Cotton-based nanocrystalline cellulose (NCC), also known as nanopaper, one of the major sources of renewable materials, is a promising substrate and component for producing low cost fully recyclable flexible paper electronic devices and systems due to its properties (lightweight, stiffness, non-toxicity, transparency, low thermal expansion, gas impermeability and improved mechanical properties).Here, we have demonstrated for the first time a thin transparent nanopaper-based field effect transistor (FET) where NCC is simultaneously used as the substrate and as the gate dielectric layer in an 'interstrate' structure, since the device is built on both sides of the NCC films; while the active channel layer is based on oxide amorphous semiconductors, the gate electrode is based on a transparent conductive oxide.Such hybrid FETs present excellent operating characteristics such as high channel saturation mobility (>7 cm(2) V (-1) s(-1)), drain-source current on/off modulation ratio higher than 10(5), enhancement n-type operation and subthreshold gate voltage swing of 2.11 V/decade. The NCC film FET characteristics have been measured in air ambient conditions and present good stability, after two weeks of being processed, without any type of encapsulation or passivation layer. The results obtained are comparable to ones produced for conventional cellulose paper, marking this out as a promising approach for attaining high-performance disposable electronics such as paper displays, smart labels, smart packaging, RFID (radio-frequency identification) and point-of-care systems for self-analysis in bioscience applications, among others.

One strategy that has gained much attention in the last decades is the understanding and further mimicking of structures and behaviours found in nature, as inspiration to develop materials with additional functionalities. This review presents recent advances in stimuli-responsive gels with emphasis on functional hydrogels and microgels. The first part of the review highlights the high impact of stimuli-responsive hydrogels in materials science. From macro to micro scale, the review also collects the most recent studies on the preparation of hybrid polymeric microgels composed of a nanoparticle (able to respond to external stimuli), encapsulated or grown into a stimuli-responsive matrix (microgel). This combination gave rise to interesting multi-responsive functional microgels and paved a new path for the preparation of multi-stimuli “smart” systems. Finally, special attention is focused on a new generation of functional stimuli-responsive polymer hydrogels able to self-shape (shape-memory) and/or self-repair. This last functionality could be considered as the closing loop for smart polymeric gels.

The integration of bioinspired chiral cellulose nanocrystal (CNC) films into transistor devices with distinct sensing properties for left‐ and right‐handed circular polarized light (LCPL and RCPL, respectively) is reported. The CNC films with a left‐handed internal long‐range order are infiltrated with sodium ions to yield solid‐state electrolytes with photonic properties capable of LCPL reflection and RCPL transmission. They are employed as gate dielectrics in sputtered amorphous indium–gallium–zinc oxide (a‐IGZO) transistors. The obtained devices operate in depletion mode at low voltages (<2 V) with On–Off ratios of up to 7 orders of magnitude, subthreshold swings around 80 mV dec⁻¹, and saturation mobilities up to 9 cm² V⁻¹ s⁻¹. Combining the photonic character of the CNC films with the light sensitivity of a‐IGZO, the devices are capable of discrimination between LCPL and RCPL signals in the blue region. These type of devices can find application in photonics, emission, conversion, or sensing with CPL but also imaging or spintronics.