Poças de maré são depressões ou cavidades do substrato do entre-marés, formadas tanto em costões rochosos quanto em planícies de maré durante maré baixa. Estudos comparando a ictiofauna de poças arenosas de planícies de maré e de poças rochosas são inexistentes, sendo o presente estudo o primeiro a ser desenvolvido neste âmbito, a fim de colocar em pauta a relevância de poças arenosas para a ecologia e conservação de áreas costeiras. Nossos objetivos neste estudo foram (I) realizar o levantamento das espécies de peixes presentes em poças de maré arenosas e rochosas em uma enseada subtropical, a Baía do Araçá (São Paulo/Brasil); (II) comparar a composição e abundância da ictiofauna entre poças arenosas e rochosas; e (III) identificar quais e como os fatores ambientais estão relacionados à composição e abundância da ictiofauna dessas poças. A estrutura da ictiofauna (composição e abundância de espécies) e fatores ambientais (área, profundidade, salinidade, temperatura, oxigênio dissolvido, porcentagem de cobertura algal e distância das poças até o canal) foram analisados a partir de quatro campanhas realizadas durante 2014. Nas poças arenosas, a ictiofauna foi amostrada utilizando redes de mão, solução de eugenol e picaré seguindo um protocolo de amostragem especialmente desenvolvido para essa categoria de poça; nas poças rochosas, utilizamos eugenol e redes de mão. Verificamos que as poças arenosas foram maiores, mais rasas e mais distantes do canal, sendo estes os fatores ambientais que mais distinguem os dois tipos de poça. A composição e abundância de espécies diferiram entre os tipos de poça e ao longo do ano, sendo em arenosas Gerreidae e Gobiidae as principais famílias e em rochosas Gobiidae e Blenniidae. Os fatores ambientais que estruturaram a ictiofauna em cada tipo de poça foram: nas arenosas, a área, profundidade, cobertura algal e distância até o canal; e nas rochosas, temperatura, oxigênio dissolvido e distância do canal. Além do enfoque que vem sendo dado à ictiofauna de poças rochosas, enfatizamos a importância de estudar aquela de poças arenosas por sua elevada riqueza e abundância em espécies, incluindo larvas de diversas famílias. / Tide pools are depressions or cavities of the intertidal substrate formed in both rocky shores and tidal flats during low tide. Studies on fish populations conducted at sandy pools in tidal flats and their comparison with rock pools do not exist. This study is the first one dealing with such questions, emphasizing the relevance of sandy pools for the ecology and conservation of coastal areas. The objectives of this study were (I) to carry out a survey of fish species in sandy and rocky tide pools in a subtropical bay, the Aracá Bay (São Paulo/Brazil); (II) to compare the composition and abundance of fish fauna between sandy and rocky pools; and (III) to investigate which and how environmental factors are related to the composition and distribution of fish fauna of these pools. The structure of fish populations (composition and abundance of species) and environmental factors (area, depth, salinity, temperature, dissolved oxygen, algal coverage percentage and distance from the pools to the channel) were carried out in four campaigns during 2014. In sandy pools, the fish fauna was sampled using hand nets, eugenol and beach seine, following a sampling protocol specially developed for that purpose; in rocky pools, we used eugenol and hand nets. The sandy pools were larger, shallower and farther from the channel, than the rocky ones. The composition and abundance of fish species differed between the types of pools and throughout the year: Gerreidae and Gobiidae were the main families in the sandy pools and Gobiidae and Blenniidae in the rocky ones. The environmental factors that structured the fish fauna in each type of pool were: in sandy area, depth, algal coverage and distance to the channel; in rocky pools, temperature, dissolved oxygen and channel distance. In contrast to the focus that has been given for rocky pools, we emphasize the importance of sandy pools studies because its great richness and abundance of species, including larvae of many families.

Poças de maré são depressões ou cavidades do substrato do entre-marés, formadas tanto em costões rochosos quanto em planícies de maré durante maré baixa. Estudos comparando a ictiofauna de poças arenosas de planícies de maré e de poças rochosas são inexistentes, sendo o presente estudo o primeiro a ser desenvolvido neste âmbito, a fim de colocar em pauta a relevância de poças arenosas para a ecologia e conservação de áreas costeiras. Nossos objetivos neste estudo foram (I) realizar o levantamento das espécies de peixes presentes em poças de maré arenosas e rochosas em uma enseada subtropical, a Baía do Araçá (São Paulo/Brasil); (II) comparar a composição e abundância da ictiofauna entre poças arenosas e rochosas; e (III) identificar quais e como os fatores ambientais estão relacionados à composição e abundância da ictiofauna dessas poças. A estrutura da ictiofauna (composição e abundância de espécies) e fatores ambientais (área, profundidade, salinidade, temperatura, oxigênio dissolvido, porcentagem de cobertura algal e distância das poças até o canal) foram analisados a partir de quatro campanhas realizadas durante 2014. Nas poças arenosas, a ictiofauna foi amostrada utilizando redes de mão, solução de eugenol e picaré seguindo um protocolo de amostragem especialmente desenvolvido para essa categoria de poça; nas poças rochosas, utilizamos eugenol e redes de mão. Verificamos que as poças arenosas foram maiores, mais rasas e mais distantes do canal, sendo estes os fatores ambientais que mais distinguem os dois tipos de poça. A composição e abundância de espécies diferiram entre os tipos de poça e ao longo do ano, sendo em arenosas Gerreidae e Gobiidae as principais famílias e em rochosas Gobiidae e Blenniidae. Os fatores ambientais que estruturaram a ictiofauna em cada tipo de poça foram: nas arenosas, a área, profundidade, cobertura algal e distância até o canal; e nas rochosas, temperatura, oxigênio dissolvido e distância do canal. Além do enfoque que vem sendo dado à ictiofauna de poças rochosas, enfatizamos a importância de estudar aquela de poças arenosas por sua elevada riqueza e abundância em espécies, incluindo larvas de diversas famílias. / Tide pools are depressions or cavities of the intertidal substrate formed in both rocky shores and tidal flats during low tide. Studies on fish populations conducted at sandy pools in tidal flats and their comparison with rock pools do not exist. This study is the first one dealing with such questions, emphasizing the relevance of sandy pools for the ecology and conservation of coastal areas. The objectives of this study were (I) to carry out a survey of fish species in sandy and rocky tide pools in a subtropical bay, the Aracá Bay (São Paulo/Brazil); (II) to compare the composition and abundance of fish fauna between sandy and rocky pools; and (III) to investigate which and how environmental factors are related to the composition and distribution of fish fauna of these pools. The structure of fish populations (composition and abundance of species) and environmental factors (area, depth, salinity, temperature, dissolved oxygen, algal coverage percentage and distance from the pools to the channel) were carried out in four campaigns during 2014. In sandy pools, the fish fauna was sampled using hand nets, eugenol and beach seine, following a sampling protocol specially developed for that purpose; in rocky pools, we used eugenol and hand nets. The sandy pools were larger, shallower and farther from the channel, than the rocky ones. The composition and abundance of fish species differed between the types of pools and throughout the year: Gerreidae and Gobiidae were the main families in the sandy pools and Gobiidae and Blenniidae in the rocky ones. The environmental factors that structured the fish fauna in each type of pool were: in sandy area, depth, algal coverage and distance to the channel; in rocky pools, temperature, dissolved oxygen and channel distance. In contrast to the focus that has been given for rocky pools, we emphasize the importance of sandy pools studies because its great richness and abundance of species, including larvae of many families.

Mechanical instabilities such as wrinkling and buckling-driven delamination in thin film-substrate systems have historically been considered as one of structural failure mechanisms, which should be avoided. The past decade has witnesssed rapid growth in harnessing such surface instabilities for a wide range of tunable surface related properties and functionalities, especially in soft materials on small scales. Compared to extensively studied wrinkling on soft substrates and localized buckling driven delamination on stiff substrates, the fundamental mechanics underpinning ordered buckle-delamination on soft substrate over large area and its guidance for potential implications in engineering innovation remain largely to be explored. This thesis aims to partially bridging such a knowledge gap. In this thesis, I exploit how to generate the controllable and globally periodic delaminated buckling patterns in thin films on highly prestrained elastomeric substrates, and then explore the fundamental mechanics of this spontaneous extreme buckling driven periodic delamination, as well as its implications in design of extremely stretchable electronics and interfacial mechanical properties measurement. Compared to wrinkling, one of the benefits of extremely buckling driven delamination is the extraordinarily high aspect ratio of buckles. The large surface roughness and high local curvature could potentially enable extreme surface topographies related properties, such as adhesion, wetting, friction, and optics, as well as augment the extreme stretchability in stretchable optical and electronic devices. In the aim of harnessing this extreme buckling driven delamination, I first explore the formation and evolution of extraordinarily high-aspect-ratio delaminated buckles of thin films on 400% pre-strained elastomers, as well as uncovered the underlying deformation mechanism through combining quantitative theoretical analysis and experimental and numerical approaches. A theoretical framework is developed to describe the formation and evolution process of periodic delaminated buckles, which includes three deformation stages, i.e. onset of localized blisters (Stage I), growth and propagation of delamination (Stage II), and post-buckling after delamination arrest (Stage III). I show that under extreme large compressive strain, the profile of periodic blisters changes from sinusoidal shape to jig-saw-like shape with relative high aspect ratio, which have potential applications for design of extremely stretchable electronics. Equipped with the fundamental mechanics of buckle-delamination in thin films, I then exploit harnessing the spontaneous buckling driven periodic delamination to achieve high stretchability in both metal and silicon films. Experimentally I observe periodic buckle-delaminated patterns over large area, accompanied by highly ordered transversely cracking patterns, which can be theoretically predicted by simple crack fragments model. I hypothesize that when the width of ribbons is set to be equal or smaller than the theoretically predicted crack fragment width, there would be no cracking fragmentation. This criteria for designing crack-free micro-ribbons is further validated by related experiments. Guided by the validated criteria, I successfully design crack-free and spontaneous delaminated ribbons on highly prestrained elastomer substrates, which provides a high stretchability of about 120% and 400% in Si and Au ribbons, respectively. I further extend the buckling instability-based metrology to systematically measure the mechanical properties of 2D organic conjugated polymer nano-films, which have tremendous promising applications in organic integrated circuits, solar cells, and stretchable devices. I develop a new fabrication strategy to generate buckle-delaminated free-standing organic conjugated polymeric (P3BT/C60) nanosheets. Through both experiments and theoretical analysis, I show that the free-standing buckle-delaminated organic P3BT/C60 nanosheets have significant advantages over the traditional spin-coated wrinkled nanosheets, including the enhanced mechanical properties, a higher level of stretchability with lower electrical resistance, and a wider range of controllable wettability modulation. / Mechanical Engineering

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