Capacity for heat absorption by the wings of the butterfly Tirumala limniace (Cramer)

Butterflies can directly absorb heat from the sun via their wings to facilitate autonomous flight. However, how is the heat absorbed by the butterfly from sunlight stored and transmitted in the wing? The answer to this scientific question remains unclear. The butterfly Tirumala limniace (Cramer) is a typical heat absorption insect, and its wing surface color is only composed of light and dark colors. Thus, in this study, we measured a number of wing traits relevant for heat absorption including the thoracic temperature at different light intensities and wing opening angles, the thoracic temperature of butterflies with only one right fore wing or one right hind wing; In addition, the spectral reflectance of the wing surfaces, the thoracic temperature of butterflies with the scales removed or present in light or dark areas, and the real-time changes in heat absorption by the wing surfaces with temperature were also measured. We found that high intensity light (600–60,000 lx) allowed the butterflies to absorb more heat and 60−90° was the optimal angle for heat absorption. The heat absorption capacity was stronger in the fore wings than the hind wings. Dark areas on the wing surfaces were heat absorption areas. The dark areas in the lower region of the fore wing surface and the inside region of the hind wing surface were heat storage areas. Heat was transferred from the heat storage areas to the wing base through the veins near the heat storage areas of the fore and hind wings

Development of biopolymeric patterned thin films

Patterned surfaces are a crucial technology in material science. According to the OECD (Organisation for Economic Co-operation and Development), over 20% of emerging technologies (in renewable energy, biomedical devices, smart devices and anti-reflective surfaces) utilize patterned surfaces. The widespread use of these materials is because nanoand microscale patterns on a surface impart specific physicochemical properties to that surface. Thus, being able to control the nano and micro- surface patterns allows for modification of a material’s surface properties, which in turn allows for tailorable materials for technological needs.However, currently the fabrication methods of almost all the necessary technologies of everyday life are unsustainable, including the current generation of patterned surfaces, which rely on inefficient manufacturing methods (in certain instances), and unsustainable feedstocks (petrochemically derived polymers) that require expensive extraction. We are living through an unprecedented sustainability crisis. Almost every functional system humans rely on – energy, transport, food, technology, communications – is dependent on fundamentally unsustainable materials and practices. To alleviate this, we must produce as much of the critica components of our technologies as sustainably as possible. Patterned surfaces are just such a critical component. To ensure that things like future renewable energy technologies are truly renewable, we must ensure that their fundamental components are sustainable. Patterned surfaces are produced by phase separating synthetic polymer blends or block copolymers (BCPs), Figure 1.1. Little work has been done in producing patterned surfaces using sustainably sourced materials. This thesis describes the production of patterned surfaces using waste biopolymers. Biopolymers, unlike synthetic polymers, are renewable, biocompatible, biodegradable and are some of the most abundant materials on the planet. Utilizing waste biopolymers, agricultural waste can be minimized using a circular economy system, while simultaneously reducing our reliance on petrochemicals. Not only are biopolymers more sustainable but their innate physico-chemical characteristics will permit larger scale pattern features and superior, application-specific functionalities. The aim of this project was to produce patterned thin-films (PTFs), using biopolymer blends. To produce these biopolymer blend thin films, a technique called segregative phase separation was used to promote pattern development using a protein and polysaccharide biopolymer, in an acidic solvent. These patterned films have similar size profiles and chemistries to synthetic polymer blends, and demonstrate that we need not rely on petrochemically derived polymers when producing patterned surfaces