E-­‐textile development methods

Woven  textiles  consist  of  the  orthogonal  interlacing  of  warp  (vertical  threads)  and  weft   (intercepting  horizontal  threads)  yarns,  usually  forming  a  tight  stable  cloth  if  woven  at  a   dense   sett.   Woven   e-­‐textiles   are   of   specific   focus   in   this   research   project,   as   the   reviewed   literature   in   the   field   revealed   a   lack   of   in-­‐depth   structural   investigation   of   integrated  woven  e-­‐textiles  (discussed  further  with  examples  in  chapter  2).    

The  reviewed  literature  presented  two  main  development  approaches  in  existing  woven   e-­‐textiles.   These   were   classified   by   the   researcher   as   ͚ĐƌĞĂƚŝǀĞ   craft   mĞƚŚŽĚƐ͛   and   ͚ƚĞĐŚŶŝĐĂů  materials  approach͛͘  This  section  will  define  the  two  approaches.  (Specific  e-­‐ textile  examples  related  to  these  approaches  will  be  discussed  in  chapter  2.)    

x Creative   craft   methods   ʹ   this   approach   uses   creative   investigations   of   textile   design   and   craft   making   processes,   to   develop   e-­‐textiles   with   electronic   functional   capability.   In   this   approach   there   is   conscious   consideration   of   the   textile  construction  form  (i.e.  aesthetic  and  textile  structures).  The  outputs  via   this   approach   are   mainly   unique   one-­‐off   pieces   or   small   collections   of   statement   designs,   to   exhibit   or   for   particular   applications   by   predominantly   designers,   researchers,   artists   or   hobbyists.   Specifically   woven   e-­‐textiles   developed   via   creative   craft   methods   apply   some   consideration   to   integrate   electronic  function  into  the  woven  construction,  i.e.  utilising  some  of  the  woven   architecture  to  integrate  conductive  yarns  and/  or  components.  However,  this   approach   does   not   fully   exploit   these   structures   for   electronic   functionality   beyond  basic  structures,  due  to  limited  woven  expertise.    

x Technical  materials  approach  ʹ  this  approach  develops  e-­‐textile  materials  with   a   dominant   focus   on   function.   Empirical   investigations   are   applied   to   investigate   technological   functions,   electronic   components,   and/   or   testing   technical   concepts   for   e-­‐textiles.   The   dominant   emphasis   is   on   a   technical   objective   where  technical  technology/  engineering   expertise   is   involved   in   the   development   of   the   e-­‐textile.   The   outputs   of   this   approach   are   for   scientific,   engineering   and   technical   domains   and   are   extended   for   industrial   manufacture.   Specifically,   woven   e-­‐textiles   developed   via   technical   material   approaches   are   functionally   driven,   where   structures   are   predominantly   selected   to   achieve   the   required   electrical   function.   Thus,   the   woven   architecture   is   not   usually   utilised   in   terms   of   form,   and   compromises   the   aesthetics  of  the  material  due  to  insufficient  woven  knowledge.  

Neither   of   the   two   approaches   has   fully   exploited   woven   structures   for   form   and   function   that   woven   e-­‐textiles   are   able   to   realise.   Although   creative   craft   approaches   use   some   woven   structural   integration,   this   is   not   manipulated   to   push   the   limits   of   weaving   and   its   potential   for   e-­‐textiles.   Each   of   the   described   approaches   have   predominantly   focused   on   form   (creative   craft   methods),   or   function   (technical   materials   approach),   where   this   compromises   other   parts   of   the   e-­‐textile   design.   Although   there   are   slight   nuances   in   both   approaches   of   some   reviewed   projects,   i.e.   where   there   is   an   overlap   of   approaches   (further   discussed   in   chapter   2),   the   projects   mainly  use  one  of  the  single  approaches.  Thus,  this  PhD  research  sought  to  investigate   both  creative  craft  and  technical  material  approaches  to  avoid  compromising  aspects  of   form  or  function  of  woven  e-­‐textile  designs.  

An   example   of   a   technical   materials   approach   project   is   by   ETH   Zurich,   where   a   strip   sensor   was   developed   for   integration   into   a   woven   textile   (Cherenack   et   al.,   2010;   Kinkeldei   et   al.,   2009)   (Figure   1.2).   The   researchers   who   developed   this   project   were   from   electronic   engineering,   materials   science   and   IT   backgrounds.   The   project   was   developed   through   a   focused   technical   materials   approach,   where   the   textile   construction   was   not   fully   utilised   to   support   the   e-­‐textile.   Instead   the   woven   construction,  a  single  cloth  twill  configuration  (specific  twill  type  not  documented),  was   used  as  a  frame  to  hold  the  electronics  where  the  component  was  loosely  interwoven   into  the  warp.  The  warp  used  only  two  conductive  yarn  tracks  that  interconnected  with  

the   component.   The   woven   construction   was   not   investigated   as   part   of   the   design/objective,  where  it  could  have  potentially  helped  to  enhance  the  final  design.  For   example,   more   conductive   warp   and   weft   tracks   integration   would   have   increased   connectivity   to   the   component.   Also,   a   tighter   weave   structure   would   have   provided   securer   connection   between   the   weave   and   the   component,   potentially   negating   the   use  of  glue  (this  example  is  further  discussed  in  chapters  2  and  8).  Although  this  project   successfully   achieved   the   intended   temperature   sensor   function,   the   research   did   not   extend  the  capabilities  of  woven  structures.    

Figure  1.2  d,͛Ɛ  woven  e-­‐fibre  temperature  sensor  (Cherenack  et  al.,  2010)  

^ƵďdĞůĂ͛Ɛ  Black  Wall  Hanging  piece  is  an  example  of  creative  craft  methods  applied  to  a   woven  e-­‐textile  (Figure  1.3,  also  discussed  further  in  chapters  2  and  8).  Barbara  Layne  is   Director   at   Studio   SubTela,   where   she   works   with   graduates   in   visual   arts   and   engineering.   Layne   is   a   textile   artist   who   has   weaving   knowledge.   The   Black   Wall   Hanging  piece  adapted  weaving  processes  to  integrate  electronic  function  (Layne,  Studio   Sub   Tela   and   The   Hexagram   Institute,   2006).   The   wall   hanging   utilises   the   woven   structure  to  position  and  place  each  LED  in  specific  spaces  during  the  weaving  process   on  the  loom.  A  basic  2/2  twill  woven  structure  was  applied  in  a  single  cloth.  The  space   between  each  2/2  twill  structure  (i.e.  two  threads  lifted  up,  while  the  next  two  threads   are  left  down),  are  used  to  interweave  weft  yarn  and  the  LED  components;  the  visible   spaces  between  the  twill  structures  shows  the  LEDs/  weft  yarns.  The  weave  structures   were   designed   for   the   positioning   of   the   LEDs,   however,   they   could   have   further   contributed  to  the  electronic  function  by  integrating  conductive  yarns  in  both  the  warp   and  weft,  to  support  and  increase  the  circuit  interconnections.  Conductive  yarns  would   have  been  more  suitable  than  hard  wires  because  they  are  more  durable  under  weaving   tension  due  to  their  slight  fibrous  stretch  quality.  

Figure  1.3  LED  strands  being  woven  on  the  loom  (Layne,  Studio  Sub  Tela  and  The  Hexagram  Institute,   2006)  

There   is   an   opportunity   to   address   both   form   and   function   of   woven   e-­‐textiles,   by   simultaneously  considering  both  of  these  areas.  This  can  be  progressed  by  establishing   closer   nuances   between   technical   material   approaches   and   creative   craft   methods,   drawing  on  in-­‐depth  woven  textile  expertise.  This  would  enable  woven  structures  to  be   adapted  and  fully  utilised  to  enhance  form  and  function  of  e-­‐textiles.