Enzyme responsive materials (ERMs) are a class of stimuli responsive materials with broad application potential in biological settings. This review highlights current and potential future design strategies for ERMs and provides an overview of the present state of the art in the area.

Self-sorting in low molecular weight hydrogels can be used to prepare gels with different types of mechanical properties.

The photoconductivity of perylene-bisimide gelators correlates with the perylene radical anion, which is unusually highly stable in air for many hours.

A range of functionalised-dipeptides are shown here to form gels on addition of Ca²⁺ to solutions at high pH. We show that the ability to form gels correlates with the hydrophobicity of the dipeptides, which determines whether worm-like micelles are formed at high pH. The dipeptides can be functionalised with a number of different groups including naphthalene rings as well as alkyl chains. The effect of aging on stock solutions and gels is discussed. We show that gels can also be formed when trivalent or polyvalent salts are added.

Amphiphilic reduced graphene oxide (rGO) is an efficient emulsifier for water-in-divinylbenzene (DVB) high internal phase emulsions. The polymerisation of the continuous DVB phase of the emulsion template and removal of water results in macroporous poly(divinylbenzene) (polyDVB). Subsequent pyrolysis of the poly(DVB) macroporous polymers yields ‘all-carbon’ foams containing micropores alongside emulsion templated-macropores, resulting in hierarchical porosity. The synthesis of carbon foams, or ‘carboHIPEs’, from poly(DVB) produced by polymerisation of rGO stabilised HIPEs provides both exceptionally high surface areas (up to 1820 m² g⁻¹) and excellent electrical conductivities (up to 285 S m⁻¹), competing with the highest figures reported for carboHIPEs. The use of a 2D carbon emulsifier results in the elimination of post-carbonisation treatments to remove standard inorganic particulate emulsifiers, such as silica particles. It is demonstrated that rGO containing carboHIPEs are good candidates for supercapacitor electrodes where carboHIPEs derived from more conventional polymerised silica-stabilised HIPEs perform poorly. Supercapacitor devices featured a room-temperature ionic liquid electrolyte and electrodes derived from either rGO- or silica-containing poly(DVB)HIPEs demonstrated a maximum specific capacitance of 26 F g⁻¹, an energy density of 5.2 W h kg⁻¹ and a power density of 280 W kg⁻¹.