Show simple item record

dc.contributor.advisorChen, Wei
dc.contributor.authorLaudadio, Elizabeth
dc.date.accessioned2015-05-11T21:42:51Z
dc.date.available2015-05-11T21:42:51Z
dc.date.issued2015-05-11
dc.identifier.urihttp://hdl.handle.net/10166/3634
dc.description.abstractWhile gold nanoparticles (AuNPs) have many potential applications, a common obstacle to their use is their propensity to aggregate together. We propose a solution to this issue through conjugation with poly(vinyl alcohol) (PVOH), a biocompatible and water-soluble polymer. PVOH stabilizes AuNPs in solution, and also can act as a spacer for 2D self-assemblies of AuNPs. The binding mechanisms of PVOH onto AuNPs were studied using dynamic light scattering and through the construction of Langmuir adsorption isotherms. Self-assembled 2D arrays of AuNPs have important applications in numerous areas of science and technology including printing, catalysis, molecular sensing, and microassay manufacturing. A simple and effective way to form this type of array would be to deposit sessile drops containing AuNPs onto desired substrates. However, colloids in solution typically form non-uniform deposit patterns upon solvent evaporation, commonly known as “coffee rings.” Deposit patterns on substrates of varying wettabilities were studied using optical microscopy and atomic force microscopy to gain insight into the mechanisms of droplet drying. It was found that the deposit pattern on superhydrophilic substrates is a highly regular, monodisperse layer of AuNPs. It was also found that on hydrophobic surfaces, the contact area of the droplet, ring thickness, and ring width were all functions of the receding contact angle of the substrate. Through these studies, it was discovered that relative humidity plays an important role in deposit pattern formation. Under high humidity, drying occurs more slowly, and deposits form more regularly. In the future, these studies will be performed in controlled humidity environments.en_US
dc.description.sponsorshipChemistryen_US
dc.language.isoen_USen_US
dc.subjectchemistryen_US
dc.subjectgold nanoparticlesen_US
dc.subjectpoly(vinyl alcohol)en_US
dc.subjecttris(trimethylsiloxy)chlorosilaneen_US
dc.subjectsurface chemistryen_US
dc.subjectnanoscienceen_US
dc.subjectmaterials chemistryen_US
dc.subjectcoffee ringen_US
dc.subjectdeposit patternen_US
dc.subjectdrying dynamicsen_US
dc.subjectlangmuir adsorption isothermen_US
dc.subjectself-assemblyen_US
dc.subjectself assembled monolayersen_US
dc.subjectwettabilityen_US
dc.subjecthydrophobicen_US
dc.subjecthydrophillicen_US
dc.titleUNDERSTANDING “COFFEE-RINGS” ON MOLECULARLY SMOOTH AND CHEMICALLY MODIFIED SUBSTRATES USING AQUEOUS SOLUTIONS OF GOLD NANOPARTICLES STABILIZED BY POLY(VINYL ALCOHOL)en_US
dc.typeThesis
dc.date.gradyear2015en_US
mhc.institutionMount Holyoke College
mhc.degreeUndergraduateen_US
dc.rights.restrictedrestricteden_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record