Control of crystallization in supramolecular soft materials engineering

As one class of the most important supramolecular functional materials, gels formed by low molecular weight gelators (LMWGs) have many important applications. The key important parameters affecting the in-use performance of a gel are determined by the hierarchical fiber network structures. Fiber networks consisting of weakly interacting multiple domains are commonly observed in gels formed by LMWGs. The rheological properties, particularly the elasticity, of a gel with such a fiber network are weak due to the weak interactions between the individual domains. As achieving desirable rheological properties of such a gel is practically relevant, in this work, we demonstrate the engineering of gels with such a type of fiber network by controlling crystallization of the gelator. Two example gels formed by a glutamic acid derivative in a non-ionic surfactant Tween 80 and in propylene glycol were engineered by controlling the thermodynamic driving force for crystallization. For a fixed gelator concentration, the thermodynamic driving force was manipulated by controlling the temperature for fiber crystallization. It was observed that there exists an optimal temperature at which a gel with maximal elasticity can be fabricated. This will hopefully provide guidelines for producing high performance soft materials by engineering their fiber network structures.

Architecture of fiber network : from understanding to engineering of molecular gels

A new approach of engineering of molecular gels was established on the basis of a nucleation-initiated network formation mechanism. A variety of gel network structures can be obtained by regulating the starting temperature of the sol−gel transition. This enables us to tune the network from the spherulitic domains pattern to the extensively interconnected fibrillar network. As the consequence of fibrous network structure turning, desirable rheological and other in-use properties of the materials can be obtained accordingly. This approach of micro-/nanostructural fabrication may open up a new route for micro-/nanofunctional materials engineering in general.

Use of web-conferencing software to enhance practical learning for distance students in a first-year Engineering course

BACKGROUND : For many years, Deakin University has delivered an accredited undergraduate engineering course by means of distance education. One of the chief challenges is to provide the necessary practical instruction and experience in engineering to these students. In first-year physics and first-year materials science, off-campus students normally attend on-campus lab classes either on a Saturday or as part of a residential school. However, because some students live either interstate or overseas, it is sometimes impossible for small groups of students to attend an on-campus lab class. PURPOSE : This paper investigates whether web-conferencing software can be an effective means for delivering practical classes to small groups of distance students in first-year physics and also first-year materials. METHOD : Over three semesters in 2012, we employed the Elluminate-Live! software platform to broadcast six lab practicals in first-year physics, and one practical in first-year materials engineering. The students submitted practical reports as did all the other students in each unit. The students in each unit fell into three groups: on-campus students, off-campus students who performed their practicals on-campus, and off-campus students who performed their practicals “virtually” via an Elluminate-Live! session. RESULTS : The trials showed that it is possible to broadcast both physics and materials practical classes by means of web-conferencing software. Report marks of the students performing practicals by this method were comparable to those in the other groups. CONCLUSIONS : Our experience with four initial trials in delivering practical classes over the Internet was encouraging, and showed that the concept will work if done in an effective way.

Student opportunities in materials design and manufacture: Introducing a new manufacturing with composites course

The shift towards strong and lightweight fibre reinforced polymer-matrix composites for many high performance applications has resulted in an increasing need to expose students to composite design and manufacture courses in the undergraduate curriculum. In contrast, student exposure to composite materials is often still limited to a topic within a materials or manufacturing related course (unit). This paper presents the initial offering of a composite materials elective at Griffith University in Australia. The course also addresses environmental concerns through the inclusion of natural fibre composites. An evaluation of student perceptions is considered from Griffith’s Student Experience of Course (SEC) and separate Student Experience of Teaching (SET) surveys. These evaluations demonstrate the high level of student engagement with the course, but also highlighted areas for improvement, including the need to incorporate even more hands-on practical work. Interestingly, the inclusion of natural fibre composites and the related discussion surrounding environmental and societal issues are not focused on in student feedback.