Page 8 - PERIODIC 2017
P. 8

N          ew Research









              Lorna Softley and Christian van Engers report on   Carbon is the most common anode material used in energy
              some of the exciting and innovative research from   storage devices. The graphene SFB thus allows for the
              the Department of Chemistry                       study of processes occurring in every day materials, such as
              Perkin Group                                      mobile phone batteries.
              The graphene Surface Force Balance - measurement
              of graphene surface energy and application as model   Read more:
              2D carbon pore.                                   Direct measurement of the surface energy of graphene,
                                                                van Engers et al., Nano Letters 2017, DOI: 10.1021/acs.
                                                                nanolett.7b01181
                                                                http://perkin.chem.ox.ac.uk/graphene-surface-
                                                                interactions.aspx


                                                                Bayley Group
                                                                A New Synthetic Retina





              Graphene, an atomic layer of sp  hybridized carbon, has
                                       2
              received significant interest from the scientific community
              due to its potential to impact a wide range of technologies.
              While graphene is slowly entering the market, its surface
              energy has received little attention.
              Access to accurate surface energy values of graphene is
              thus not only of fundamental interest, but provides a useful
              reference for anyone involved in research on graphene
              properties, (surface) modifications, and the implementation   Researchers in the Bayley group* have developed the
              of graphene in devices.                           first artificial retina made of soft materials, which could
                                                                transform the way degenerative eye conditions are treated.
              By implementing graphene in a Surface Force Balance   The biological materials from which the artificial retina is
              (SFB), Christian van Engers – a DPhil in Susan Perkin’s   constructed are more compatible with the body compared
              group, was able to directly measure the surface energy of   with existing, hard material technologies.
              graphene.
                                                                The current device consists of a 4x4 array of bio-pixels
              However, the graphene SFB allows for more than just the   –aqueous droplets in lipid-containing oil, interfaced with
              study of graphene properties. It serves as 2-dimensional   a hydrogel scaffold, to form 16 individual bilayers. The
              carbon pore and is thus ideally suited for the measurement   presence of a light activated protein (bacteriorhodopsin)
              of forces across electrolytes between graphene electrodes.
                                                                in the lipid bilayers drives a flow of ions across the bilayers
                                                                when illuminated by green light. This flow of ions produces
                                                                electrical signals that mimic the function of the natural
                                                                retina.
                                                                Photomasks were used to selectively illuminate individual
                                                                bio-pixels to show that each one could produce an
                                                                electrical signal independently of the others. This
                                                                ‘controllable patterned current generation’ behaviour
                                                                has not previously been achieved with soft materials and
                                                                could allow for targeted stimulation of specific neurons.





          8
              Periodic       The Magazine of the Department of Chemistry
   3   4   5   6   7   8   9   10   11   12   13