Many citizens experience ambivalence – having simultaneously positive and negative evaluations – about changing their behaviour towards a more environmentally friendly lifestyle. Based on 36 studies, this study identifies and synthesises the current evidence on how ambivalence impacts environmental behaviours. In most studies, ambivalence is shown to be directly and negatively associated with environmental behaviours, i.e., higher levels of ambivalence are linked to lower levels of environmentally friendly and unfriendly behaviours. This applies to both types of ambivalence: objective (OA) and subjective (SA). Mediator analyses show, in line with the theory, that SA, not OA, drives behavioural change. In addition, results indicate that ambivalence moderates the relationship between independent–dependent variables mainly negatively, for example, by weakening attitude–behaviour relationships. This review shows the potential of ambivalence to facilitate behaviour change: SA about environmentally friendly behaviour can hinder, whereas SA about environmentally unfriendly behaviour can motivate, behaviour change. In addition, this review highlights some significant knowledge gaps in this body of research. A lack of validated standardised measurements of ambivalence makes it challenging to compare studies and reach conclusions about underlying theoretical constructs. Methods, research designs, and theoretical underpinnings need improvement to fully understand ambivalence and progress towards the transition of environmentally friendly behaviours.
MULTIFILE
This study explores the shape-morphing behavior of 4D-printed structures made from Polylactic Acid (PLA), a prominent bio-sourced shape-memory polymer. Focusing on the response of these structures to thermal stimuli, this research investigates how various printing parameters influence their morphing capabilities. The experimental approach integrates design and slicing, printing using fused deposition modeling (FDM), and a post-printing activation phase in a controlled laboratory environment. This process aims to replicate the external stimuli that induce shape morphing, highlighting the dynamic potential of 4D printing. Utilizing Taguchi’s Design of Experiments (DoE), this study examines the effects of printing speed, layer height, layer width, nozzle temperature, bed temperature, and activation temperature on the morphing behavior. The analysis includes precise measurements of deformation parameters, providing a comprehensive understanding of the morphing process. Regression models demonstrate strong correlations with observed data, suggesting their effectiveness in predicting responses based on control parameters. Additionally, finite element analysis (FEA) modeling successfully predicts the performance of these structures, validating its application as a design tool in 4D printing. This research contributes to the understanding of 4D printing dynamics and offers insights for optimizing printing processes to harness the full potential of shape-morphing materials. It sets a foundation for future research, particularly in exploring the relationship between printing parameters and the functional capabilities of 4D-printed structures.