GRADUATE STUDENT SEMINARS - Kristine Liao, ,Juzheng Frank Huang, Chenguang Sun & Mark Eddleston

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• University of Cambridge
• Tuesday 15 June 2010, 16:00-18:00
• Pfizer Lecture Theatre, Department of Chemistry.

If you have a question about this talk, please contact Tina Jost.

This talk has been canceled/deleted

Kristine Liao:

“Single Crystal Adsorption Calorimetry and the Fischer-Tropsch Synthesis”

The Fischer-Tropsch (F-T) reaction synthesizes aliphatic hydrocarbons from carbon monoxide and hydrogen catalyzed by iron or cobalt. One important factor in these gas-solid interactions is the total energy of the ground state of the adsorbate. Single crystal adsorption calorimetry is one technique that can be used to directly measure this parameter. The aim is to measure the coverage-dependent differential heat of adsoprtion for the coadsorption of carbon monoxide and hydrogen on iron and cobalt surfaces. This would provide information regarding the energetics of the catalytic process. In this talk, the principle of the single-crystal calorimetric technique will be discussed, together with an outline of recent upgrades to the equipment. The relevance of this work to the catalytic reaction will be highlighted.

Juzheng Frank Huang:

“Electronic nose composed of individual clicked receptor-coated microcantilever sensors”

Microcantilever sensors, which can transform bio/chemical reactions into recordable mechanical signals, provide a platform to detect the analyte molecules with the fast response and ultrasensitivity. We have prepared a library of microcantilver chips coated with receptor polymer brushes as well as self assembled monolayers presenting a variety of headgroups by using click chemistry. The affinity of these surface coatings towards different solvents has been investigated using MC sensors interrogated by phase-shifting interferometric microscopy (PSIM) in both vapor and liquid phase. The microcantilever array sensor has been convinced to discriminate between a nerve-gas simulant and other solvent vapors.

Chenguang Sun:

“The adsorption of iodo alkanes and the mixture of acid/amine on the graphite”

Hydrocarbons play a very important role in numerous commercial applications that exploit their novel behaviour at interfaces, particularly as friction modifiers in polymers, anti-wear agents in lubrication formulations and antistats. A very important recent challenge is the construction of higher level surface superstructures using a number of non-bonded interactions between the adsorbed species such as hydrogen bonds. We and others have found that the hydrogen bonds are able to form both molecular dimers but also extended chains of the adsorbed molecules. In this work we propose to extend the study to another important non-bonded interaction, that between iodine atoms and the hydrogen bonding between –NH2 and –COOH groups.

Mark Eddleston:

“Transmission Electron Microscopy of Pharmaceutical Materials”

Characterising and understanding the solid form of pharmaceutical compounds is vital as different crystal phases have different properties, including bioavailability. Though transmission electron microscopy has long been a key analytical technique in materials science, its use for characterisation of pharmaceutical samples has been very limited. This is largely due to difficulties associated with the preparation of appropriately thin samples, as well as issues with sample damage caused by the electron beam. In this talk, straightforward approaches for overcoming these difficulties will be described which have enabled analysis of a variety of pharmaceutical compounds, including theophylline, paracetamol and aspirin. A range of relevant information about these compounds has been obtained including morphology, polymorph identification and crystal defect characterisation.

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