In this unit, the links between chemical structure, properties and use/application will be made. It can also be used to address the representation of materials at macro, sub-micro and symbolic levels.
The unit is built around the theme of ‘holes’ and that not all holes are visible to the naked eye. Various materials will be tested to determine if they can be effectively used as filters (therefore have holes) and also if different filters have different sized holes. Polymer films are interesting materials here as their structure can be altered by the addition of plastisisers and therefore the size, shape and extent of the holes can be varied. In addition, polymers can be synthesised as required. This can develop for applications such as dialysis, separations, osmosis etc. Also, the use of polymers films with controllable holes in particularly useful applications such as in drug release (as in hydrogels) and in environmental protection (as antimicrobial coatings).
The unit is divided into 3 subunits which can be used independently at different levels. Each subunit can take different directions and emphasis depending on the curriculum and particular learning aims of the teacher. The subunits can also be used in a spiral type curriculum with subunit 1 focussed at an introductory chemistry level, subunit 2 at intermediate level and subunit 3 at the higher stages of second-level school. The activities are designed in such a way that they could be used in different areas of chemistry and biology – e.g. in dialysis or food contamination.micor