Journal article
Synthesis, preparation, and conformation of stimulus-responsive end-grafted poly(methacrylic acid-g-ethylene glycol) layers
Soft matter, v 2(3), pp 243-256
07 Mar 2006
PMID: 32646151
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Here we report the formation of stimulus-responsive chemically end-grafted 'brush-brushes' by synthesizing, mono thiol(end)-functionalized poly(methacrylic acid-g-ethylene glycol) or poly(MAA-g-EG) comb-type graft copolymers via a combination of protecting group chemistry and atom transfer radical polymerization using the initiator 2-(2,4-dinitrophenylthio)ethyl 2-bromo-2-methyl propionate. The polymers were synthesized with three different molecular weights (15 k, 17 k and 27 k), PEG side chain graft densities (EG/MAA mole ratio = 2.,0.4 and 1.9, respectively), and a PEG molecular weight = 1100 and then chemically end-grafted to gold substrates via chemisorption, resulting in molecular separation distances of -3-4 nm. pH-Dependent swelling was confirmed to take place gradually above pH 4-5 and quantified by heights measured by contact mode AFM imaging of microcontact printed (.tCP) samples. Swelling factors (maximum height/minimum height) were fairly large (3.6-7.3) and a decrease in molecular weight by 2 x and side chain graft density by 4 x resulted in a decrease in swelling factor by -2 x . Layer height versus normal force for all three polymers measured by contact mode atomic force microscope imaging on p,CP samples at pH 9 showed a nonlinearly decreasing relationship and complete compression - < 2 nm for forces > 10 nN. At pH 4, all polymer layers were largely collapsed (heights - < 4 nm) and incompressible (i.e., heights were independent of normal force).
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Details
- Title
- Synthesis, preparation, and conformation of stimulus-responsive end-grafted poly(methacrylic acid-g-ethylene glycol) layers
- Creators
- Miao Ye - Massachusetts Institute of TechnologyDong Zhang - Massachusetts Institute of TechnologyLin HanJonathon Tejada - Massachusetts Institute of TechnologyChristine Ortiz - Massachusetts Institute of Technology
- Publication Details
- Soft matter, v 2(3), pp 243-256
- Publisher
- Royal Society of Chemistry
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- School of Biomedical Engineering, Science, and Health Systems
- Web of Science ID
- WOS:000235972700009
- Scopus ID
- 2-s2.0-33344472484
- Other Identifier
- 991019186956804721
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InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Chemistry, Physical
- Materials Science, Multidisciplinary
- Physics, Multidisciplinary
- Polymer Science