Chemistry directed assembly of multilayered polymer thin films and colloidal particles

In this thesis, multilayered polymer thin films have been directed to different regions of a surface based on both electrostatic and secondary interactions between the polymer and the surface. This concept of adsorption directed by surface chemistry is universal, in that the same sets of rules derived for polymeric systems can also be applied to molecule and meso-scale systems, including dye molecules, colloidal particles, proteins and cells. An approach of "surface sorting" was proposed to direct two or more objects with varying functionalities to deposit on predetermined regions of a surface based on specific surface interactions. Specifically, on the surface patterned with alternating charged carboxylic acid (COOH) surface groups and neutral oligoethylene glycol (EG) surface groups, linear polyethyleneimine (LPEI) based multilayers predominately adsorb on the COOH surface, with maximal selectivity at the moderate pH level of 4.8; in contrast, polyallylamine hydrochloride (PAH) based multilayers are attracted to the EG surface under certain pH conditions, with maximal selectivity on EG also at a pH of 4.8. Chemical force microscopy was used to directly examine the intermolecular interactions between polyamines and functional surfaces. The driving forces were identified to be primarily an electrostatic interaction for LPEI adsorption on the COOH surface, and primarily a hydrophobic interaction for PAH adsorption on the EG surface, respectively. By combining the results of force measurements and systematic adsorption studies, a set of rules were established that define the conditions required for selective deposition on specific surface regions for polyelectrolyte adsorption.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Chemical Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Jiang, Xueping, 1971-

Advisor dc:contributor.advisor

• Paula T. Hammond.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8534

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8534