Photochemistry is a powerful tool that can be used to selectively modify surface properties on soft (e.g. polystyrene) and hard (e.g. silicon wafer) substrates. Using light to impart functionality allows for the creation of a surface with high spatial resolution.

In 2005, we photochemically patterned polymer substrates by functionalizing the surface with photoactive diblock copolymers. In the presence of a photoacid generator and subsequent exposure to UV light, tert-butyl acrylamide groups (Fig. 1a, solid red) were ‘deprotected’ to form acrylic acid groups (Fig. 1a, dotted red) in the irradiated regions.

In 2006, we photopatterned phthalimide self-assembled monolayers (SAMs) by grafting polysaccharides onto silicon wafers (Fig. 2). In 2007, we photogenerated glycan arrays onto mixed phthalimide-amine SAMs: irradiation of the mixed SAMs in the presence of polysaccharides (Fig. 3a, red) produced glycan arrays that were subsequently used to detect B. anthracis spores (Fig. 3b).

See also a review in E. J. Park, G. T. Carroll, N. J. Turro and J. T. Koberstein, Soft Matter, 2009, 5, 36-50.

Polymer Photomodification of Soft and Hard Substrates Nicholas J. Turro and Jeffrey T. Koberstein, Columbia University

G. T. Carroll, et. al. Langmuir 2006, 22, 2899; D. Wang, et al. Proteomics 2007, 7, 180.

Soft Substrate

Hard Substrate

Figure 3. (a) Schematic of mixed SAM/polysaccharide irradiation. (b) Glycan array used to detect B. anthracis spore.

Figure 1. (a) Schematic of ptBA/PAG irradiation. (b) Optical micrograph of a patterned PS substrate with ptBA and pAA regions indicating thickness changes perhaps due to loss of tert-butyl groups.

F. Pan, P. Wang, K. Lee, A. Wu, N. J. Turro and J. T. Koberstein, Langmuir, 2005, 21, 3605.

Photomask

DUV

PS substrate

PAG

PtBA

PS

1) h

2)

PAA

PS substrate

100 m

a) b)

O CH2O

OCH2

OOH2CO

O

O

H2C

O

O

H2C O

OH2C O

OCH2

O

NH2

Si

OO

NH2

Si

OO

NH2

Si

OO

NH2

Si

OO

N

Si

OH

O

OOO

NH2

Si

OO

O CH2O

OCH2

OOH2CO

O

O

NH2

Si

OO

NH2

Si

OO

NH2

Si

OO

NH2

Si

OO

N

Si

O

O

OOO

NH2

Si

OO

H2C

O

O

H2C O

OH2C O

OCH2

O

h Antibodies

a) b)

Figure 2. Optical micrograph of water selectively condensed on regions of grafted polysaccharides (dark).

CHE 0717518CHE 0415516DMR-0704054

Education and Outreach Objectives: REU, RET, High School, International CollaborationNicholas J. Turro and Jeffrey T. Koberstein, Columbia University

Collaborations• Columbia Dept. of Chemistry • Columbia Dept. of Chem. Eng.• Stanford University Med. School • Univ. Texas at Austin• Cornell University • Sematech• United States Military Academy • Scripps Research Institute• Kyoto University • Brown University• University of Urbino • and many others!

EducationSince 2004, these grants have supported the following students at Columbia University: 12 graduate students pursuing their Ph.D degrees, 10 students who have completed their Ph.D. dissertations, 11 post-doctoral associates, 9 undergraduate students and one high school student.

Outreach• Hosted high school student from Masters School (NY)• Hosted several undergraduates through REU programs• Hosted RET during summer 2008 from Singapore • Student member coordinated Girls’ Science Day 2008• NSF GK-12 LEEFS fellow coordinates lessons with grade schools in Brooklyn and Dominican Republic. • Two graduate students have presented posters at IGERT conference hosted by University of Oregon in December 2008.• 124 peer-reviewed papers have been published to communicate our work to a broad audience.

LEFT: Alison Schultz (REU 2008, University of Rhode Island, Rhode Island) and RIGHT: Choon Huat (Bryan) Lim (RET 2008, Innova Junior College, Singapore)

Alex Paris (High School 2008, Masters School, New York)

Attendees of IGERT Conference, Gleneden Beach, Oregon, December 2008

CHE 0717518CHE 0415516DMR-0704054