In this study, silica nanoparticle was synthesised and used to promote lysozyme crystallisation effectively against high concentrations of protein impurity (bovine serum albumin (BSA); concentration = 25.0 -50.0 mg/mL vs 5.0 -25.0 mg/mL for lysozyme) at 1 mL scale, demonstrating that crystallisation is a viable and scalable protein purification technology with the aid of heterogeneous nucleants. The silica nanoparticle expedited the crystallisation of lysozyme through the enhancement of nucleation, significantly improving the process productivity. Furthermore, this study demonstrates the proper use of nanoparticle in terms of cycle time, as the improvement of productivity by silica nanoparticle has a monomodal peak shape over time.

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Composite of reduced graphene oxide (rGO) and polyaniline (PANI) have gained much attention in industrial applications especially for the fabrication of supercapacitor and flexible sensors. Nevertheless, existing studies mainly focus on the application efficiency and are lacking information on how morphology of the nanoparticles can affect the electrode properties.Herein, the effects of shape of PANI on the electrode resistivity were systematically investigated. PANI of different shapes was synthesized using different reagents, namely H 2 SO 4 , CH 3 COOH, H 2 O, and NH 3 ÁH 2 O, which induced formation of globule, tube, plate, and flake-like PANI. rGO-PANI composite was then produced using ex situ method and cast on a PVC substrate to form a flexible electrode. The rGO-PANI globules displayed superior electrical conductivity owing to its high protonation level. The resistivity of this sample was found to be 0.015 ± 0.002 Ωcm, which is lowest as compared to the counterparts. Interestingly, electrode made of rGO-PANI plates had a slightly lower electrical resistivity than rGO-PANI tubes despite its low protonation level. It is speculate that the aspect ratio characteristic of the PANI might have influence the electron mobility. rGO-PANI electrode was found to exhibit a lower specific resistivity than pure rGO and pure PANI, evincing the presence of synergism.

Polyaniline (PANI) is a conductive polymer that is attracting much attention nowadays especially for the design of flexible supercapacitors and sensors. One of the commonly used methods to synthesize PANI is chemical oxidative polymerization (COP). In the present work, the effects of (i) polymerization time and (ii) type of dopant media used in COP were evaluated and correlated to the morphological and electrical properties of the formed PANI. In terms of morphological properties, it was found that extending the polymerization time of COP in hydrochloric acid (HCl) medium from 1 to 5 h induced the formation of regular flake‐ and globule‐like structures. Despite that, there was not much change in the surface functional groups, as verified from the infrared absorption spectrum. An intermingled structure containing (i) stacking of flake‐like particles and (ii) interconnection of long fibrous‐like particles with fewer branches was seen for PANI produced at 3 h of polymerization time. Such a unique morphological property is suggested to lower the electrical resistance of PANI to 0.56 × 103 Ω. On the other hand, by changing the dopant medium from HCl to sulfuric acid (H2SO4), acetic acid (CH3COOH), water (H2O) and ammonium hydroxide (NH3⋅H2O), the PANI morphology was altered to globular shape with cauliflower‐like structure, tube‐like structure, plate‐like structure and flake‐like structure, respectively. The resistance of these PANIs was successfully tuned and found to increase following the order of PANI–H2SO4 < PANI–CH3COOH < PANI–H2O < PANI–NH3⋅H2O. © 2023 Society of Industrial Chemistry.