The innovation engine for new materials

Elke Peirtsegaele

University: 

University of California, Santa Barbara

Major: 

Chemical Egineering

Site Abroad: 

Technical University Eindhoven

Mentor(s): 

Miguel Garcia

Faculty Sponsor(s): 

E.W. Bert Meijer

Faculty Sponsor's Department: 

Chemical Engineering

Project Title: 

THE STUDY OF THE SELF-ASSEMBLY OF SUBSTITUTED BTAS

Project Description: 

Self-assembly has increasingly fascinated supramolecular (organic) chemists throughout the world due to its ability to form complex structures from simple molecules.  Symmetric and asymmetric benzene-1,3,5-tricarboxamides (BTAs) consisting of oligodimethylsiloxane (specifically polydimethylsiloxane) and alkyl chains were synthesized and characterized for the study of the self-assembly of substituted BTAs.  The influence of the position of these substitutes on the BTA’s liquid crystalline formation and aggregation behavior in solution was investigated using a variety of techniques including Infrared (IR) and UV-Vis Spectroscopy, Polarized Optical Microscopy (POM), Differential Scanning Calorimetry (DSC), and Atomic Force Microscopy (AFM).  IR spectroscopy and the formation of organogels confirmed that BTA molecules formed aggregates by means of hydrogen bonding.  Temperature dependent UV-Vis demonstrated that the BTA molecules formed aggregates at different concentrations in methylcyclohexane (MCH), an apolar solvent that stabilizes the hydrogen bonding between BTA molecules.  POM measurements confirmed that the flat-shaped discotic BTA molecules stacked one-dimensionally to form columnar liquid crystals due to the hydrogen bonded stacking between BTA cores.  Upon the formation of these liquid crystals, additional DSC measurements were performed in order to study the transition between the anisotropic and isotropic phases of each BTA’s liquid crystals.  The final goal of the project was to use the polydimethylsiloxane (PDMS) and alkyl substituted BTAs to make thin films by converting the block-copolymers onto a silica surface via oxygen plasma treatment to produce topographically patterned silica.