in claim 1 , wherein the inner blocks comprise 5-95 wt % of the diblock copolymer arms.

4. The composition as set forth in claim 1 , wherein the weight average molecular weight of the substantially symmetrical 3-arm star block copolymer is between 5,000 and 250,000.

5. The composition as set forth in claim 1 , wherein R is selected from the group consisting of methyl, cyclohexyl, and a partially fluorinated alkyl group.

6. The composition a set forth in claim 5 , wherein the partially fluorinated alkyl group is selected from the group consisting of —CH 2 C(CF 3 ) 2 OH, —CH 2 CH 2 CH 2 CF 2 C 4 F 9 , —CH 2 CH 2 C 6 F 13 , and -octafluoropentyl.

7. The composition as set forth in claim 1 , wherein Ar is selected from the group consisting of pyridyl, phenyl, acetoxyphenyl, methoxyphenyl, and phenyl substituted with OC(O)OR′, where R′ is t-Bu.

8. The composition as set forth in claim 1 , wherein the inner block is derived from the polymerization of a monomer selected from the group consisting of isobornyl methacrylate, trifluoroethyl methacrylate, trifluoropropyl methacrylate, hexafluoroisopropyl methacrylate, octafluoropentyl methacrylate, CH 2 ═C(CH 3 )CO 2 CH 2 C(CF 3 ) 2 OH and its protected analogues, CH 2 ═C(CH 3 )CO 2 CH 2 CH 2 CH 2 CF 2 C 4 F 9 , CH 2 ═C(CH 3 )CO 2 CH 2 CH 2 C 6 F 13 , CH 2 ═C(CH 3 )CO 2 CH 2 CH 2 C 4 F 9 , CH 2 ═C(CH 3 )CO 2 CH 2 CH 2 C 3 F 7 , CH 2 ═C(CH 3 )CO 2 CH 2 C 2 F 5 , and CH 2 ═C(CH 3 )CO 2 CH 2 C 3 F 7 .

9. An article comprising a substrate, a block copolymer composition on the substrate, and a neutral layer between the substrate and the block copolymer composition, wherein the block copolymer composition comprises a 3-arm star block copolymer having a central core, an inner block and an outer block, wherein:

(a) the central core is derived from a structure having the formula R 1 C[(AO)(C(O)(CH 2 ) 2 C(CH 3 )(CN))SC(S)Z] 3 , wherein R 1 is selected from the group consisting of H, CH 3 , and C 2 H 5 ; A is selected from the group consisting of CH 2 , and 4-substituted C 6 H 4 ; and Z is SR 2 , wherein R 2 is selected from the group consisting of C 1 -C 4 alkyl, C 12 H 25 , and C 6 H 5 ;

(b) the inner block is derived from the polymerization of Monomer 1,

wherein X is H or methyl, R is selected from the group consisting of C 1 -C 8 alkyl and partially fluorinated alkyl groups, optionally substituted with hydroxyl or protected hydroxyl groups; and C 3 -C 8 cycloalkyl groups; and

(c) the outer block is covalently attached to the inner block, wherein the outer block is derived from the polymerization of Monomer 2,

wherein Ar is selected from the group consisting of a pyridyl group, a phenyl group, or a phenyl group having substituents selected from the group consisting of alkyl, hydroxyl, acetoxy, C 1 -C 4 alkoxy groups, and

—OC(O)OR′, where R′ is selected from the group consisting of C 1 -C 8 alkyl groups.

10. The article as set forth in claim 9 , wherein the substrate is pre-patterned with features selected from the group consisting of curved lines, straight lines, line segments, and dots.

11. A composition of matter having the following formula:

wherein:

(a) R 1 is selected from the group consisting of H, CH 3 , and C 2 H 5 ;

(b) A is selected from the group consisting of CH 2 , and 4-substituted C 6 H 4 ;

(c) monomer 1 is an inner block and is derived from the polymerization of Monomer 1,

wherein X is H or methyl, R is selected from the group consisting of C 1 -C 8 alkyl and partially fluorinated alkyl groups, optionally substituted with hydroxyl or protected hydroxyl groups; and C 3 -C 8 cycloalkyl groups; and

(d) monomer 2 is an outer block covalently attached to the inner block and is derived from the polymerization of Monomer 2,

wherein Ar is selected from the group consisting of a pyridyl group, a phenyl group, or a phenyl group having substituents selected from the group consisting of hydroxyl, acetoxy, C 1 -C 4 alkoxy groups, and

—OC(O)OR′, where R′ is selected from the group consisting of C 1 -C 8 alkyl groups;

(e) n is in the range of from about 10 to about 1,000; and

(f) m is in the range of from about 10 to about 1,000.